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<!-- RRD ActiveDisclosure(SM) XBRL Linkbase Document - http://www.financial.rrd.com/ -->
<!-- Creation Date      : 2016-02-29T19:48:44.9896692+00:00 -->
<!-- Version            : 2.1.0.1 -->
<!-- Package ID         : 0BFE3679E78F2359CB450E8C8B3B2AD0-0000906709-001512 -->
<!-- Copyright (c) 2016 R. R. Donnelley &amp; Sons Company. All Rights Reserved. -->
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherAccruedLiabilitiesCurrent" xlink:type="locator" xlink:label="us-gaap_OtherAccruedLiabilitiesCurrent" />
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherAccruedLiabilitiesCurrent" xlink:to="us-gaap_OtherAccruedLiabilitiesCurrent_lbl" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_InterestPayableCurrent" xlink:type="locator" xlink:label="us-gaap_InterestPayableCurrent" />
    <label xml:lang="en-US" xlink:label="us-gaap_InterestPayableCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest payable</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_LiabilitiesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities Current</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SeniorLongTermNotes" xlink:type="locator" xlink:label="us-gaap_SeniorLongTermNotes" />
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SeniorLongTermNotes" xlink:to="us-gaap_SeniorLongTermNotes_lbl" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CapitalLeaseObligationsNoncurrent" xlink:type="locator" xlink:label="us-gaap_CapitalLeaseObligationsNoncurrent" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StockholdersEquity" xlink:type="locator" xlink:label="us-gaap_StockholdersEquity" />
    <label xml:lang="en-US" xlink:label="us-gaap_StockholdersEquity_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total stockholders&#8217; equity</label>
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:type="locator" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity" />
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    <label xml:lang="en-US" xlink:label="nktr_PreferredStockShareDesignated_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Preferred stock, shares designated.</label>
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" xlink:type="locator" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" />
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" xlink:to="us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_lbl" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PreferredStockParOrStatedValuePerShare" xlink:type="locator" xlink:label="us-gaap_PreferredStockParOrStatedValuePerShare" />
    <label xml:lang="en-US" xlink:label="us-gaap_PreferredStockParOrStatedValuePerShare_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Preferred stock, par value</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PreferredStockParOrStatedValuePerShare" xlink:to="us-gaap_PreferredStockParOrStatedValuePerShare_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_PreferredStockParOrStatedValuePerShare_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Preferred Stock Par Or Stated Value Per Share</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PreferredStockSharesAuthorized" xlink:type="locator" xlink:label="us-gaap_PreferredStockSharesAuthorized" />
    <label xml:lang="en-US" xlink:label="us-gaap_PreferredStockSharesAuthorized_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Preferred stock, shares authorized</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PreferredStockSharesAuthorized" xlink:to="us-gaap_PreferredStockSharesAuthorized_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_PreferredStockSharesAuthorized_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Preferred Stock Shares Authorized</label>
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    <label xml:lang="en-US" xlink:label="nktr_PreferredStockShareDesignated_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Preferred Stock Share Designated</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PreferredStockSharesIssued" xlink:type="locator" xlink:label="us-gaap_PreferredStockSharesIssued" />
    <label xml:lang="en-US" xlink:label="us-gaap_PreferredStockSharesIssued_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Preferred stock, shares issued</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PreferredStockSharesIssued" xlink:to="us-gaap_PreferredStockSharesIssued_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_PreferredStockSharesIssued_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Preferred Stock Shares Issued</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PreferredStockSharesOutstanding" xlink:type="locator" xlink:label="us-gaap_PreferredStockSharesOutstanding" />
    <label xml:lang="en-US" xlink:label="us-gaap_PreferredStockSharesOutstanding_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Preferred stock, shares outstanding</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PreferredStockSharesOutstanding" xlink:to="us-gaap_PreferredStockSharesOutstanding_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_PreferredStockSharesOutstanding_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Preferred Stock Shares Outstanding</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:type="locator" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare" />
    <label xml:lang="en-US" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, par value</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockParOrStatedValuePerShare" xlink:to="us-gaap_CommonStockParOrStatedValuePerShare_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock Par Or Stated Value Per Share</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CommonStockSharesAuthorized" xlink:type="locator" xlink:label="us-gaap_CommonStockSharesAuthorized" />
    <label xml:lang="en-US" xlink:label="us-gaap_CommonStockSharesAuthorized_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, shares authorized</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockSharesAuthorized" xlink:to="us-gaap_CommonStockSharesAuthorized_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_CommonStockSharesAuthorized_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock Shares Authorized</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CommonStockSharesIssued" xlink:type="locator" xlink:label="us-gaap_CommonStockSharesIssued" />
    <label xml:lang="en-US" xlink:label="us-gaap_CommonStockSharesIssued_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, shares issued</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockSharesIssued" xlink:to="us-gaap_CommonStockSharesIssued_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_CommonStockSharesIssued_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock Shares Issued</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CommonStockSharesOutstanding" xlink:type="locator" xlink:label="us-gaap_CommonStockSharesOutstanding" />
    <label xml:lang="en-US" xlink:label="us-gaap_CommonStockSharesOutstanding_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, shares outstanding</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockSharesOutstanding" xlink:to="us-gaap_CommonStockSharesOutstanding_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_CommonStockSharesOutstanding_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock Shares Outstanding</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_NonCashRoyaltyRevenueRelatedToSaleOfFutureRoyalties" xlink:type="locator" xlink:label="nktr_NonCashRoyaltyRevenueRelatedToSaleOfFutureRoyalties" />
    <label xml:lang="en-US" xlink:label="nktr_NonCashRoyaltyRevenueRelatedToSaleOfFutureRoyalties_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Non cash royalty revenue related to sale future royalties.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_NonCashRoyaltyRevenueRelatedToSaleOfFutureRoyalties" xlink:to="nktr_NonCashRoyaltyRevenueRelatedToSaleOfFutureRoyalties_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_LicenseCollaborationOtherRevenue" xlink:type="locator" xlink:label="nktr_LicenseCollaborationOtherRevenue" />
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_LicenseCollaborationOtherRevenue" xlink:to="nktr_LicenseCollaborationOtherRevenue_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_NonCashInterestExpenseRelatedToSaleOfRoyalties" xlink:type="locator" xlink:label="nktr_NonCashInterestExpenseRelatedToSaleOfRoyalties" />
    <label xml:lang="en-US" xlink:label="nktr_NonCashInterestExpenseRelatedToSaleOfRoyalties_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Non-cash interest expense related to sale of royalties.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_NonCashInterestExpenseRelatedToSaleOfRoyalties" xlink:to="nktr_NonCashInterestExpenseRelatedToSaleOfRoyalties_lbl" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeStatementAbstract" xlink:type="locator" xlink:label="us-gaap_IncomeStatementAbstract" />
    <label xml:lang="en-US" xlink:label="us-gaap_IncomeStatementAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Income Statement [Abstract]</label>
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SalesRevenueNetAbstract" xlink:type="locator" xlink:label="us-gaap_SalesRevenueNetAbstract" />
    <label xml:lang="en-US" xlink:label="us-gaap_SalesRevenueNetAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Revenue:</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_SalesRevenueNetAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Sales Revenue Net [Abstract]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SalesRevenueGoodsNet" xlink:type="locator" xlink:label="us-gaap_SalesRevenueGoodsNet" />
    <label xml:lang="en-US" xlink:label="us-gaap_SalesRevenueGoodsNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Product sales</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_SalesRevenueGoodsNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Sales Revenue Goods Net</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RoyaltyRevenue" xlink:type="locator" xlink:label="us-gaap_RoyaltyRevenue" />
    <label xml:lang="en-US" xlink:label="us-gaap_RoyaltyRevenue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Royalty revenue</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RoyaltyRevenue" xlink:to="us-gaap_RoyaltyRevenue_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_RoyaltyRevenue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Royalty Revenue</label>
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    <label xml:lang="en-US" xlink:label="nktr_NonCashRoyaltyRevenueRelatedToSaleOfFutureRoyalties_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Non Cash Royalty Revenue Related To Sale Of Future Royalties</label>
    <label xml:lang="en-US" xlink:label="nktr_LicenseCollaborationOtherRevenue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">License, collaboration and other revenue</label>
    <label xml:lang="en-US" xlink:label="nktr_LicenseCollaborationOtherRevenue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">License Collaboration Other Revenue</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_Revenues" xlink:type="locator" xlink:label="us-gaap_Revenues" />
    <label xml:lang="en-US" xlink:label="us-gaap_Revenues_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total revenue</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_Revenues_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Revenues</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CostsAndExpensesAbstract" xlink:type="locator" xlink:label="us-gaap_CostsAndExpensesAbstract" />
    <label xml:lang="en-US" xlink:label="us-gaap_CostsAndExpensesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating costs and expenses:</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CostsAndExpensesAbstract" xlink:to="us-gaap_CostsAndExpensesAbstract_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_CostsAndExpensesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Costs And Expenses [Abstract]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CostOfGoodsSold" xlink:type="locator" xlink:label="us-gaap_CostOfGoodsSold" />
    <label xml:lang="en-US" xlink:label="us-gaap_CostOfGoodsSold_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cost of goods sold</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CostOfGoodsSold" xlink:to="us-gaap_CostOfGoodsSold_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_CostOfGoodsSold_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Cost Of Goods Sold</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:type="locator" xlink:label="us-gaap_ResearchAndDevelopmentExpense" />
    <label xml:lang="en-US" xlink:label="us-gaap_ResearchAndDevelopmentExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Research and development</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ResearchAndDevelopmentExpense" xlink:to="us-gaap_ResearchAndDevelopmentExpense_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_ResearchAndDevelopmentExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Research And Development Expense</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:type="locator" xlink:label="us-gaap_GeneralAndAdministrativeExpense" />
    <label xml:lang="en-US" xlink:label="us-gaap_GeneralAndAdministrativeExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">General and administrative</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GeneralAndAdministrativeExpense" xlink:to="us-gaap_GeneralAndAdministrativeExpense_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_GeneralAndAdministrativeExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">General And Administrative Expense</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CostsAndExpenses" xlink:type="locator" xlink:label="us-gaap_CostsAndExpenses" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetIncomeLoss" xlink:type="locator" xlink:label="us-gaap_NetIncomeLoss" />
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    <label xml:lang="en-US" xlink:label="us-gaap_NetIncomeLoss_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Net Income Loss</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EarningsPerShareBasicAndDiluted" xlink:type="locator" xlink:label="us-gaap_EarningsPerShareBasicAndDiluted" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract" xlink:type="locator" xlink:label="us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AvailableForSaleSecuritiesChangeInNetUnrealizedHoldingGainLoss" xlink:type="locator" xlink:label="us-gaap_AvailableForSaleSecuritiesChangeInNetUnrealizedHoldingGainLoss" />
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    <label xml:lang="en-US" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accumulated Other Comprehensive Income/(Loss) [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeMember_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Accumulated Other Comprehensive Income [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:type="locator" xlink:label="us-gaap_RetainedEarningsMember" />
    <label xml:lang="en-US" xlink:label="us-gaap_RetainedEarningsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accumulated Deficit [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RetainedEarningsMember" xlink:to="us-gaap_RetainedEarningsMember_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_RetainedEarningsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Retained Earnings [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StatementLineItems" xlink:type="locator" xlink:label="us-gaap_StatementLineItems" />
    <label xml:lang="en-US" xlink:label="us-gaap_StatementLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Statement [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementLineItems_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_StatementLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Statement [Line Items]</label>
    <label xml:lang="en-US" xlink:label="us-gaap_StockholdersEquity_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Beginning Balance</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SharesOutstanding" xlink:type="locator" xlink:label="us-gaap_SharesOutstanding" />
    <label xml:lang="en-US" xlink:label="us-gaap_SharesOutstanding_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Beginning Balance, Shares</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharesOutstanding" xlink:to="us-gaap_SharesOutstanding_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_SharesOutstanding_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Shares Outstanding</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodValueNewIssues" />
    <label xml:lang="en-US" xlink:label="us-gaap_StockIssuedDuringPeriodValueNewIssues_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Sale of common stock, net of issuance costs of $617</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:to="us-gaap_StockIssuedDuringPeriodValueNewIssues_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_StockIssuedDuringPeriodValueNewIssues_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Stock Issued During Period Value New Issues</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodSharesNewIssues" />
    <label xml:lang="en-US" xlink:label="us-gaap_StockIssuedDuringPeriodSharesNewIssues_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Sale of common stock, Shares</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:to="us-gaap_StockIssuedDuringPeriodSharesNewIssues_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_StockIssuedDuringPeriodSharesNewIssues_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Stock Issued During Period Shares New Issues</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation" xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation" />
    <label xml:lang="en-US" xlink:label="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Shares issued under equity compensation plans</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation" xlink:to="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Stock Issued During Period Value Share Based Compensation</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" />
    <label xml:lang="en-US" xlink:label="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Shares issued under equity compensation plans, Shares</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:to="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Stock Issued During Period Shares Share Based Compensation</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:type="locator" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" />
    <label xml:lang="en-US" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock-based compensation</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:to="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value</label>
    <label xml:lang="en-US" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTax_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other comprehensive loss</label>
    <label xml:lang="en-US" xlink:label="us-gaap_StockholdersEquity_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Ending Balance</label>
    <label xml:lang="en-US" xlink:label="us-gaap_SharesOutstanding_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Ending Balance, Shares</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts" xlink:type="locator" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts" />
    <label xml:lang="en-US" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock issuance costs</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts" xlink:to="us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Adjustments To Additional Paid In Capital Stock Issued Issuance Costs</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_LossFromRedemptionPremiumAndIncrementalInterestOnSecuredDebt" xlink:type="locator" xlink:label="nktr_LossFromRedemptionPremiumAndIncrementalInterestOnSecuredDebt" />
    <label xml:lang="en-US" xlink:label="nktr_LossFromRedemptionPremiumAndIncrementalInterestOnSecuredDebt_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Loss from redemption premium and incremental interest on secured debt.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_LossFromRedemptionPremiumAndIncrementalInterestOnSecuredDebt" xlink:to="nktr_LossFromRedemptionPremiumAndIncrementalInterestOnSecuredDebt_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_IncreaseDecreaseInAccruedClinicalTrialExpenses" xlink:type="locator" xlink:label="nktr_IncreaseDecreaseInAccruedClinicalTrialExpenses" />
    <label xml:lang="en-US" xlink:label="nktr_IncreaseDecreaseInAccruedClinicalTrialExpenses_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Accrued clinical trial expenses.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_IncreaseDecreaseInAccruedClinicalTrialExpenses" xlink:to="nktr_IncreaseDecreaseInAccruedClinicalTrialExpenses_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_IncreaseDecreaseInMilestonePaymentLiabilities" xlink:type="locator" xlink:label="nktr_IncreaseDecreaseInMilestonePaymentLiabilities" />
    <label xml:lang="en-US" xlink:label="nktr_IncreaseDecreaseInMilestonePaymentLiabilities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Increase(Decrease) in Milestone Payment Liabilities</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_IncreaseDecreaseInMilestonePaymentLiabilities" xlink:to="nktr_IncreaseDecreaseInMilestonePaymentLiabilities_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_RepaymentOfAndProceedsFromSaleOfFutureRoyaltiesNetOfTransactionCosts" xlink:type="locator" xlink:label="nktr_RepaymentOfAndProceedsFromSaleOfFutureRoyaltiesNetOfTransactionCosts" />
    <label xml:lang="en-US" xlink:label="nktr_RepaymentOfAndProceedsFromSaleOfFutureRoyaltiesNetOfTransactionCosts_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Repayment Of And Proceeds From Sale Of Future Royalties Net Of Transaction Costs</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_RepaymentOfAndProceedsFromSaleOfFutureRoyaltiesNetOfTransactionCosts" xlink:to="nktr_RepaymentOfAndProceedsFromSaleOfFutureRoyaltiesNetOfTransactionCosts_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_ProceedsFromIssuanceOfCommonStockNetOfIssuanceCosts" xlink:type="locator" xlink:label="nktr_ProceedsFromIssuanceOfCommonStockNetOfIssuanceCosts" />
    <label xml:lang="en-US" xlink:label="nktr_ProceedsFromIssuanceOfCommonStockNetOfIssuanceCosts_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Proceeds From Issuance Of Common Stock Net Of Issuance Costs</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_ProceedsFromIssuanceOfCommonStockNetOfIssuanceCosts" xlink:to="nktr_ProceedsFromIssuanceOfCommonStockNetOfIssuanceCosts_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_PropertyAndEquipmentAcquiredThroughCapitalLeasesAndOtherFinancing" xlink:type="locator" xlink:label="nktr_PropertyAndEquipmentAcquiredThroughCapitalLeasesAndOtherFinancing" />
    <label xml:lang="en-US" xlink:label="nktr_PropertyAndEquipmentAcquiredThroughCapitalLeasesAndOtherFinancing_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Property And Equipment Acquired Through Capital Leases And Other Financing</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_PropertyAndEquipmentAcquiredThroughCapitalLeasesAndOtherFinancing" xlink:to="nktr_PropertyAndEquipmentAcquiredThroughCapitalLeasesAndOtherFinancing_lbl" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StatementOfCashFlowsAbstract" xlink:type="locator" xlink:label="us-gaap_StatementOfCashFlowsAbstract" />
    <label xml:lang="en-US" xlink:label="us-gaap_StatementOfCashFlowsAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Statement Of Cash Flows [Abstract]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementOfCashFlowsAbstract" xlink:to="us-gaap_StatementOfCashFlowsAbstract_lbl" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" />
    <label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash flows from operating activities:</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Net Cash Provided By Used In Operating Activities [Abstract]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:type="locator" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" />
    <label xml:lang="en-US" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Adjustments to reconcile net loss to net cash used in operating activities:</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Adjustments To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities [Abstract]</label>
    <label xml:lang="en-US" xlink:label="nktr_NonCashRoyaltyRevenueRelatedToSaleOfFutureRoyalties_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel">Non-cash royalty revenue related to sale of future royalties</label>
    <label xml:lang="en-US" xlink:label="nktr_NonCashInterestExpenseRelatedToSaleOfRoyalties_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Non-cash interest expense on liability related to sale of future royalties</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:type="locator" xlink:label="us-gaap_AllocatedShareBasedCompensationExpense" />
    <label xml:lang="en-US" xlink:label="us-gaap_AllocatedShareBasedCompensationExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock-based compensation</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AllocatedShareBasedCompensationExpense" xlink:to="us-gaap_AllocatedShareBasedCompensationExpense_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_AllocatedShareBasedCompensationExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Allocated Share Based Compensation Expense</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DepreciationAndAmortization" xlink:type="locator" xlink:label="us-gaap_DepreciationAndAmortization" />
    <label xml:lang="en-US" xlink:label="us-gaap_DepreciationAndAmortization_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Depreciation and amortization</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DepreciationAndAmortization" xlink:to="us-gaap_DepreciationAndAmortization_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_DepreciationAndAmortization_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Depreciation And Amortization</label>
    <label xml:lang="en-US" xlink:label="nktr_LossFromRedemptionPremiumAndIncrementalInterestOnSecuredDebt_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loss from redemption premium and incremental interest on 12% senior secured notes</label>
    <label xml:lang="en-US" xlink:label="nktr_LossFromRedemptionPremiumAndIncrementalInterestOnSecuredDebt_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Loss From Redemption Premium And Incremental Interest On Secured Debt</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_WriteOffOfDeferredDebtIssuanceCost" xlink:type="locator" xlink:label="us-gaap_WriteOffOfDeferredDebtIssuanceCost" />
    <label xml:lang="en-US" xlink:label="us-gaap_WriteOffOfDeferredDebtIssuanceCost_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Write-off of deferred financing costs on 12% senior secured notes</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_WriteOffOfDeferredDebtIssuanceCost" xlink:to="us-gaap_WriteOffOfDeferredDebtIssuanceCost_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_WriteOffOfDeferredDebtIssuanceCost_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Write Off Of Deferred Debt Issuance Cost</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherNoncashIncomeExpense" xlink:type="locator" xlink:label="us-gaap_OtherNoncashIncomeExpense" />
    <label xml:lang="en-US" xlink:label="us-gaap_OtherNoncashIncomeExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Other non-cash transactions</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherNoncashIncomeExpense" xlink:to="us-gaap_OtherNoncashIncomeExpense_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_OtherNoncashIncomeExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Other Noncash Income Expense</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" />
    <label xml:lang="en-US" xlink:label="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Changes in assets and liabilities:</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:to="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Increase Decrease In Operating Capital [Abstract]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInAccountsReceivable" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInInventories" xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInInventories" />
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    <label xml:lang="en-US" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingAssets_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Other assets</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingAssets_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Increase Decrease In Other Operating Assets</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayable" xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInAccountsPayable" />
    <label xml:lang="en-US" xlink:label="us-gaap_IncreaseDecreaseInAccountsPayable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accounts payable</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_IncreaseDecreaseInAccountsPayable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Increase Decrease In Accounts Payable</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities" xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities" />
    <label xml:lang="en-US" xlink:label="us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accrued compensation</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities" xlink:to="us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Increase Decrease In Employee Related Liabilities</label>
    <label xml:lang="en-US" xlink:label="nktr_IncreaseDecreaseInAccruedClinicalTrialExpenses_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accrued clinical trial expenses</label>
    <label xml:lang="en-US" xlink:label="nktr_IncreaseDecreaseInAccruedClinicalTrialExpenses_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Increase Decrease In Accrued Clinical Trial Expenses</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInOtherAccruedLiabilities" xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInOtherAccruedLiabilities" />
    <label xml:lang="en-US" xlink:label="us-gaap_IncreaseDecreaseInOtherAccruedLiabilities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other accrued expenses</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInOtherAccruedLiabilities" xlink:to="us-gaap_IncreaseDecreaseInOtherAccruedLiabilities_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_IncreaseDecreaseInOtherAccruedLiabilities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Increase Decrease In Other Accrued Liabilities</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInInterestPayableNet" xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInInterestPayableNet" />
    <label xml:lang="en-US" xlink:label="us-gaap_IncreaseDecreaseInInterestPayableNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest payable</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInInterestPayableNet" xlink:to="us-gaap_IncreaseDecreaseInInterestPayableNet_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_IncreaseDecreaseInInterestPayableNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Increase Decrease In Interest Payable Net</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredRevenue" xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInDeferredRevenue" />
    <label xml:lang="en-US" xlink:label="us-gaap_IncreaseDecreaseInDeferredRevenue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred revenue</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInDeferredRevenue" xlink:to="us-gaap_IncreaseDecreaseInDeferredRevenue_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_IncreaseDecreaseInDeferredRevenue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Increase Decrease In Deferred Revenue</label>
    <label xml:lang="en-US" xlink:label="nktr_IncreaseDecreaseInMilestonePaymentLiabilities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Liability related to receipt of refundable milestone payment</label>
    <label xml:lang="en-US" xlink:label="nktr_IncreaseDecreaseInMilestonePaymentLiabilities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Increase Decrease In Milestone Payment Liabilities</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingLiabilities" xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingLiabilities" />
    <label xml:lang="en-US" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other liabilities</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInOtherOperatingLiabilities" xlink:to="us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Increase Decrease In Other Operating Liabilities</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" />
    <label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net cash used in operating activities</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Net Cash Provided By Used In Operating Activities Continuing Operations</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" />
    <label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash flows from investing activities:</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Net Cash Provided By Used In Investing Activities Continuing Operations [Abstract]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PaymentsToAcquireAvailableForSaleSecurities" xlink:type="locator" xlink:label="us-gaap_PaymentsToAcquireAvailableForSaleSecurities" />
    <label xml:lang="en-US" xlink:label="us-gaap_PaymentsToAcquireAvailableForSaleSecurities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Purchases of investments</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsToAcquireAvailableForSaleSecurities" xlink:to="us-gaap_PaymentsToAcquireAvailableForSaleSecurities_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_PaymentsToAcquireAvailableForSaleSecurities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Payments To Acquire Available For Sale Securities</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities" xlink:type="locator" xlink:label="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities" />
    <label xml:lang="en-US" xlink:label="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maturities of investments</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities" xlink:to="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities" xlink:type="locator" xlink:label="us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities" />
    <label xml:lang="en-US" xlink:label="us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Sales of investments</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities" xlink:to="us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds From Sale Of Available For Sale Securities</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncreaseDecreaseInRestrictedCash" xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInRestrictedCash" />
    <label xml:lang="en-US" xlink:label="us-gaap_IncreaseDecreaseInRestrictedCash_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Release of restricted cash</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInRestrictedCash" xlink:to="us-gaap_IncreaseDecreaseInRestrictedCash_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_IncreaseDecreaseInRestrictedCash_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Increase Decrease In Restricted Cash</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:type="locator" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" />
    <label xml:lang="en-US" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Purchases of property, plant and equipment</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:to="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Payments To Acquire Property Plant And Equipment</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" />
    <label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net cash (used in) provided by investing activities</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Net Cash Provided By Used In Investing Activities Continuing Operations</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" />
    <label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash flows from financing activities:</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Net Cash Provided By Used In Financing Activities Continuing Operations [Abstract]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepaymentsOfLongTermCapitalLeaseObligations" xlink:type="locator" xlink:label="us-gaap_RepaymentsOfLongTermCapitalLeaseObligations" />
    <label xml:lang="en-US" xlink:label="us-gaap_RepaymentsOfLongTermCapitalLeaseObligations_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Payment of capital lease obligations</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RepaymentsOfLongTermCapitalLeaseObligations" xlink:to="us-gaap_RepaymentsOfLongTermCapitalLeaseObligations_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_RepaymentsOfLongTermCapitalLeaseObligations_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Repayments Of Long Term Capital Lease Obligations</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProceedsFromIssuanceOfSecuredDebt" xlink:type="locator" xlink:label="us-gaap_ProceedsFromIssuanceOfSecuredDebt" />
    <label xml:lang="en-US" xlink:label="us-gaap_ProceedsFromIssuanceOfSecuredDebt_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Proceeds from issuance of 7.75% senior secured notes, net of issuance costs</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromIssuanceOfSecuredDebt" xlink:to="us-gaap_ProceedsFromIssuanceOfSecuredDebt_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_ProceedsFromIssuanceOfSecuredDebt_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds From Issuance Of Secured Debt</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepaymentsOfSeniorDebt" xlink:type="locator" xlink:label="us-gaap_RepaymentsOfSeniorDebt" />
    <label xml:lang="en-US" xlink:label="us-gaap_RepaymentsOfSeniorDebt_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Repayment of 12% senior secured notes</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RepaymentsOfSeniorDebt" xlink:to="us-gaap_RepaymentsOfSeniorDebt_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_RepaymentsOfSeniorDebt_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Repayments Of Senior Debt</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PaymentsOfDebtExtinguishmentCosts" xlink:type="locator" xlink:label="us-gaap_PaymentsOfDebtExtinguishmentCosts" />
    <label xml:lang="en-US" xlink:label="us-gaap_PaymentsOfDebtExtinguishmentCosts_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Payment of redemption premium and incremental interest on 12% senior secured notes</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsOfDebtExtinguishmentCosts" xlink:to="us-gaap_PaymentsOfDebtExtinguishmentCosts_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_PaymentsOfDebtExtinguishmentCosts_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Payments Of Debt Extinguishment Costs</label>
    <label xml:lang="en-US" xlink:label="nktr_RepaymentOfAndProceedsFromSaleOfFutureRoyaltiesNetOfTransactionCosts_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Repayment of proceeds from sale of future royalties</label>
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    <label xml:lang="en-US" xlink:label="nktr_ProceedsFromIssuanceOfCommonStockNetOfIssuanceCosts_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Issuance of common stock, net of issuance costs</label>
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents" xlink:type="locator" xlink:label="us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_InterestPaid" xlink:type="locator" xlink:label="us-gaap_InterestPaid" />
    <label xml:lang="en-US" xlink:label="us-gaap_InterestPaid_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash paid for interest</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestPaid" xlink:to="us-gaap_InterestPaid_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_InterestPaid_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Interest Paid</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_IncomeTaxesPaidNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash paid for income taxes</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxesPaidNet" xlink:to="us-gaap_IncomeTaxesPaidNet_lbl" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xlink:type="locator" xlink:label="us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" />
    <label xml:lang="en-US" xlink:label="us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Supplemental schedule of non-cash investing and financing activities:</label>
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    <label xml:lang="en-US" xlink:label="nktr_PropertyAndEquipmentAcquiredThroughCapitalLeasesAndOtherFinancing_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Property and equipment acquired through capital leases and other financing</label>
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentAxis" />
    <label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt Instrument</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument [Axis]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentNameDomain" />
    <label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentNameDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt Instrument Name</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentNameDomain" xlink:to="us-gaap_DebtInstrumentNameDomain_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentNameDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument Name [Domain]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_SevenPointSevenFivePercentSeniorSecuredNotesDueOctoberTwoThousandAndTwentyMember" xlink:type="locator" xlink:label="nktr_SevenPointSevenFivePercentSeniorSecuredNotesDueOctoberTwoThousandAndTwentyMember" />
    <label xml:lang="en-US" xlink:label="nktr_SevenPointSevenFivePercentSeniorSecuredNotesDueOctoberTwoThousandAndTwentyMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Seven point seven five percent senior secured notes due October two thousand and twenty.</label>
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    <label xml:lang="en-US" xlink:label="nktr_TwelvePercentSeniorSecuredNotesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Twelve percent senior secured notes.</label>
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    <label xml:lang="en-US" xlink:label="nktr_TwelvePercentSeniorSecuredNotesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">12% Senior Secured Notes [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_TwelvePercentSeniorSecuredNotesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Twelve Percent Senior Secured Notes [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentInterestRateStatedPercentage" />
    <label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentInterestRateStatedPercentage_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Senior secured notes, interest rate</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:to="us-gaap_DebtInstrumentInterestRateStatedPercentage_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentInterestRateStatedPercentage_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument Interest Rate Stated Percentage</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:type="locator" xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" />
    <label xml:lang="en-US" xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Organization Consolidation And Presentation Of Financial Statements [Abstract]</label>
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureAndSignificantAccountingPoliciesTextBlock" xlink:type="locator" xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureAndSignificantAccountingPoliciesTextBlock" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueDisclosuresTextBlock" xlink:type="locator" xlink:label="us-gaap_FairValueDisclosuresTextBlock" />
    <label xml:lang="en-US" xlink:label="us-gaap_FairValueDisclosuresTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash and Investments in Marketable Securities</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_FairValueDisclosuresTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Disclosures [Text Block]</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_InventoryDisclosureAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Inventory Disclosure [Abstract]</label>
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_InventoryDisclosureTextBlock" xlink:type="locator" xlink:label="us-gaap_InventoryDisclosureTextBlock" />
    <label xml:lang="en-US" xlink:label="us-gaap_InventoryDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Inventory</label>
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PropertyPlantAndEquipmentAbstract" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentAbstract" />
    <label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Property Plant And Equipment [Abstract]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentAbstract" xlink:to="us-gaap_PropertyPlantAndEquipmentAbstract_lbl" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock" />
    <label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Property, Plant and Equipment</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Property Plant And Equipment Disclosure [Text Block]</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_DebtDisclosureAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Debt Disclosure [Abstract]</label>
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LongTermDebtTextBlock" xlink:type="locator" xlink:label="us-gaap_LongTermDebtTextBlock" />
    <label xml:lang="en-US" xlink:label="us-gaap_LongTermDebtTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Senior Secured Notes</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_LongTermDebtTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Long Term Debt [Text Block]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LeasesAbstract" xlink:type="locator" xlink:label="us-gaap_LeasesAbstract" />
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LeasesOfLesseeDisclosureTextBlock" xlink:to="us-gaap_LeasesOfLesseeDisclosureTextBlock_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_LeasesOfLesseeDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Leases Of Lessee Disclosure [Text Block]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_LiabilityRelatedToSaleOfPotentialFutureRoyaltiesTextBlock" xlink:type="locator" xlink:label="nktr_LiabilityRelatedToSaleOfPotentialFutureRoyaltiesTextBlock" />
    <label xml:lang="en-US" xlink:label="nktr_LiabilityRelatedToSaleOfPotentialFutureRoyaltiesTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Liability related to sale of potential future royalties.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_LiabilityRelatedToSaleOfPotentialFutureRoyaltiesTextBlock" xlink:to="nktr_LiabilityRelatedToSaleOfPotentialFutureRoyaltiesTextBlock_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_LiabilityRelatedToSaleOfPotentialFutureRoyaltiesAbstract" xlink:type="locator" xlink:label="nktr_LiabilityRelatedToSaleOfPotentialFutureRoyaltiesAbstract" />
    <label xml:lang="en-US" xlink:label="nktr_LiabilityRelatedToSaleOfPotentialFutureRoyaltiesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Liability related to sale of potential future royalties.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_LiabilityRelatedToSaleOfPotentialFutureRoyaltiesAbstract" xlink:to="nktr_LiabilityRelatedToSaleOfPotentialFutureRoyaltiesAbstract_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_LiabilityRelatedToSaleOfPotentialFutureRoyaltiesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Liability Related To Sale Of Potential Future Royalties [Abstract]</label>
    <label xml:lang="en-US" xlink:label="nktr_LiabilityRelatedToSaleOfPotentialFutureRoyaltiesTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Liability Related to Sale of Future Royalties</label>
    <label xml:lang="en-US" xlink:label="nktr_LiabilityRelatedToSaleOfPotentialFutureRoyaltiesTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Liability Related To Sale Of Potential Future Royalties [Text Block]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CommitmentsAndContingenciesDisclosureAbstract" xlink:type="locator" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureAbstract" />
    <label xml:lang="en-US" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Commitments And Contingencies Disclosure [Abstract]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommitmentsAndContingenciesDisclosureAbstract" xlink:to="us-gaap_CommitmentsAndContingenciesDisclosureAbstract_lbl" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CommitmentsAndContingenciesDisclosureTextBlock" xlink:type="locator" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock" />
    <label xml:lang="en-US" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Commitments and Contingencies</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Commitments And Contingencies Disclosure [Text Block]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EquityAbstract" xlink:type="locator" xlink:label="us-gaap_EquityAbstract" />
    <label xml:lang="en-US" xlink:label="us-gaap_EquityAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Equity [Abstract]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EquityAbstract" xlink:to="us-gaap_EquityAbstract_lbl" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StockholdersEquityNoteDisclosureTextBlock" xlink:type="locator" xlink:label="us-gaap_StockholdersEquityNoteDisclosureTextBlock" />
    <label xml:lang="en-US" xlink:label="us-gaap_StockholdersEquityNoteDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stockholders&apos; Equity</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockholdersEquityNoteDisclosureTextBlock" xlink:to="us-gaap_StockholdersEquityNoteDisclosureTextBlock_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_StockholdersEquityNoteDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Stockholders Equity Note Disclosure [Text Block]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CollaborativeArrangementDisclosureTextBlock" xlink:type="locator" xlink:label="us-gaap_CollaborativeArrangementDisclosureTextBlock" />
    <label xml:lang="en-US" xlink:label="us-gaap_CollaborativeArrangementDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">License and Collaboration Agreements</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CollaborativeArrangementDisclosureTextBlock" xlink:to="us-gaap_CollaborativeArrangementDisclosureTextBlock_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_CollaborativeArrangementDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Collaborative Arrangement Disclosure [Text Block]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:type="locator" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" />
    <label xml:lang="en-US" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_lbl" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock" xlink:type="locator" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock" />
    <label xml:lang="en-US" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock-Based Compensation</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Disclosure Of Compensation Related Costs Share Based Payments [Text Block]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeTaxDisclosureAbstract" xlink:type="locator" xlink:label="us-gaap_IncomeTaxDisclosureAbstract" />
    <label xml:lang="en-US" xlink:label="us-gaap_IncomeTaxDisclosureAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Income Tax Disclosure [Abstract]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxDisclosureAbstract" xlink:to="us-gaap_IncomeTaxDisclosureAbstract_lbl" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeTaxDisclosureTextBlock" xlink:type="locator" xlink:label="us-gaap_IncomeTaxDisclosureTextBlock" />
    <label xml:lang="en-US" xlink:label="us-gaap_IncomeTaxDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income Taxes</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxDisclosureTextBlock" xlink:to="us-gaap_IncomeTaxDisclosureTextBlock_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_IncomeTaxDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Income Tax Disclosure [Text Block]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SegmentReportingAbstract" xlink:type="locator" xlink:label="us-gaap_SegmentReportingAbstract" />
    <label xml:lang="en-US" xlink:label="us-gaap_SegmentReportingAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting [Abstract]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SegmentReportingAbstract" xlink:to="us-gaap_SegmentReportingAbstract_lbl" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SegmentReportingDisclosureTextBlock" xlink:type="locator" xlink:label="us-gaap_SegmentReportingDisclosureTextBlock" />
    <label xml:lang="en-US" xlink:label="us-gaap_SegmentReportingDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Segment Reporting</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SegmentReportingDisclosureTextBlock" xlink:to="us-gaap_SegmentReportingDisclosureTextBlock_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_SegmentReportingDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting Disclosure [Text Block]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_QuarterlyFinancialInformationDisclosureAbstract" xlink:type="locator" xlink:label="us-gaap_QuarterlyFinancialInformationDisclosureAbstract" />
    <label xml:lang="en-US" xlink:label="us-gaap_QuarterlyFinancialInformationDisclosureAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Quarterly Financial Information Disclosure [Abstract]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_QuarterlyFinancialInformationDisclosureAbstract" xlink:to="us-gaap_QuarterlyFinancialInformationDisclosureAbstract_lbl" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_QuarterlyFinancialInformationTextBlock" xlink:type="locator" xlink:label="us-gaap_QuarterlyFinancialInformationTextBlock" />
    <label xml:lang="en-US" xlink:label="us-gaap_QuarterlyFinancialInformationTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Selected Quarterly Financial Data</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_QuarterlyFinancialInformationTextBlock" xlink:to="us-gaap_QuarterlyFinancialInformationTextBlock_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_QuarterlyFinancialInformationTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Quarterly Financial Information [Text Block]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_OrganizationPolicyTextBlock" xlink:type="locator" xlink:label="nktr_OrganizationPolicyTextBlock" />
    <label xml:lang="en-US" xlink:label="nktr_OrganizationPolicyTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Organization.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_OrganizationPolicyTextBlock" xlink:to="nktr_OrganizationPolicyTextBlock_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_OrganizationPolicyTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Organization</label>
    <label xml:lang="en-US" xlink:label="nktr_OrganizationPolicyTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Organization Policy [Text Block]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ConsolidationPolicyTextBlock" xlink:type="locator" xlink:label="us-gaap_ConsolidationPolicyTextBlock" />
    <label xml:lang="en-US" xlink:label="us-gaap_ConsolidationPolicyTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Basis of Presentation, Principles of Consolidation and Use of Estimates</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConsolidationPolicyTextBlock" xlink:to="us-gaap_ConsolidationPolicyTextBlock_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_ConsolidationPolicyTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Consolidation Policy [Text Block]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PriorPeriodReclassificationAdjustmentDescription" xlink:type="locator" xlink:label="us-gaap_PriorPeriodReclassificationAdjustmentDescription" />
    <label xml:lang="en-US" xlink:label="us-gaap_PriorPeriodReclassificationAdjustmentDescription_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reclassifications</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_PriorPeriodReclassificationAdjustmentDescription_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Prior Period Reclassification Adjustment Description</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CashAndCashEquivalentsPolicyTextBlock" xlink:type="locator" xlink:label="us-gaap_CashAndCashEquivalentsPolicyTextBlock" />
    <label xml:lang="en-US" xlink:label="us-gaap_CashAndCashEquivalentsPolicyTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash, Cash Equivalents, and Investments, and Fair Value of Financial Instruments</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CashAndCashEquivalentsPolicyTextBlock" xlink:to="us-gaap_CashAndCashEquivalentsPolicyTextBlock_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_CashAndCashEquivalentsPolicyTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Cash And Cash Equivalents Policy [Text Block]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_AccountsReceivableAndSignificantCustomerConcentrationsPolicyPolicyTextBlock" xlink:type="locator" xlink:label="nktr_AccountsReceivableAndSignificantCustomerConcentrationsPolicyPolicyTextBlock" />
    <label xml:lang="en-US" xlink:label="nktr_AccountsReceivableAndSignificantCustomerConcentrationsPolicyPolicyTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Accounts receivable and significant customer concentrations.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_AccountsReceivableAndSignificantCustomerConcentrationsPolicyPolicyTextBlock" xlink:to="nktr_AccountsReceivableAndSignificantCustomerConcentrationsPolicyPolicyTextBlock_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_AccountsReceivableAndSignificantCustomerConcentrationsPolicyPolicyTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accounts Receivable and Significant Customer Concentrations</label>
    <label xml:lang="en-US" xlink:label="nktr_AccountsReceivableAndSignificantCustomerConcentrationsPolicyPolicyTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Accounts Receivable And Significant Customer Concentrations Policy Policy [Text Block]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_InventoryAndSignificantSupplierConcentrationsPolicyTextBlock" xlink:type="locator" xlink:label="nktr_InventoryAndSignificantSupplierConcentrationsPolicyTextBlock" />
    <label xml:lang="en-US" xlink:label="nktr_InventoryAndSignificantSupplierConcentrationsPolicyTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Inventory and significant supplier concentrations.</label>
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    <label xml:lang="en-US" xlink:label="nktr_InventoryAndSignificantSupplierConcentrationsPolicyTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Inventory and Significant Supplier Concentrations</label>
    <label xml:lang="en-US" xlink:label="nktr_InventoryAndSignificantSupplierConcentrationsPolicyTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Inventory And Significant Supplier Concentrations Policy [Text Block]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" />
    <label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Long-Lived Assets</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xlink:to="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Property Plant And Equipment Policy [Text Block]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RevenueRecognitionPolicyTextBlock" xlink:type="locator" xlink:label="us-gaap_RevenueRecognitionPolicyTextBlock" />
    <label xml:lang="en-US" xlink:label="us-gaap_RevenueRecognitionPolicyTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Revenue Recognition</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_RevenueRecognitionPolicyTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Revenue Recognition Policy [Text Block]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShippingAndHandlingCostPolicyTextBlock" xlink:type="locator" xlink:label="us-gaap_ShippingAndHandlingCostPolicyTextBlock" />
    <label xml:lang="en-US" xlink:label="us-gaap_ShippingAndHandlingCostPolicyTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Shipping and Handling Costs</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_ShippingAndHandlingCostPolicyTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Shipping And Handling Cost Policy [Text Block]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ResearchAndDevelopmentExpensePolicy" xlink:type="locator" xlink:label="us-gaap_ResearchAndDevelopmentExpensePolicy" />
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    <loc xlink:href="nktr-20151231.xsd#nktr_ScheduleOfLiabilityRelatedToSaleOfPotentialFutureRoyaltiesTableTextBlock" xlink:type="locator" xlink:label="nktr_ScheduleOfLiabilityRelatedToSaleOfPotentialFutureRoyaltiesTableTextBlock" />
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    <loc xlink:href="nktr-20151231.xsd#nktr_SharesOfCommonStockForIssuanceUnderExistingEquityCompensationPlansTableTextBlock" xlink:type="locator" xlink:label="nktr_SharesOfCommonStockForIssuanceUnderExistingEquityCompensationPlansTableTextBlock" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock" xlink:type="locator" xlink:label="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock" />
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    <loc xlink:href="nktr-20151231.xsd#nktr_IncomeLossBeforeProvisionForIncomeTaxesTableTextBlock" xlink:type="locator" xlink:label="nktr_IncomeLossBeforeProvisionForIncomeTaxesTableTextBlock" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfRevenueFromExternalCustomersAttributedToForeignCountriesByGeographicAreaTextBlock" xlink:type="locator" xlink:label="us-gaap_ScheduleOfRevenueFromExternalCustomersAttributedToForeignCountriesByGeographicAreaTextBlock" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfQuarterlyFinancialInformationTableTextBlock" xlink:type="locator" xlink:label="us-gaap_ScheduleOfQuarterlyFinancialInformationTableTextBlock" />
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    <loc xlink:href="nktr-20151231.xsd#nktr_CashRestrictedCashCashEquivalentsAndAvailableForSaleInvestments" xlink:type="locator" xlink:label="nktr_CashRestrictedCashCashEquivalentsAndAvailableForSaleInvestments" />
    <label xml:lang="en-US" xlink:label="nktr_CashRestrictedCashCashEquivalentsAndAvailableForSaleInvestments_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Cash, restricted cash, cash equivalents, and available for sale investments.</label>
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    <loc xlink:href="nktr-20151231.xsd#nktr_OrganizationAndSummaryOfSignificantAccountingPoliciesLineItems" xlink:type="locator" xlink:label="nktr_OrganizationAndSummaryOfSignificantAccountingPoliciesLineItems" />
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    <loc xlink:href="nktr-20151231.xsd#nktr_OrganizationAndSummaryOfSignificantAccountingPoliciesTable" xlink:type="locator" xlink:label="nktr_OrganizationAndSummaryOfSignificantAccountingPoliciesTable" />
    <label xml:lang="en-US" xlink:label="nktr_OrganizationAndSummaryOfSignificantAccountingPoliciesTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Organization and summary of significant accounting policies.</label>
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RangeAxis" xlink:type="locator" xlink:label="us-gaap_RangeAxis" />
    <label xml:lang="en-US" xlink:label="us-gaap_RangeAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Range</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_RangeAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Range [Axis]</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_RangeMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Range Member</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_RangeMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Range [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_MinimumMember" xlink:type="locator" xlink:label="us-gaap_MinimumMember" />
    <label xml:lang="en-US" xlink:label="us-gaap_MinimumMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Minimum [Member]</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_MinimumMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Minimum [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_MaximumMember" xlink:type="locator" xlink:label="us-gaap_MaximumMember" />
    <label xml:lang="en-US" xlink:label="us-gaap_MaximumMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maximum [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MaximumMember" xlink:to="us-gaap_MaximumMember_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_MaximumMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Maximum [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:type="locator" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:type="locator" xlink:label="us-gaap_AntidilutiveSecuritiesNameDomain" />
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    <loc xlink:href="nktr-20151231.xsd#nktr_StockOptionsAndRestrictedStockUnitsMember" xlink:type="locator" xlink:label="nktr_StockOptionsAndRestrictedStockUnitsMember" />
    <label xml:lang="en-US" xlink:label="nktr_StockOptionsAndRestrictedStockUnitsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Stock options and restricted stock units.</label>
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    <label xml:lang="en-US" xlink:label="nktr_OrganizationAndSummaryOfSignificantAccountingPoliciesLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Organization And Summary Of Significant Accounting Policies [Line Items]</label>
    <label xml:lang="en-US" xlink:label="nktr_CashRestrictedCashCashEquivalentsAndAvailableForSaleInvestments_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash and investments in marketable securities</label>
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SeniorNotes" xlink:type="locator" xlink:label="us-gaap_SeniorNotes" />
    <label xml:lang="en-US" xlink:label="us-gaap_SeniorNotes_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Senior secured notes</label>
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtAndCapitalLeaseObligations" xlink:type="locator" xlink:label="us-gaap_DebtAndCapitalLeaseObligations" />
    <label xml:lang="en-US" xlink:label="us-gaap_DebtAndCapitalLeaseObligations_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt and capital lease obligation</label>
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CapitalLeaseObligations" xlink:type="locator" xlink:label="us-gaap_CapitalLeaseObligations" />
    <label xml:lang="en-US" xlink:label="us-gaap_CapitalLeaseObligations_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Capital lease obligations</label>
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    <loc xlink:href="nktr-20151231.xsd#nktr_NumberOfCustomersAccountedForMajorAccountsReceivable" xlink:type="locator" xlink:label="nktr_NumberOfCustomersAccountedForMajorAccountsReceivable" />
    <label xml:lang="en-US" xlink:label="nktr_NumberOfCustomersAccountedForMajorAccountsReceivable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Number of customers accounted for major accounts receivable.</label>
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    <loc xlink:href="nktr-20151231.xsd#nktr_PercentageOfAccountsReceivableCustomersOne" xlink:type="locator" xlink:label="nktr_PercentageOfAccountsReceivableCustomersOne" />
    <label xml:lang="en-US" xlink:label="nktr_PercentageOfAccountsReceivableCustomersOne_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Percentage of accounts receivable customers one.</label>
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    <label xml:lang="en-US" xlink:label="nktr_PercentageOfAccountsReceivableCustomersTwo_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Percentage Of Accounts Receivable Customers Two</label>
    <label xml:lang="en-US" xlink:label="nktr_PercentageOfAccountsReceivableCustomersThree_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage of accounts receivable customers three</label>
    <label xml:lang="en-US" xlink:label="nktr_PercentageOfAccountsReceivableCustomersThree_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Percentage Of Accounts Receivable Customers Three</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife" />
    <label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Property and equipment estimated useful lives</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Property Plant And Equipment Useful Life</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_NumberOfReportingUnitsToEvaluateGoodwillForImpairment" xlink:type="locator" xlink:label="nktr_NumberOfReportingUnitsToEvaluateGoodwillForImpairment" />
    <label xml:lang="en-US" xlink:label="nktr_NumberOfReportingUnitsToEvaluateGoodwillForImpairment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Number of reporting units to evaluate goodwill for impairment</label>
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AssetImpairmentCharges" xlink:type="locator" xlink:label="us-gaap_AssetImpairmentCharges" />
    <label xml:lang="en-US" xlink:label="us-gaap_AssetImpairmentCharges_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Asset impairment charges</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_AssetImpairmentCharges_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Asset Impairment Charges</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:type="locator" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" />
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    <loc xlink:href="nktr-20151231.xsd#nktr_PercentageOfAmountRealizedUponUltimateSettlement" xlink:type="locator" xlink:label="nktr_PercentageOfAmountRealizedUponUltimateSettlement" />
    <label xml:lang="en-US" xlink:label="nktr_PercentageOfAmountRealizedUponUltimateSettlement_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Percentage of amount realized upon ultimate settlement.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_PercentageOfAmountRealizedUponUltimateSettlement" xlink:to="nktr_PercentageOfAmountRealizedUponUltimateSettlement_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_PercentageOfAmountRealizedUponUltimateSettlement_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Minimum percentage of amount realized upon ultimate settlement</label>
    <label xml:lang="en-US" xlink:label="nktr_PercentageOfAmountRealizedUponUltimateSettlement_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Percentage Of Amount Realized Upon Ultimate Settlement</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract" xlink:type="locator" xlink:label="us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract" />
    <label xml:lang="en-US" xlink:label="us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]</label>
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    <label xml:lang="en-US" xlink:label="nktr_CashRestrictedCashCashEquivalentsAndAvailableForSaleInvestments_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total cash and investments in marketable securities</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_DebtInvestmentMaximumMaturityPeriod" xlink:type="locator" xlink:label="nktr_DebtInvestmentMaximumMaturityPeriod" />
    <label xml:lang="en-US" xlink:label="nktr_DebtInvestmentMaximumMaturityPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Debt investment maximum maturity period.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_DebtInvestmentMaximumMaturityPeriod" xlink:to="nktr_DebtInvestmentMaximumMaturityPeriod_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_DebtInvestmentMaturityDateDescription" xlink:type="locator" xlink:label="nktr_DebtInvestmentMaturityDateDescription" />
    <label xml:lang="en-US" xlink:label="nktr_DebtInvestmentMaturityDateDescription_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Debt investment maturity date description.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_DebtInvestmentMaturityDateDescription" xlink:to="nktr_DebtInvestmentMaturityDateDescription_lbl" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CashAndCashEquivalentsAbstract" xlink:type="locator" xlink:label="us-gaap_CashAndCashEquivalentsAbstract" />
    <label xml:lang="en-US" xlink:label="us-gaap_CashAndCashEquivalentsAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Cash And Cash Equivalents [Abstract]</label>
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    <loc xlink:href="nktr-20151231.xsd#nktr_CashAndInvestmentsInMarketableSecuritiesLineItems" xlink:type="locator" xlink:label="nktr_CashAndInvestmentsInMarketableSecuritiesLineItems" />
    <label xml:lang="en-US" xlink:label="nktr_CashAndInvestmentsInMarketableSecuritiesLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Cash and Investments in Marketable Securities [Line Items]</label>
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    <loc xlink:href="nktr-20151231.xsd#nktr_CashAndInvestmentsInMarketableSecuritiesTable" xlink:type="locator" xlink:label="nktr_CashAndInvestmentsInMarketableSecuritiesTable" />
    <label xml:lang="en-US" xlink:label="nktr_CashAndInvestmentsInMarketableSecuritiesTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Cash and Investments in Marketable Securities [Table]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_CashAndInvestmentsInMarketableSecuritiesTable" xlink:to="nktr_CashAndInvestmentsInMarketableSecuritiesTable_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_CashAndInvestmentsInMarketableSecuritiesTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash And Investments In Marketable Securities [Table]</label>
    <label xml:lang="en-US" xlink:label="nktr_CashAndInvestmentsInMarketableSecuritiesTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Cash And Investments In Marketable Securities [Table]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:type="locator" xlink:label="us-gaap_LongtermDebtTypeAxis" />
    <label xml:lang="en-US" xlink:label="us-gaap_LongtermDebtTypeAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Longterm Debt Type</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_LongtermDebtTypeAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Longterm Debt Type [Axis]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:type="locator" xlink:label="us-gaap_LongtermDebtTypeDomain" />
    <label xml:lang="en-US" xlink:label="us-gaap_LongtermDebtTypeDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Longterm Debt Type</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_LongtermDebtTypeDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Longterm Debt Type [Domain]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SeniorNotesMember" xlink:type="locator" xlink:label="us-gaap_SeniorNotesMember" />
    <label xml:lang="en-US" xlink:label="us-gaap_SeniorNotesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Senior Notes [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SeniorNotesMember" xlink:to="us-gaap_SeniorNotesMember_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_SeniorNotesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Senior Notes [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_TwelvePercentSeniorSecuredNotesDueJulyTwoThousandAndSeventeenMember" xlink:type="locator" xlink:label="nktr_TwelvePercentSeniorSecuredNotesDueJulyTwoThousandAndSeventeenMember" />
    <label xml:lang="en-US" xlink:label="nktr_TwelvePercentSeniorSecuredNotesDueJulyTwoThousandAndSeventeenMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">12% senior secured notes due July 2017.</label>
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    <label xml:lang="en-US" xlink:label="nktr_SevenPointSevenFivePercentSeniorSecuredNotesDueOctoberTwoThousandAndTwentyMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">7.75% Senior Secured Notes Due October 2020 [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_CashAndInvestmentsInMarketableSecuritiesLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash and Investments in Marketable Securities [Line Items]</label>
    <label xml:lang="en-US" xlink:label="nktr_CashAndInvestmentsInMarketableSecuritiesLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Cash And Investments In Marketable Securities [Line Items]</label>
    <label xml:lang="en-US" xlink:label="nktr_DebtInvestmentMaximumMaturityPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maximum maturity term for debt securities investment</label>
    <label xml:lang="en-US" xlink:label="nktr_DebtInvestmentMaximumMaturityPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Debt Investment Maximum Maturity Period</label>
    <label xml:lang="en-US" xlink:label="nktr_DebtInvestmentMaturityDateDescription_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted average maturity term for debt securities investment</label>
    <label xml:lang="en-US" xlink:label="nktr_DebtInvestmentMaturityDateDescription_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Debt Investment Maturity Date Description</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AvailableForSaleSecuritiesGrossRealizedGainsLossesSaleProceeds" xlink:type="locator" xlink:label="us-gaap_AvailableForSaleSecuritiesGrossRealizedGainsLossesSaleProceeds" />
    <label xml:lang="en-US" xlink:label="us-gaap_AvailableForSaleSecuritiesGrossRealizedGainsLossesSaleProceeds_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale securities, sold</label>
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    <loc xlink:href="nktr-20151231.xsd#nktr_MinimumCashAndInvestmentsInMarketableSecuritiesToBeMaintained" xlink:type="locator" xlink:label="nktr_MinimumCashAndInvestmentsInMarketableSecuritiesToBeMaintained" />
    <label xml:lang="en-US" xlink:label="nktr_MinimumCashAndInvestmentsInMarketableSecuritiesToBeMaintained_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Minimum cash and investments in marketable securities to be maintained.</label>
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtInstrumentMaturityDate" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentMaturityDate" />
    <label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentMaturityDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Senior secured notes, maturity date</label>
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    <label xml:lang="en-US" xlink:label="nktr_MinimumCashAndInvestmentsInMarketableSecuritiesToBeMaintained_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Minimum Cash And Investments In Marketable Securities To Be Maintained</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_CashAndRestrictedCash" xlink:type="locator" xlink:label="nktr_CashAndRestrictedCash" />
    <label xml:lang="en-US" xlink:label="nktr_CashAndRestrictedCash_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Cash And Restricted Cash</label>
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:type="locator" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_InvestmentTypeAxis" xlink:type="locator" xlink:label="us-gaap_InvestmentTypeAxis" />
    <label xml:lang="en-US" xlink:label="us-gaap_InvestmentTypeAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Investment Type</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Property Plant And Equipment Type</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="us-gaap_PropertyPlantAndEquipmentTypeDomain_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Property Plant And Equipment Type [Domain]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_BuildingAndLeaseholdImprovementsMember" xlink:type="locator" xlink:label="nktr_BuildingAndLeaseholdImprovementsMember" />
    <label xml:lang="en-US" xlink:label="nktr_BuildingAndLeaseholdImprovementsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Building and Leasehold Improvements.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_BuildingAndLeaseholdImprovementsMember" xlink:to="nktr_BuildingAndLeaseholdImprovementsMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_BuildingAndLeaseholdImprovementsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Building and Leasehold Improvements [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_BuildingAndLeaseholdImprovementsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Building And Leasehold Improvements [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_LaboratoryEquipmentMember" xlink:type="locator" xlink:label="nktr_LaboratoryEquipmentMember" />
    <label xml:lang="en-US" xlink:label="nktr_LaboratoryEquipmentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Laboratory equipment.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_LaboratoryEquipmentMember" xlink:to="nktr_LaboratoryEquipmentMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_LaboratoryEquipmentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Laboratory Equipment [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_LaboratoryEquipmentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Laboratory Equipment [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ManufacturingFacilityMember" xlink:type="locator" xlink:label="us-gaap_ManufacturingFacilityMember" />
    <label xml:lang="en-US" xlink:label="us-gaap_ManufacturingFacilityMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Manufacturing Equipment [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ManufacturingFacilityMember" xlink:to="us-gaap_ManufacturingFacilityMember_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_ManufacturingFacilityMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Manufacturing Facility [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_FurnitureAndFixturesMember" xlink:type="locator" xlink:label="us-gaap_FurnitureAndFixturesMember" />
    <label xml:lang="en-US" xlink:label="us-gaap_FurnitureAndFixturesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Furniture, Fixtures and Other Equipment [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FurnitureAndFixturesMember" xlink:to="us-gaap_FurnitureAndFixturesMember_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_FurnitureAndFixturesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Furniture And Fixtures [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentLineItems" />
    <label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Property, Plant and Equipment [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentLineItems" xlink:to="us-gaap_PropertyPlantAndEquipmentLineItems_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Property Plant And Equipment [Line Items]</label>
    <label xml:lang="en-US" xlink:label="nktr_DepreciablePropertyPlantAndEquipmentGross_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Depreciable property and equipment at cost</label>
    <label xml:lang="en-US" xlink:label="nktr_DepreciablePropertyPlantAndEquipmentGross_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Depreciable Property Plant And Equipment Gross</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:type="locator" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" />
    <label xml:lang="en-US" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Less: accumulated depreciation</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:to="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Accumulated Depreciation Depletion And Amortization Property Plant And Equipment</label>
    <label xml:lang="en-US" xlink:label="nktr_DepreciablePropertyPlantAndEquipmentNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Depreciable property, plant and equipment, net</label>
    <label xml:lang="en-US" xlink:label="nktr_DepreciablePropertyPlantAndEquipmentNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Depreciable Property Plant And Equipment Net</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ConstructionInProgressGross" xlink:type="locator" xlink:label="us-gaap_ConstructionInProgressGross" />
    <label xml:lang="en-US" xlink:label="us-gaap_ConstructionInProgressGross_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Construction-in-progress</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConstructionInProgressGross" xlink:to="us-gaap_ConstructionInProgressGross_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_ConstructionInProgressGross_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Construction In Progress Gross</label>
    <label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Property plant and equipment, net</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_EquipmentPurchaseObligationPayableTerm" xlink:type="locator" xlink:label="nktr_EquipmentPurchaseObligationPayableTerm" />
    <label xml:lang="en-US" xlink:label="nktr_EquipmentPurchaseObligationPayableTerm_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Equipment purchase obligation payable term.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_EquipmentPurchaseObligationPayableTerm" xlink:to="nktr_EquipmentPurchaseObligationPayableTerm_lbl" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PurchaseObligation" xlink:type="locator" xlink:label="us-gaap_PurchaseObligation" />
    <label xml:lang="en-US" xlink:label="us-gaap_PurchaseObligation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Obligation related to purchase of equipment</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PurchaseObligation" xlink:to="us-gaap_PurchaseObligation_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_PurchaseObligation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Purchase Obligation</label>
    <label xml:lang="en-US" xlink:label="nktr_EquipmentPurchaseObligationPayableTerm_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Obligation related to purchase of equipment liability payable term</label>
    <label xml:lang="en-US" xlink:label="nktr_EquipmentPurchaseObligationPayableTerm_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Equipment Purchase Obligation Payable Term</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_Depreciation" xlink:type="locator" xlink:label="us-gaap_Depreciation" />
    <label xml:lang="en-US" xlink:label="us-gaap_Depreciation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Depreciation expense</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Depreciation" xlink:to="us-gaap_Depreciation_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_Depreciation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Depreciation</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_SeniorSecuredDebtAbstract" xlink:type="locator" xlink:label="nktr_SeniorSecuredDebtAbstract" />
    <label xml:lang="en-US" xlink:label="nktr_SeniorSecuredDebtAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Senior Secured Debt [Abstract]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_SeniorSecuredDebtAbstract" xlink:to="nktr_SeniorSecuredDebtAbstract_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_SeniorSecuredDebtAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Senior Secured Debt [Abstract]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LineOfCreditFacilityTable" xlink:type="locator" xlink:label="us-gaap_LineOfCreditFacilityTable" />
    <label xml:lang="en-US" xlink:label="us-gaap_LineOfCreditFacilityTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Line Of Credit Facility [Table]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityTable" xlink:to="us-gaap_LineOfCreditFacilityTable_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_LineOfCreditFacilityTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Line Of Credit Facility [Table]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LineOfCreditFacilityLineItems" xlink:type="locator" xlink:label="us-gaap_LineOfCreditFacilityLineItems" />
    <label xml:lang="en-US" xlink:label="us-gaap_LineOfCreditFacilityLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Line of Credit Facility [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityLineItems" xlink:to="us-gaap_LineOfCreditFacilityLineItems_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_LineOfCreditFacilityLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Line Of Credit Facility [Line Items]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentFaceAmount" />
    <label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentFaceAmount_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Senior secured notes, issued</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentFaceAmount" xlink:to="us-gaap_DebtInstrumentFaceAmount_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentFaceAmount_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument Face Amount</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtInstrumentFrequencyOfPeriodicPayment" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentFrequencyOfPeriodicPayment" />
    <label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentFrequencyOfPeriodicPayment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Frequency of payment</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentFrequencyOfPeriodicPayment" xlink:to="us-gaap_DebtInstrumentFrequencyOfPeriodicPayment_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentFrequencyOfPeriodicPayment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument Frequency Of Periodic Payment</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtInstrumentDateOfFirstRequiredPayment1" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentDateOfFirstRequiredPayment1" />
    <label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentDateOfFirstRequiredPayment1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Date of first repayment</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentDateOfFirstRequiredPayment1" xlink:to="us-gaap_DebtInstrumentDateOfFirstRequiredPayment1_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentDateOfFirstRequiredPayment1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument Date Of First Required Payment1</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_DebtDiscountOnTransactionAndFacilityFeesPaid" xlink:type="locator" xlink:label="nktr_DebtDiscountOnTransactionAndFacilityFeesPaid" />
    <label xml:lang="en-US" xlink:label="nktr_DebtDiscountOnTransactionAndFacilityFeesPaid_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Debt discount on transaction and facility fees paid.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_DebtDiscountOnTransactionAndFacilityFeesPaid" xlink:to="nktr_DebtDiscountOnTransactionAndFacilityFeesPaid_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_DirectDebtIssuanceCostsCapitalized" xlink:type="locator" xlink:label="nktr_DirectDebtIssuanceCostsCapitalized" />
    <label xml:lang="en-US" xlink:label="nktr_DirectDebtIssuanceCostsCapitalized_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Direct debt issuance costs capitalized.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_DirectDebtIssuanceCostsCapitalized" xlink:to="nktr_DirectDebtIssuanceCostsCapitalized_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_AdditionalDebtIssuanceCosts" xlink:type="locator" xlink:label="nktr_AdditionalDebtIssuanceCosts" />
    <label xml:lang="en-US" xlink:label="nktr_AdditionalDebtIssuanceCosts_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Additional debt issuance costs.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_AdditionalDebtIssuanceCosts" xlink:to="nktr_AdditionalDebtIssuanceCosts_lbl" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtIssuanceCosts" xlink:type="locator" xlink:label="us-gaap_DebtIssuanceCosts" />
    <label xml:lang="en-US" xlink:label="us-gaap_DebtIssuanceCosts_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Issuance costs</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtIssuanceCosts" xlink:to="us-gaap_DebtIssuanceCosts_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_DebtIssuanceCosts_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Debt Issuance Costs</label>
    <label xml:lang="en-US" xlink:label="nktr_DebtDiscountOnTransactionAndFacilityFeesPaid_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt discount on transaction and facility fees</label>
    <label xml:lang="en-US" xlink:label="nktr_DebtDiscountOnTransactionAndFacilityFeesPaid_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Debt Discount On Transaction And Facility Fees Paid</label>
    <label xml:lang="en-US" xlink:label="nktr_DirectDebtIssuanceCostsCapitalized_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Direct debt issuance costs capitalized</label>
    <label xml:lang="en-US" xlink:label="nktr_DirectDebtIssuanceCostsCapitalized_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Direct Debt Issuance Costs Capitalized</label>
    <label xml:lang="en-US" xlink:label="nktr_AdditionalDebtIssuanceCosts_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Additional issuance costs</label>
    <label xml:lang="en-US" xlink:label="nktr_AdditionalDebtIssuanceCosts_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Additional Debt Issuance Costs</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DebtInstrumentTerm" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentTerm" />
    <label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentTerm_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt instrument term</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentTerm" xlink:to="us-gaap_DebtInstrumentTerm_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_DebtInstrumentTerm_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument Term</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_AccruedInterestPaidOnSeniorSecuredNotesAtRedemption" xlink:type="locator" xlink:label="nktr_AccruedInterestPaidOnSeniorSecuredNotesAtRedemption" />
    <label xml:lang="en-US" xlink:label="nktr_AccruedInterestPaidOnSeniorSecuredNotesAtRedemption_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Accrued interest paid on senior secured notes at redemption.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_AccruedInterestPaidOnSeniorSecuredNotesAtRedemption" xlink:to="nktr_AccruedInterestPaidOnSeniorSecuredNotesAtRedemption_lbl" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RepaymentsOfDebt" xlink:type="locator" xlink:label="us-gaap_RepaymentsOfDebt" />
    <label xml:lang="en-US" xlink:label="us-gaap_RepaymentsOfDebt_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Repayment of senior secured notes</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RepaymentsOfDebt" xlink:to="us-gaap_RepaymentsOfDebt_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_RepaymentsOfDebt_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Repayments Of Debt</label>
    <label xml:lang="en-US" xlink:label="nktr_AccruedInterestPaidOnSeniorSecuredNotesAtRedemption_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accrued interest paid on 12% notes at redemption</label>
    <label xml:lang="en-US" xlink:label="nktr_AccruedInterestPaidOnSeniorSecuredNotesAtRedemption_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Accrued Interest Paid On Senior Secured Notes At Redemption</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RedemptionPremium" xlink:type="locator" xlink:label="us-gaap_RedemptionPremium" />
    <label xml:lang="en-US" xlink:label="us-gaap_RedemptionPremium_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Redemption premium</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RedemptionPremium" xlink:to="us-gaap_RedemptionPremium_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_RedemptionPremium_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Redemption Premium</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProceedsFromIssuanceOfDebt" xlink:type="locator" xlink:label="us-gaap_ProceedsFromIssuanceOfDebt" />
    <label xml:lang="en-US" xlink:label="us-gaap_ProceedsFromIssuanceOfDebt_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Senior secured notes, cash received</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromIssuanceOfDebt" xlink:to="us-gaap_ProceedsFromIssuanceOfDebt_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_ProceedsFromIssuanceOfDebt_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds From Issuance Of Debt</label>
    <label xml:lang="en-US" xlink:label="us-gaap_GainsLossesOnExtinguishmentOfDebt_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Loss on extinguishment of debt</label>
    <label xml:lang="en-US" xlink:label="us-gaap_WriteOffOfDeferredDebtIssuanceCost_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Write-off of unamortized issuance costs</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_RestrictedCashSubsequentlyReleased" xlink:type="locator" xlink:label="nktr_RestrictedCashSubsequentlyReleased" />
    <label xml:lang="en-US" xlink:label="nktr_RestrictedCashSubsequentlyReleased_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Restricted cash subsequently released.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_RestrictedCashSubsequentlyReleased" xlink:to="nktr_RestrictedCashSubsequentlyReleased_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_RedemptionPriceAsPercentageOfPrincipalAmountInCaseOfChangeOfControl" xlink:type="locator" xlink:label="nktr_RedemptionPriceAsPercentageOfPrincipalAmountInCaseOfChangeOfControl" />
    <label xml:lang="en-US" xlink:label="nktr_RedemptionPriceAsPercentageOfPrincipalAmountInCaseOfChangeOfControl_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Redemption price as percentage of principal amount in case of change of control.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_RedemptionPriceAsPercentageOfPrincipalAmountInCaseOfChangeOfControl" xlink:to="nktr_RedemptionPriceAsPercentageOfPrincipalAmountInCaseOfChangeOfControl_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_RedemptionPriceAsPercentageOfPrincipalAmountInCaseOfSaleOfAssets" xlink:type="locator" xlink:label="nktr_RedemptionPriceAsPercentageOfPrincipalAmountInCaseOfSaleOfAssets" />
    <label xml:lang="en-US" xlink:label="nktr_RedemptionPriceAsPercentageOfPrincipalAmountInCaseOfSaleOfAssets_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Redemption price as percentage of principal amount in case of sale of assets.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_RedemptionPriceAsPercentageOfPrincipalAmountInCaseOfSaleOfAssets" xlink:to="nktr_RedemptionPriceAsPercentageOfPrincipalAmountInCaseOfSaleOfAssets_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_RestrictedCashSubsequentlyReleased_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Restricted cash to be maintained until release of 12% Notes liens</label>
    <label xml:lang="en-US" xlink:label="nktr_RestrictedCashSubsequentlyReleased_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Restricted Cash Subsequently Released</label>
    <label xml:lang="en-US" xlink:label="nktr_RedemptionPriceAsPercentageOfPrincipalAmountInCaseOfChangeOfControl_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage of repurchase of notes on principal amount of notes</label>
    <label xml:lang="en-US" xlink:label="nktr_RedemptionPriceAsPercentageOfPrincipalAmountInCaseOfChangeOfControl_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Redemption Price As Percentage Of Principal Amount In Case Of Change Of Control</label>
    <label xml:lang="en-US" xlink:label="nktr_RedemptionPriceAsPercentageOfPrincipalAmountInCaseOfSaleOfAssets_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage of repurchase of notes on principal amount of notes upon sale of assets</label>
    <label xml:lang="en-US" xlink:label="nktr_RedemptionPriceAsPercentageOfPrincipalAmountInCaseOfSaleOfAssets_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Redemption Price As Percentage Of Principal Amount In Case Of Sale Of Assets</label>
    <label xml:lang="en-US" xlink:label="us-gaap_SeniorNotes_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Senior Secured Notes principal amount</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_PercentageCeilingOnRentIncrease" xlink:type="locator" xlink:label="nktr_PercentageCeilingOnRentIncrease" />
    <label xml:lang="en-US" xlink:label="nktr_PercentageCeilingOnRentIncrease_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Percentage ceiling on rent increase.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_PercentageCeilingOnRentIncrease" xlink:to="nktr_PercentageCeilingOnRentIncrease_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_CapitalLeasesTerminationDate" xlink:type="locator" xlink:label="nktr_CapitalLeasesTerminationDate" />
    <label xml:lang="en-US" xlink:label="nktr_CapitalLeasesTerminationDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Capital leases termination date.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_CapitalLeasesTerminationDate" xlink:to="nktr_CapitalLeasesTerminationDate_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_LeasesLineItems" xlink:type="locator" xlink:label="nktr_LeasesLineItems" />
    <label xml:lang="en-US" xlink:label="nktr_LeasesLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Leases [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_LeasesLineItems" xlink:to="nktr_LeasesLineItems_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_ScheduleOfLeasesTable" xlink:type="locator" xlink:label="nktr_ScheduleOfLeasesTable" />
    <label xml:lang="en-US" xlink:label="nktr_ScheduleOfLeasesTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Schedule Of Leases [Table]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_ScheduleOfLeasesTable" xlink:to="nktr_ScheduleOfLeasesTable_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_ScheduleOfLeasesTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Leases [Table]</label>
    <label xml:lang="en-US" xlink:label="nktr_ScheduleOfLeasesTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Schedule Of Leases [Table]</label>
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:type="locator" xlink:label="dei_LegalEntityAxis" />
    <label xml:lang="en-US" xlink:label="dei_LegalEntityAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Legal Entity</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_LegalEntityAxis" xlink:to="dei_LegalEntityAxis_lbl" />
    <label xml:lang="en-US" xlink:label="dei_LegalEntityAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Legal Entity [Axis]</label>
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:type="locator" xlink:label="dei_EntityDomain" />
    <label xml:lang="en-US" xlink:label="dei_EntityDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityDomain" xlink:to="dei_EntityDomain_lbl" />
    <label xml:lang="en-US" xlink:label="dei_EntityDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity [Domain]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_PfizerMember" xlink:type="locator" xlink:label="nktr_PfizerMember" />
    <label xml:lang="en-US" xlink:label="nktr_PfizerMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Pfizer.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_PfizerMember" xlink:to="nktr_PfizerMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_PfizerMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Pfizer, Inc. [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_PfizerMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Pfizer [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_LeasesLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Leases [Line Items]</label>
    <label xml:lang="en-US" xlink:label="nktr_LeasesLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Leases [Line Items]</label>
    <label xml:lang="en-US" xlink:label="nktr_PercentageCeilingOnRentIncrease_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage ceiling on rent increases, annually, capital lease</label>
    <label xml:lang="en-US" xlink:label="nktr_PercentageCeilingOnRentIncrease_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Percentage Ceiling On Rent Increase</label>
    <label xml:lang="en-US" xlink:label="nktr_CapitalLeasesTerminationDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">San Carlos facility capital leases, termination date</label>
    <label xml:lang="en-US" xlink:label="nktr_CapitalLeasesTerminationDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Capital Leases Termination Date</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumSubleaseRentals" xlink:type="locator" xlink:label="us-gaap_CapitalLeasesFutureMinimumSubleaseRentals" />
    <label xml:lang="en-US" xlink:label="us-gaap_CapitalLeasesFutureMinimumSubleaseRentals_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Future minimum rental receipts under the San Carlos facility subleases</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CapitalLeasesFutureMinimumSubleaseRentals" xlink:to="us-gaap_CapitalLeasesFutureMinimumSubleaseRentals_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_CapitalLeasesFutureMinimumSubleaseRentals_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Capital Leases Future Minimum Sublease Rentals</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CapitalLeasedAssetsGross" xlink:type="locator" xlink:label="us-gaap_CapitalLeasedAssetsGross" />
    <label xml:lang="en-US" xlink:label="us-gaap_CapitalLeasedAssetsGross_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Book value of assets, gross</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CapitalLeasedAssetsGross" xlink:to="us-gaap_CapitalLeasedAssetsGross_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_CapitalLeasedAssetsGross_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Capital Leased Assets Gross</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CapitalLeasesBalanceSheetAssetsByMajorClassNet" xlink:type="locator" xlink:label="us-gaap_CapitalLeasesBalanceSheetAssetsByMajorClassNet" />
    <label xml:lang="en-US" xlink:label="us-gaap_CapitalLeasesBalanceSheetAssetsByMajorClassNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net book value of assets</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CapitalLeasesBalanceSheetAssetsByMajorClassNet" xlink:to="us-gaap_CapitalLeasesBalanceSheetAssetsByMajorClassNet_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_CapitalLeasesBalanceSheetAssetsByMajorClassNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Capital Leases Balance Sheet Assets By Major Class Net</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDueCurrent" xlink:type="locator" xlink:label="us-gaap_CapitalLeasesFutureMinimumPaymentsDueCurrent" />
    <label xml:lang="en-US" xlink:label="us-gaap_CapitalLeasesFutureMinimumPaymentsDueCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2016</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CapitalLeasesFutureMinimumPaymentsDueCurrent" xlink:to="us-gaap_CapitalLeasesFutureMinimumPaymentsDueCurrent_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_CapitalLeasesFutureMinimumPaymentsDueCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Capital Leases Future Minimum Payments Due Current</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears" xlink:type="locator" xlink:label="us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears" />
    <label xml:lang="en-US" xlink:label="us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2017</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears" xlink:to="us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Capital Leases Future Minimum Payments Due In Two Years</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDueInThreeYears" xlink:type="locator" xlink:label="us-gaap_CapitalLeasesFutureMinimumPaymentsDueInThreeYears" />
    <label xml:lang="en-US" xlink:label="us-gaap_CapitalLeasesFutureMinimumPaymentsDueInThreeYears_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2018</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CapitalLeasesFutureMinimumPaymentsDueInThreeYears" xlink:to="us-gaap_CapitalLeasesFutureMinimumPaymentsDueInThreeYears_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_CapitalLeasesFutureMinimumPaymentsDueInThreeYears_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Capital Leases Future Minimum Payments Due In Three Years</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDue" xlink:type="locator" xlink:label="us-gaap_CapitalLeasesFutureMinimumPaymentsDue" />
    <label xml:lang="en-US" xlink:label="us-gaap_CapitalLeasesFutureMinimumPaymentsDue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total minimum payments required</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CapitalLeasesFutureMinimumPaymentsDue" xlink:to="us-gaap_CapitalLeasesFutureMinimumPaymentsDue_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_CapitalLeasesFutureMinimumPaymentsDue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Capital Leases Future Minimum Payments Due</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsInterestIncludedInPayments" xlink:type="locator" xlink:label="us-gaap_CapitalLeasesFutureMinimumPaymentsInterestIncludedInPayments" />
    <label xml:lang="en-US" xlink:label="us-gaap_CapitalLeasesFutureMinimumPaymentsInterestIncludedInPayments_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Less: amount representing interest</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CapitalLeasesFutureMinimumPaymentsInterestIncludedInPayments" xlink:to="us-gaap_CapitalLeasesFutureMinimumPaymentsInterestIncludedInPayments_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_CapitalLeasesFutureMinimumPaymentsInterestIncludedInPayments_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Capital Leases Future Minimum Payments Interest Included In Payments</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsPresentValueOfNetMinimumPayments" xlink:type="locator" xlink:label="us-gaap_CapitalLeasesFutureMinimumPaymentsPresentValueOfNetMinimumPayments" />
    <label xml:lang="en-US" xlink:label="us-gaap_CapitalLeasesFutureMinimumPaymentsPresentValueOfNetMinimumPayments_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Present value of future minimum lease payments</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CapitalLeasesFutureMinimumPaymentsPresentValueOfNetMinimumPayments" xlink:to="us-gaap_CapitalLeasesFutureMinimumPaymentsPresentValueOfNetMinimumPayments_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_CapitalLeasesFutureMinimumPaymentsPresentValueOfNetMinimumPayments_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Capital Leases Future Minimum Payments Present Value Of Net Minimum Payments</label>
    <label xml:lang="en-US" xlink:label="us-gaap_CapitalLeaseObligationsCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Less: current portion</label>
    <label xml:lang="en-US" xlink:label="us-gaap_CapitalLeaseObligationsNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Capital lease obligation, less current portion</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_SubleaseTermCommencedStartDate" xlink:type="locator" xlink:label="nktr_SubleaseTermCommencedStartDate" />
    <label xml:lang="en-US" xlink:label="nktr_SubleaseTermCommencedStartDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Sublease term commenced start date.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_SubleaseTermCommencedStartDate" xlink:to="nktr_SubleaseTermCommencedStartDate_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_SubleaseTermCommencedPeriod" xlink:type="locator" xlink:label="nktr_SubleaseTermCommencedPeriod" />
    <label xml:lang="en-US" xlink:label="nktr_SubleaseTermCommencedPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Sublease term commenced Period.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_SubleaseTermCommencedPeriod" xlink:to="nktr_SubleaseTermCommencedPeriod_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_SubleaseTermCommencedEndDate" xlink:type="locator" xlink:label="nktr_SubleaseTermCommencedEndDate" />
    <label xml:lang="en-US" xlink:label="nktr_SubleaseTermCommencedEndDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Sublease term commenced end date.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_SubleaseTermCommencedEndDate" xlink:to="nktr_SubleaseTermCommencedEndDate_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_OperatingSublease" xlink:type="locator" xlink:label="nktr_OperatingSublease" />
    <label xml:lang="en-US" xlink:label="nktr_OperatingSublease_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Operating sublease.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_OperatingSublease" xlink:to="nktr_OperatingSublease_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_SubleaseTermCommencedStartDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating Sublease term commenced start date</label>
    <label xml:lang="en-US" xlink:label="nktr_SubleaseTermCommencedStartDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Sublease Term Commenced Start Date</label>
    <label xml:lang="en-US" xlink:label="nktr_SubleaseTermCommencedPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating Sublease term commenced period</label>
    <label xml:lang="en-US" xlink:label="nktr_SubleaseTermCommencedPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Sublease Term Commenced Period</label>
    <label xml:lang="en-US" xlink:label="nktr_SubleaseTermCommencedEndDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating Sublease term commenced end date</label>
    <label xml:lang="en-US" xlink:label="nktr_SubleaseTermCommencedEndDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Sublease Term Commenced End Date</label>
    <label xml:lang="en-US" xlink:label="nktr_OperatingSublease_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating sublease</label>
    <label xml:lang="en-US" xlink:label="nktr_OperatingSublease_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Operating Sublease</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent" xlink:type="locator" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent" />
    <label xml:lang="en-US" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2016</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Operating Leases Future Minimum Payments Due Current</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears" xlink:type="locator" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears" />
    <label xml:lang="en-US" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2017</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Operating Leases Future Minimum Payments Due In Two Years</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" xlink:type="locator" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" />
    <label xml:lang="en-US" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2018</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Operating Leases Future Minimum Payments Due In Three Years</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" xlink:type="locator" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" />
    <label xml:lang="en-US" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2019</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Operating Leases Future Minimum Payments Due In Four Years</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears" xlink:type="locator" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears" />
    <label xml:lang="en-US" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2020</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Operating Leases Future Minimum Payments Due In Five Years</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:type="locator" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDue" />
    <label xml:lang="en-US" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total future minimum lease payments</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDue_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Operating Leases Future Minimum Payments Due</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LeaseAndRentalExpense" xlink:type="locator" xlink:label="us-gaap_LeaseAndRentalExpense" />
    <label xml:lang="en-US" xlink:label="us-gaap_LeaseAndRentalExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Rent expense for operating leases</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LeaseAndRentalExpense" xlink:to="us-gaap_LeaseAndRentalExpense_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_LeaseAndRentalExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Lease And Rental Expense</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredRentCreditNoncurrent" xlink:type="locator" xlink:label="us-gaap_DeferredRentCreditNoncurrent" />
    <label xml:lang="en-US" xlink:label="us-gaap_DeferredRentCreditNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred rent</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredRentCreditNoncurrent" xlink:to="us-gaap_DeferredRentCreditNoncurrent_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_DeferredRentCreditNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Rent Credit Noncurrent</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_ProceedsFromSaleOfPotentialFutureRoyaltiesGross" xlink:type="locator" xlink:label="nktr_ProceedsFromSaleOfPotentialFutureRoyaltiesGross" />
    <label xml:lang="en-US" xlink:label="nktr_ProceedsFromSaleOfPotentialFutureRoyaltiesGross_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Proceeds from sale of potential future royalties gross.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_ProceedsFromSaleOfPotentialFutureRoyaltiesGross" xlink:to="nktr_ProceedsFromSaleOfPotentialFutureRoyaltiesGross_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_TransactionCostsRelatedToSaleOfPotentialFutureRoyalties" xlink:type="locator" xlink:label="nktr_TransactionCostsRelatedToSaleOfPotentialFutureRoyalties" />
    <label xml:lang="en-US" xlink:label="nktr_TransactionCostsRelatedToSaleOfPotentialFutureRoyalties_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Transaction costs related to sale of potential future royalties.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_TransactionCostsRelatedToSaleOfPotentialFutureRoyalties" xlink:to="nktr_TransactionCostsRelatedToSaleOfPotentialFutureRoyalties_lbl" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherLiabilitiesDisclosureAbstract" xlink:type="locator" xlink:label="us-gaap_OtherLiabilitiesDisclosureAbstract" />
    <label xml:lang="en-US" xlink:label="us-gaap_OtherLiabilitiesDisclosureAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Other Liabilities Disclosure [Abstract]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherLiabilitiesDisclosureAbstract" xlink:to="us-gaap_OtherLiabilitiesDisclosureAbstract_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_LiabilityRelatedToSaleOfFutureRoyaltiesLineItems" xlink:type="locator" xlink:label="nktr_LiabilityRelatedToSaleOfFutureRoyaltiesLineItems" />
    <label xml:lang="en-US" xlink:label="nktr_LiabilityRelatedToSaleOfFutureRoyaltiesLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Liability related to sale of future royalties.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_LiabilityRelatedToSaleOfFutureRoyaltiesLineItems" xlink:to="nktr_LiabilityRelatedToSaleOfFutureRoyaltiesLineItems_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_LiabilityRelatedToSaleOfFutureRoyaltiesTable" xlink:type="locator" xlink:label="nktr_LiabilityRelatedToSaleOfFutureRoyaltiesTable" />
    <label xml:lang="en-US" xlink:label="nktr_LiabilityRelatedToSaleOfFutureRoyaltiesTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Liability related to sale of future royalties.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_LiabilityRelatedToSaleOfFutureRoyaltiesTable" xlink:to="nktr_LiabilityRelatedToSaleOfFutureRoyaltiesTable_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_LiabilityRelatedToSaleOfFutureRoyaltiesTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Liability Related To Sale Of Future Royalties [Table]</label>
    <label xml:lang="en-US" xlink:label="nktr_LiabilityRelatedToSaleOfFutureRoyaltiesTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Liability Related To Sale Of Future Royalties [Table]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_TypeOfArrangementAxis" xlink:type="locator" xlink:label="us-gaap_TypeOfArrangementAxis" />
    <label xml:lang="en-US" xlink:label="us-gaap_TypeOfArrangementAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Type Of Arrangement</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TypeOfArrangementAxis" xlink:to="us-gaap_TypeOfArrangementAxis_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_TypeOfArrangementAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Type Of Arrangement [Axis]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:type="locator" xlink:label="us-gaap_ArrangementsAndNonarrangementTransactionsMember" />
    <label xml:lang="en-US" xlink:label="us-gaap_ArrangementsAndNonarrangementTransactionsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Arrangements And Nonarrangement Transactions Member</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:to="us-gaap_ArrangementsAndNonarrangementTransactionsMember_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_ArrangementsAndNonarrangementTransactionsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Arrangements And Nonarrangement Transactions [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_PurchaseAndSaleAgreementMember" xlink:type="locator" xlink:label="nktr_PurchaseAndSaleAgreementMember" />
    <label xml:lang="en-US" xlink:label="nktr_PurchaseAndSaleAgreementMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Purchase and sale agreement.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_PurchaseAndSaleAgreementMember" xlink:to="nktr_PurchaseAndSaleAgreementMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_PurchaseAndSaleAgreementMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Purchase and Sale Agreement with RPI [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_PurchaseAndSaleAgreementMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Purchase And Sale Agreement [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_LiabilityRelatedToSaleOfFutureRoyaltiesLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Liability Related to the Sale of Future Royalties [Line Items]</label>
    <label xml:lang="en-US" xlink:label="nktr_LiabilityRelatedToSaleOfFutureRoyaltiesLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Liability Related To Sale Of Future Royalties [Line Items]</label>
    <label xml:lang="en-US" xlink:label="nktr_ProceedsFromSaleOfPotentialFutureRoyaltiesGross_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Proceeds from sale of royalty rights</label>
    <label xml:lang="en-US" xlink:label="nktr_ProceedsFromSaleOfPotentialFutureRoyaltiesGross_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds From Sale Of Potential Future Royalties Gross</label>
    <label xml:lang="en-US" xlink:label="nktr_TransactionCostsRelatedToSaleOfPotentialFutureRoyalties_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Transaction costs related to sale of potential future royalties</label>
    <label xml:lang="en-US" xlink:label="nktr_TransactionCostsRelatedToSaleOfPotentialFutureRoyalties_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Transaction Costs Related To Sale Of Potential Future Royalties</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_ProceedsFromSaleOfPotentialFutureRoyalties" xlink:type="locator" xlink:label="nktr_ProceedsFromSaleOfPotentialFutureRoyalties" />
    <label xml:lang="en-US" xlink:label="nktr_ProceedsFromSaleOfPotentialFutureRoyalties_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Proceeds from sale of potential future royalties.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_ProceedsFromSaleOfPotentialFutureRoyalties" xlink:to="nktr_ProceedsFromSaleOfPotentialFutureRoyalties_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_PartialRepaymentOfRoyaltySaleProceeds" xlink:type="locator" xlink:label="nktr_PartialRepaymentOfRoyaltySaleProceeds" />
    <label xml:lang="en-US" xlink:label="nktr_PartialRepaymentOfRoyaltySaleProceeds_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Partial repayment of royalty sale proceeds.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_PartialRepaymentOfRoyaltySaleProceeds" xlink:to="nktr_PartialRepaymentOfRoyaltySaleProceeds_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_LiabilityRelatedToSaleOfPotentialFutureRoyaltiesNonCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Liability related to the sale of future royalties&#8212;beginning balance</label>
    <label xml:lang="en-US" xlink:label="nktr_ProceedsFromSaleOfPotentialFutureRoyalties_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Proceeds from sale of future royalties</label>
    <label xml:lang="en-US" xlink:label="nktr_ProceedsFromSaleOfPotentialFutureRoyalties_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds From Sale Of Potential Future Royalties</label>
    <label xml:lang="en-US" xlink:label="nktr_PartialRepaymentOfRoyaltySaleProceeds_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Payments from Nektar to RPI</label>
    <label xml:lang="en-US" xlink:label="nktr_PartialRepaymentOfRoyaltySaleProceeds_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Partial Repayment Of Royalty Sale Proceeds</label>
    <label xml:lang="en-US" xlink:label="nktr_NonCashRoyaltyRevenueRelatedToSaleOfFutureRoyalties_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Non-cash CIMZIA&#174; and MIRCERA&#174; royalty revenue</label>
    <label xml:lang="en-US" xlink:label="nktr_NonCashInterestExpenseRelatedToSaleOfRoyalties_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Non-cash interest expense recognized</label>
    <label xml:lang="en-US" xlink:label="nktr_LiabilityRelatedToSaleOfPotentialFutureRoyaltiesNonCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Liability related to the sale of future royalties &#8211; ending balance</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_PaymentMadeForMilestoneNotAchievedYearTwo" xlink:type="locator" xlink:label="nktr_PaymentMadeForMilestoneNotAchievedYearTwo" />
    <label xml:lang="en-US" xlink:label="nktr_PaymentMadeForMilestoneNotAchievedYearTwo_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Payment made for milestone not achieved year two.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_PaymentMadeForMilestoneNotAchievedYearTwo" xlink:to="nktr_PaymentMadeForMilestoneNotAchievedYearTwo_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_PaymentMadeForMilestoneNotAchievedYearOne" xlink:type="locator" xlink:label="nktr_PaymentMadeForMilestoneNotAchievedYearOne" />
    <label xml:lang="en-US" xlink:label="nktr_PaymentMadeForMilestoneNotAchievedYearOne_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Payment made for milestone not achieved year one.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_PaymentMadeForMilestoneNotAchievedYearOne" xlink:to="nktr_PaymentMadeForMilestoneNotAchievedYearOne_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_RoyaltyAgreementContingentPaymentDescription" xlink:type="locator" xlink:label="nktr_RoyaltyAgreementContingentPaymentDescription" />
    <label xml:lang="en-US" xlink:label="nktr_RoyaltyAgreementContingentPaymentDescription_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Royalty agreement contingent payment description.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_RoyaltyAgreementContingentPaymentDescription" xlink:to="nktr_RoyaltyAgreementContingentPaymentDescription_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_PaymentMadeForMilestoneNotAchievedYearTwo_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Payment made for milestone not achieved year two</label>
    <label xml:lang="en-US" xlink:label="nktr_PaymentMadeForMilestoneNotAchievedYearTwo_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Payment Made For Milestone Not Achieved Year Two</label>
    <label xml:lang="en-US" xlink:label="nktr_PaymentMadeForMilestoneNotAchievedYearOne_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Payment made for milestone not achieved year one</label>
    <label xml:lang="en-US" xlink:label="nktr_PaymentMadeForMilestoneNotAchievedYearOne_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Payment Made For Milestone Not Achieved Year One</label>
    <label xml:lang="en-US" xlink:label="nktr_RoyaltyAgreementContingentPaymentDescription_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Royalty agreement contingent payment description</label>
    <label xml:lang="en-US" xlink:label="nktr_RoyaltyAgreementContingentPaymentDescription_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Royalty Agreement Contingent Payment Description</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_EstimatedAnnualInterestRateOnRoyaltyLiability" xlink:type="locator" xlink:label="nktr_EstimatedAnnualInterestRateOnRoyaltyLiability" />
    <label xml:lang="en-US" xlink:label="nktr_EstimatedAnnualInterestRateOnRoyaltyLiability_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Estimated annual interest rate on royalty liability.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_EstimatedAnnualInterestRateOnRoyaltyLiability" xlink:to="nktr_EstimatedAnnualInterestRateOnRoyaltyLiability_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_EstimatedAnnualInterestRateOnRoyaltyLiability_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Annual interest rate</label>
    <label xml:lang="en-US" xlink:label="nktr_EstimatedAnnualInterestRateOnRoyaltyLiability_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Estimated Annual Interest Rate On Royalty Liability</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LossContingenciesTable" xlink:type="locator" xlink:label="us-gaap_LossContingenciesTable" />
    <label xml:lang="en-US" xlink:label="us-gaap_LossContingenciesTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loss Contingencies [Table]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LossContingenciesTable" xlink:to="us-gaap_LossContingenciesTable_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_LossContingenciesTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Loss Contingencies [Table]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LossContingenciesByNatureOfContingencyAxis" xlink:type="locator" xlink:label="us-gaap_LossContingenciesByNatureOfContingencyAxis" />
    <label xml:lang="en-US" xlink:label="us-gaap_LossContingenciesByNatureOfContingencyAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loss Contingencies By Nature Of Contingency</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LossContingenciesByNatureOfContingencyAxis" xlink:to="us-gaap_LossContingenciesByNatureOfContingencyAxis_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_LossContingenciesByNatureOfContingencyAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Loss Contingencies By Nature Of Contingency [Axis]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LossContingencyNatureDomain" xlink:type="locator" xlink:label="us-gaap_LossContingencyNatureDomain" />
    <label xml:lang="en-US" xlink:label="us-gaap_LossContingencyNatureDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loss Contingency Nature</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LossContingencyNatureDomain" xlink:to="us-gaap_LossContingencyNatureDomain_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_LossContingencyNatureDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Loss Contingency Nature [Domain]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IndemnificationGuaranteeMember" xlink:type="locator" xlink:label="us-gaap_IndemnificationGuaranteeMember" />
    <label xml:lang="en-US" xlink:label="us-gaap_IndemnificationGuaranteeMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Indemnification Obligation [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IndemnificationGuaranteeMember" xlink:to="us-gaap_IndemnificationGuaranteeMember_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_IndemnificationGuaranteeMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Indemnification Guarantee [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_MergerAndAcquisitionRelatedClaimsMember" xlink:type="locator" xlink:label="nktr_MergerAndAcquisitionRelatedClaimsMember" />
    <label xml:lang="en-US" xlink:label="nktr_MergerAndAcquisitionRelatedClaimsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Merger and acquisition related claims.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_MergerAndAcquisitionRelatedClaimsMember" xlink:to="nktr_MergerAndAcquisitionRelatedClaimsMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_MergerAndAcquisitionRelatedClaimsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Merger and Acquisition Related Claims [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_MergerAndAcquisitionRelatedClaimsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Merger And Acquisition Related Claims [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_SecuritiesRelatedClaimsMember" xlink:type="locator" xlink:label="nktr_SecuritiesRelatedClaimsMember" />
    <label xml:lang="en-US" xlink:label="nktr_SecuritiesRelatedClaimsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Securities related claims.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_SecuritiesRelatedClaimsMember" xlink:to="nktr_SecuritiesRelatedClaimsMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_SecuritiesRelatedClaimsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Securities Related Claims [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_SecuritiesRelatedClaimsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Securities Related Claims [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_NonSecuritiesRelatedClaimsMember" xlink:type="locator" xlink:label="nktr_NonSecuritiesRelatedClaimsMember" />
    <label xml:lang="en-US" xlink:label="nktr_NonSecuritiesRelatedClaimsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Non-securities related claims.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_NonSecuritiesRelatedClaimsMember" xlink:to="nktr_NonSecuritiesRelatedClaimsMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_NonSecuritiesRelatedClaimsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Non-Securities Related Claims [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_NonSecuritiesRelatedClaimsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Non Securities Related Claims [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LossContingenciesLineItems" xlink:type="locator" xlink:label="us-gaap_LossContingenciesLineItems" />
    <label xml:lang="en-US" xlink:label="us-gaap_LossContingenciesLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loss Contingencies [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LossContingenciesLineItems" xlink:to="us-gaap_LossContingenciesLineItems_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_LossContingenciesLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Loss Contingencies [Line Items]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DirectOperatingCostRoyaltyExpense" xlink:type="locator" xlink:label="us-gaap_DirectOperatingCostRoyaltyExpense" />
    <label xml:lang="en-US" xlink:label="us-gaap_DirectOperatingCostRoyaltyExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Royalty expense</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DirectOperatingCostRoyaltyExpense" xlink:to="us-gaap_DirectOperatingCostRoyaltyExpense_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_DirectOperatingCostRoyaltyExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Direct Operating Cost Royalty Expense</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PurchaseCommitmentRemainingMinimumAmountCommitted" xlink:type="locator" xlink:label="us-gaap_PurchaseCommitmentRemainingMinimumAmountCommitted" />
    <label xml:lang="en-US" xlink:label="us-gaap_PurchaseCommitmentRemainingMinimumAmountCommitted_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Purchase commitments related to contract manufacturing, clinical development and certain other items</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PurchaseCommitmentRemainingMinimumAmountCommitted" xlink:to="us-gaap_PurchaseCommitmentRemainingMinimumAmountCommitted_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_PurchaseCommitmentRemainingMinimumAmountCommitted_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Purchase Commitment Remaining Minimum Amount Committed</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_DamageClaimForUnpaidLicensingFee" xlink:type="locator" xlink:label="nktr_DamageClaimForUnpaidLicensingFee" />
    <label xml:lang="en-US" xlink:label="nktr_DamageClaimForUnpaidLicensingFee_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Damage Claim For Unpaid Licensing Fee</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_DamageClaimForUnpaidLicensingFee" xlink:to="nktr_DamageClaimForUnpaidLicensingFee_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_DamageClaimForUnpaidLicensingFee_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Damage claim for unpaid licensing fee</label>
    <label xml:lang="en-US" xlink:label="nktr_DamageClaimForUnpaidLicensingFee_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Damage Claim For Unpaid Licensing Fee</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_LossContingencyAccrualAtCarryingValue" xlink:type="locator" xlink:label="us-gaap_LossContingencyAccrualAtCarryingValue" />
    <label xml:lang="en-US" xlink:label="us-gaap_LossContingencyAccrualAtCarryingValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Indemnification obligations, liabilities</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LossContingencyAccrualAtCarryingValue" xlink:to="us-gaap_LossContingencyAccrualAtCarryingValue_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_LossContingencyAccrualAtCarryingValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Loss Contingency Accrual At Carrying Value</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_ObligationsUnderDirectorAndOfficerIndemnificationsPerIncident" xlink:type="locator" xlink:label="nktr_ObligationsUnderDirectorAndOfficerIndemnificationsPerIncident" />
    <label xml:lang="en-US" xlink:label="nktr_ObligationsUnderDirectorAndOfficerIndemnificationsPerIncident_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Obligations under director and officer indemnifications per incident.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_ObligationsUnderDirectorAndOfficerIndemnificationsPerIncident" xlink:to="nktr_ObligationsUnderDirectorAndOfficerIndemnificationsPerIncident_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_ObligationsUnderDirectorAndOfficerIndemnificationsPerIncident_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Obligations under Director and Officer Indemnifications per incident</label>
    <label xml:lang="en-US" xlink:label="nktr_ObligationsUnderDirectorAndOfficerIndemnificationsPerIncident_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Obligations Under Director And Officer Indemnifications Per Incident</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfStockByClassTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfStockByClassTable" />
    <label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfStockByClassTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Stock By Class [Table]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfStockByClassTable" xlink:to="us-gaap_ScheduleOfStockByClassTable_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfStockByClassTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Schedule Of Stock By Class [Table]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_TwoThousandTwelveEquityIncentivePlanMember" xlink:type="locator" xlink:label="nktr_TwoThousandTwelveEquityIncentivePlanMember" />
    <label xml:lang="en-US" xlink:label="nktr_TwoThousandTwelveEquityIncentivePlanMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Two Thousand Twelve Equity Incentive Plan [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_TwoThousandTwelveEquityIncentivePlanMember" xlink:to="nktr_TwoThousandTwelveEquityIncentivePlanMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_TwoThousandTwelveEquityIncentivePlanMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2012 Performance Incentive Plan [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_TwoThousandTwelveEquityIncentivePlanMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Two Thousand Twelve Equity Incentive Plan [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_TitleOfIndividualAxis" xlink:type="locator" xlink:label="us-gaap_TitleOfIndividualAxis" />
    <label xml:lang="en-US" xlink:label="us-gaap_TitleOfIndividualAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Title Of Individual</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TitleOfIndividualAxis" xlink:to="us-gaap_TitleOfIndividualAxis_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_TitleOfIndividualAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Title Of Individual [Axis]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_TitleOfIndividualWithRelationshipToEntityDomain" xlink:type="locator" xlink:label="us-gaap_TitleOfIndividualWithRelationshipToEntityDomain" />
    <label xml:lang="en-US" xlink:label="us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Title Of Individual With Relationship To Entity</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TitleOfIndividualWithRelationshipToEntityDomain" xlink:to="us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Title Of Individual With Relationship To Entity [Domain]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_EmployeeMember" xlink:type="locator" xlink:label="nktr_EmployeeMember" />
    <label xml:lang="en-US" xlink:label="nktr_EmployeeMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Employee [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_EmployeeMember" xlink:to="nktr_EmployeeMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_EmployeeMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Employee [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_EmployeeMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Employee [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DirectorMember" xlink:type="locator" xlink:label="us-gaap_DirectorMember" />
    <label xml:lang="en-US" xlink:label="us-gaap_DirectorMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Director [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DirectorMember" xlink:to="us-gaap_DirectorMember_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_DirectorMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Director [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_TwoThousandNonOfficerEquityIncentivePlanMember" xlink:type="locator" xlink:label="nktr_TwoThousandNonOfficerEquityIncentivePlanMember" />
    <label xml:lang="en-US" xlink:label="nktr_TwoThousandNonOfficerEquityIncentivePlanMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">2000 Non-Officer Equity Incentive Plan.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_TwoThousandNonOfficerEquityIncentivePlanMember" xlink:to="nktr_TwoThousandNonOfficerEquityIncentivePlanMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_TwoThousandNonOfficerEquityIncentivePlanMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2000 Non-Officer Equity Incentive Plan [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_TwoThousandNonOfficerEquityIncentivePlanMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Two Thousand Non Officer Equity Incentive Plan [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SubsidiarySaleOfStockAxis" xlink:type="locator" xlink:label="us-gaap_SubsidiarySaleOfStockAxis" />
    <label xml:lang="en-US" xlink:label="us-gaap_SubsidiarySaleOfStockAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Subsidiary Sale Of Stock</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="us-gaap_SubsidiarySaleOfStockAxis_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_SubsidiarySaleOfStockAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Subsidiary Sale Of Stock [Axis]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain" xlink:type="locator" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain" />
    <label xml:lang="en-US" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Sale Of Stock Name Of Transaction</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SaleOfStockNameOfTransactionDomain" xlink:to="us-gaap_SaleOfStockNameOfTransactionDomain_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Sale Of Stock Name Of Transaction [Domain]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EmployeeStockMember" xlink:type="locator" xlink:label="us-gaap_EmployeeStockMember" />
    <label xml:lang="en-US" xlink:label="us-gaap_EmployeeStockMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Employee Stock Purchase Plan [Member]</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_EmployeeStockMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Employee Stock [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ClassOfStockLineItems" xlink:type="locator" xlink:label="us-gaap_ClassOfStockLineItems" />
    <label xml:lang="en-US" xlink:label="us-gaap_ClassOfStockLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Class of Stock [Line Items]</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_ClassOfStockLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Class Of Stock [Line Items]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_UnderwritersCommissionsAndDiscount" xlink:type="locator" xlink:label="nktr_UnderwritersCommissionsAndDiscount" />
    <label xml:lang="en-US" xlink:label="nktr_UnderwritersCommissionsAndDiscount_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Underwriters Commissions And Discount</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_StockIssuedDuringPeriodSharesNewIssues_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Sale of common stock, Shares</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:type="locator" xlink:label="us-gaap_ProceedsFromIssuanceOfCommonStock" />
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    <label xml:lang="en-US" xlink:label="nktr_UnderwritersCommissionsAndDiscount_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Underwriters Commissions And Discount</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PaymentsOfStockIssuanceCosts" xlink:type="locator" xlink:label="us-gaap_PaymentsOfStockIssuanceCosts" />
    <label xml:lang="en-US" xlink:label="us-gaap_PaymentsOfStockIssuanceCosts_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Legal, accounting fees, filing fees and other offering expenses</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsOfStockIssuanceCosts" xlink:to="us-gaap_PaymentsOfStockIssuanceCosts_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_PaymentsOfStockIssuanceCosts_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Payments Of Stock Issuance Costs</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" xlink:type="locator" xlink:label="us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" />
    <label xml:lang="en-US" xlink:label="us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, shares reserved for issuance in equity compensation plans</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" xlink:to="us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock Capital Shares Reserved For Future Issuance</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAndRestrictedStockUnitsOutstanding" xlink:type="locator" xlink:label="nktr_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAndRestrictedStockUnitsOutstanding" />
    <label xml:lang="en-US" xlink:label="nktr_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAndRestrictedStockUnitsOutstanding_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Share based compensation arrangement by share based payment award options and restricted stock units outstanding.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAndRestrictedStockUnitsOutstanding" xlink:to="nktr_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAndRestrictedStockUnitsOutstanding_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_NumberOfSecuritiesAvailableForIssuanceUnderEquityCompensationPlans" xlink:type="locator" xlink:label="nktr_NumberOfSecuritiesAvailableForIssuanceUnderEquityCompensationPlans" />
    <label xml:lang="en-US" xlink:label="nktr_NumberOfSecuritiesAvailableForIssuanceUnderEquityCompensationPlans_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Number of securities remaining available for issuance under equity compensation plans.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_NumberOfSecuritiesAvailableForIssuanceUnderEquityCompensationPlans" xlink:to="nktr_NumberOfSecuritiesAvailableForIssuanceUnderEquityCompensationPlans_lbl" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_EquityCompensationPlansApprovedByShareholdersMember" xlink:type="locator" xlink:label="nktr_EquityCompensationPlansApprovedByShareholdersMember" />
    <label xml:lang="en-US" xlink:label="nktr_EquityCompensationPlansApprovedByShareholdersMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Equity compensation plans approved by security holders.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_EquityCompensationPlansApprovedByShareholdersMember" xlink:to="nktr_EquityCompensationPlansApprovedByShareholdersMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_EquityCompensationPlansApprovedByShareholdersMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Equity Compensation Plans Approved by Security Holders [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_EquityCompensationPlansApprovedByShareholdersMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Equity Compensation Plans Approved By Shareholders [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_EquityCompensationPlansUnapprovedBySecurityHoldersMember" xlink:type="locator" xlink:label="nktr_EquityCompensationPlansUnapprovedBySecurityHoldersMember" />
    <label xml:lang="en-US" xlink:label="nktr_EquityCompensationPlansUnapprovedBySecurityHoldersMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Equity compensation plans approved by security holders.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_EquityCompensationPlansUnapprovedBySecurityHoldersMember" xlink:to="nktr_EquityCompensationPlansUnapprovedBySecurityHoldersMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_EquityCompensationPlansUnapprovedBySecurityHoldersMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Equity Compensation Plans Not Approved by Security Holders [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_EquityCompensationPlansUnapprovedBySecurityHoldersMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Equity Compensation Plans Unapproved By Security Holders [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share-based Compensation Arrangement by Share-based Payment Award [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Share Based Compensation Arrangement By Share Based Payment Award [Line Items]</label>
    <label xml:lang="en-US" xlink:label="nktr_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAndRestrictedStockUnitsOutstanding_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of Securities to be Issued Upon Exercise of Outstanding Options &amp; Vesting of RSUs</label>
    <label xml:lang="en-US" xlink:label="nktr_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAndRestrictedStockUnitsOutstanding_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Share Based Compensation Arrangement By Share Based Payment Award Options And Restricted Stock Units Outstanding</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1" xlink:type="locator" xlink:label="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1" />
    <label xml:lang="en-US" xlink:label="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted-Average Exercise Price of Outstanding Options</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1" xlink:to="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Sharebased Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Exercisable Options Weighted Average Exercise Price1</label>
    <label xml:lang="en-US" xlink:label="nktr_NumberOfSecuritiesAvailableForIssuanceUnderEquityCompensationPlans_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of Securities Remaining Available for Issuance Under Equity Compensation Plans (Excluding Securities Reflected in Column)</label>
    <label xml:lang="en-US" xlink:label="nktr_NumberOfSecuritiesAvailableForIssuanceUnderEquityCompensationPlans_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Number Of Securities Available For Issuance Under Equity Compensation Plans</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized" />
    <label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Additional new shares available for award grants</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Share Based Compensation Arrangement By Share Based Payment Award Number Of Additional Shares Authorized</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1" />
    <label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Service period for stock-based compensation award granted</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Share Based Compensation Arrangement By Share Based Payment Award Award Requisite Service Period1</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" />
    <label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Awards granted</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_ShareBasedCompensationPlansShareLimitForEveryOneShare" xlink:type="locator" xlink:label="nktr_ShareBasedCompensationPlansShareLimitForEveryOneShare" />
    <label xml:lang="en-US" xlink:label="nktr_ShareBasedCompensationPlansShareLimitForEveryOneShare_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Share based compensation plan&apos;s share limit for every one share.</label>
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" />
    <label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of common stock shares available for stock options grants</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant</label>
    <label xml:lang="en-US" xlink:label="nktr_ShareBasedCompensationPlansShareLimitForEveryOneShare_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share-based compensation plan&apos;s share limit reduction for every one restricted stock unit granted</label>
    <label xml:lang="en-US" xlink:label="nktr_ShareBasedCompensationPlansShareLimitForEveryOneShare_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Share Based Compensation Plans Share Limit For Every One Share</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:type="locator" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" />
    <label xml:lang="en-US" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock options term under equity incentive plans</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Sharebased Compensation Arrangement By Sharebased Payment Award Expiration Period</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_PercentageOfPurchasePriceOfStock" xlink:type="locator" xlink:label="nktr_PercentageOfPurchasePriceOfStock" />
    <label xml:lang="en-US" xlink:label="nktr_PercentageOfPurchasePriceOfStock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Percentage of purchase price of stock.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_PercentageOfPurchasePriceOfStock" xlink:to="nktr_PercentageOfPurchasePriceOfStock_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_PercentageOfPurchasePriceOfStock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage of purchase price of stock</label>
    <label xml:lang="en-US" xlink:label="nktr_PercentageOfPurchasePriceOfStock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Percentage Of Purchase Price Of Stock</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent" xlink:type="locator" xlink:label="us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent" />
    <label xml:lang="en-US" xlink:label="us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maximum 401(k) per employee, percentage of annual salary</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Defined Contribution Plan Maximum Annual Contributions Per Employee Percent</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredCompensationArrangementWithIndividualEmployerContribution" xlink:type="locator" xlink:label="us-gaap_DeferredCompensationArrangementWithIndividualEmployerContribution" />
    <label xml:lang="en-US" xlink:label="us-gaap_DeferredCompensationArrangementWithIndividualEmployerContribution_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Matching 401(k) employer contribution, maximum amount</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredCompensationArrangementWithIndividualEmployerContribution" xlink:to="us-gaap_DeferredCompensationArrangementWithIndividualEmployerContribution_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_DeferredCompensationArrangementWithIndividualEmployerContribution_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Compensation Arrangement With Individual Employer Contribution</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DefinedContributionPlanCostRecognized" xlink:type="locator" xlink:label="us-gaap_DefinedContributionPlanCostRecognized" />
    <label xml:lang="en-US" xlink:label="us-gaap_DefinedContributionPlanCostRecognized_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Compensation expense in connection with 401(k) retirement plan</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DefinedContributionPlanCostRecognized" xlink:to="us-gaap_DefinedContributionPlanCostRecognized_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_DefinedContributionPlanCostRecognized_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Defined Contribution Plan Cost Recognized</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_SeverancePaymentPeriodForExecutives" xlink:type="locator" xlink:label="nktr_SeverancePaymentPeriodForExecutives" />
    <label xml:lang="en-US" xlink:label="nktr_SeverancePaymentPeriodForExecutives_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Severance payment period for executives.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_SeverancePaymentPeriodForExecutives" xlink:to="nktr_SeverancePaymentPeriodForExecutives_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_SeverancePaymentPeriodForEmployees" xlink:type="locator" xlink:label="nktr_SeverancePaymentPeriodForEmployees" />
    <label xml:lang="en-US" xlink:label="nktr_SeverancePaymentPeriodForEmployees_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Severance payment period for employees.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_SeverancePaymentPeriodForEmployees" xlink:to="nktr_SeverancePaymentPeriodForEmployees_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_CashSeverancePaymentForToChiefExecutiveOfficer" xlink:type="locator" xlink:label="nktr_CashSeverancePaymentForToChiefExecutiveOfficer" />
    <label xml:lang="en-US" xlink:label="nktr_CashSeverancePaymentForToChiefExecutiveOfficer_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Cash Severance Payment For To Chief Executive Officer</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_CashSeverancePaymentForToChiefExecutiveOfficer" xlink:to="nktr_CashSeverancePaymentForToChiefExecutiveOfficer_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_SeverancePaymentPeriodForExecutives_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Severance payment period for executives</label>
    <label xml:lang="en-US" xlink:label="nktr_SeverancePaymentPeriodForExecutives_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Severance Payment Period For Executives</label>
    <label xml:lang="en-US" xlink:label="nktr_SeverancePaymentPeriodForEmployees_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Severance payment period for employees</label>
    <label xml:lang="en-US" xlink:label="nktr_SeverancePaymentPeriodForEmployees_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Severance Payment Period For Employees</label>
    <label xml:lang="en-US" xlink:label="nktr_CashSeverancePaymentForToChiefExecutiveOfficer_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash severance payment for chief executive officer</label>
    <label xml:lang="en-US" xlink:label="nktr_CashSeverancePaymentForToChiefExecutiveOfficer_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Cash Severance Payment For To Chief Executive Officer</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_LicenseAndCollaborationAgreementsLineItems" xlink:type="locator" xlink:label="nktr_LicenseAndCollaborationAgreementsLineItems" />
    <label xml:lang="en-US" xlink:label="nktr_LicenseAndCollaborationAgreementsLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">License and collaboration agreements.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_LicenseAndCollaborationAgreementsLineItems" xlink:to="nktr_LicenseAndCollaborationAgreementsLineItems_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_LicenseAndCollaborationAgreementsTable" xlink:type="locator" xlink:label="nktr_LicenseAndCollaborationAgreementsTable" />
    <label xml:lang="en-US" xlink:label="nktr_LicenseAndCollaborationAgreementsTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">License and collaboration agreements.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_LicenseAndCollaborationAgreementsTable" xlink:to="nktr_LicenseAndCollaborationAgreementsTable_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_LicenseAndCollaborationAgreementsTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">License And Collaboration Agreements [Table]</label>
    <label xml:lang="en-US" xlink:label="nktr_LicenseAndCollaborationAgreementsTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">License And Collaboration Agreements [Table]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_AstraZenecaAbMember" xlink:type="locator" xlink:label="nktr_AstraZenecaAbMember" />
    <label xml:lang="en-US" xlink:label="nktr_AstraZenecaAbMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">AstraZeneca AB.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_AstraZenecaAbMember" xlink:to="nktr_AstraZenecaAbMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_AstraZenecaAbMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">AstraZeneca AB [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_AstraZenecaAbMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Astra Zeneca Ab [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_RocheMember" xlink:type="locator" xlink:label="nktr_RocheMember" />
    <label xml:lang="en-US" xlink:label="nktr_RocheMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Roche.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_RocheMember" xlink:to="nktr_RocheMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_RocheMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Roche [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_RocheMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Roche [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_BaxaltaIncorporatedMember" xlink:type="locator" xlink:label="nktr_BaxaltaIncorporatedMember" />
    <label xml:lang="en-US" xlink:label="nktr_BaxaltaIncorporatedMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Baxalta Incorporated [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_BaxaltaIncorporatedMember" xlink:to="nktr_BaxaltaIncorporatedMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_BaxaltaIncorporatedMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Baxalta Incorporated [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_BaxaltaIncorporatedMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Baxalta Incorporated [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_AmgenIncMember" xlink:type="locator" xlink:label="nktr_AmgenIncMember" />
    <label xml:lang="en-US" xlink:label="nktr_AmgenIncMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Amgen Inc.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_AmgenIncMember" xlink:to="nktr_AmgenIncMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_AmgenIncMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Amgen, Inc. [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_AmgenIncMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Amgen Inc [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_BayerHealthcareLLCMember" xlink:type="locator" xlink:label="nktr_BayerHealthcareLLCMember" />
    <label xml:lang="en-US" xlink:label="nktr_BayerHealthcareLLCMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Bayer Healthcare LLC.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_BayerHealthcareLLCMember" xlink:to="nktr_BayerHealthcareLLCMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_BayerHealthcareLLCMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Bayer Healthcare LLC [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_BayerHealthcareLLCMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Bayer Healthcare L L C [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_AffymaxIncMember" xlink:type="locator" xlink:label="nktr_AffymaxIncMember" />
    <label xml:lang="en-US" xlink:label="nktr_AffymaxIncMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Affymax Inc.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_AffymaxIncMember" xlink:to="nktr_AffymaxIncMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_AffymaxIncMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Affymax, Inc. [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_AffymaxIncMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Affymax Inc [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_OtherPartnerMember" xlink:type="locator" xlink:label="nktr_OtherPartnerMember" />
    <label xml:lang="en-US" xlink:label="nktr_OtherPartnerMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Other.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_OtherPartnerMember" xlink:to="nktr_OtherPartnerMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_OtherPartnerMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_OtherPartnerMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Other Partner [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_MOVANTIKAndMOVANTIKFixedDoseCombinationProgramMember" xlink:type="locator" xlink:label="nktr_MOVANTIKAndMOVANTIKFixedDoseCombinationProgramMember" />
    <label xml:lang="en-US" xlink:label="nktr_MOVANTIKAndMOVANTIKFixedDoseCombinationProgramMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">MOVANTIK And MOVANTIK fixed dose combination program. And MOVANTIK Fixed Dose Combination Program.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_MOVANTIKAndMOVANTIKFixedDoseCombinationProgramMember" xlink:to="nktr_MOVANTIKAndMOVANTIKFixedDoseCombinationProgramMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_MOVANTIKAndMOVANTIKFixedDoseCombinationProgramMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">MOVANTIKTM (NKTR-118) and MOVANTIKTM fixed-dose combination program (NKTR-119) [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_MOVANTIKAndMOVANTIKFixedDoseCombinationProgramMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">M O V A N T I K And M O V A N T I K Fixed Dose Combination Program [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_PEGASYSAndMIRCERAMember" xlink:type="locator" xlink:label="nktr_PEGASYSAndMIRCERAMember" />
    <label xml:lang="en-US" xlink:label="nktr_PEGASYSAndMIRCERAMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">PEGASYS And MIRCERA.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_PEGASYSAndMIRCERAMember" xlink:to="nktr_PEGASYSAndMIRCERAMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_PEGASYSAndMIRCERAMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">PEGASYS and MIRCERA [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_PEGASYSAndMIRCERAMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">P E G A S Y S And M I R C E R A [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_ADYNOVATEMember" xlink:type="locator" xlink:label="nktr_ADYNOVATEMember" />
    <label xml:lang="en-US" xlink:label="nktr_ADYNOVATEMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">ADYNOVATE.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_ADYNOVATEMember" xlink:to="nktr_ADYNOVATEMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_ADYNOVATEMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">ADYNOVATETM [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_ADYNOVATEMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">A D Y N O V A T E [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_NeulastaMember" xlink:type="locator" xlink:label="nktr_NeulastaMember" />
    <label xml:lang="en-US" xlink:label="nktr_NeulastaMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Neulasta.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_NeulastaMember" xlink:to="nktr_NeulastaMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_NeulastaMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Neulasta [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_NeulastaMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Neulasta [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_BayFourOneSixFiveFiveOneAmikacinInhaleMember" xlink:type="locator" xlink:label="nktr_BayFourOneSixFiveFiveOneAmikacinInhaleMember" />
    <label xml:lang="en-US" xlink:label="nktr_BayFourOneSixFiveFiveOneAmikacinInhaleMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">BAY41-6551 (Amikacin Inhale).</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_BayFourOneSixFiveFiveOneAmikacinInhaleMember" xlink:to="nktr_BayFourOneSixFiveFiveOneAmikacinInhaleMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_BayFourOneSixFiveFiveOneAmikacinInhaleMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">BAY41-6551 (Amikacin Inhale) [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_BayFourOneSixFiveFiveOneAmikacinInhaleMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Bay Four One Six Five Five One Amikacin Inhale [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_OMONTYSMember" xlink:type="locator" xlink:label="nktr_OMONTYSMember" />
    <label xml:lang="en-US" xlink:label="nktr_OMONTYSMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">OMONTYS.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_OMONTYSMember" xlink:to="nktr_OMONTYSMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_OMONTYSMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">OMONTYS [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_OMONTYSMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">O M O N T Y S [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_LicenseAndCollaborationAgreementsLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">License And Collaboration Agreements [Line Items]</label>
    <label xml:lang="en-US" xlink:label="nktr_LicenseAndCollaborationAgreementsLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">License And Collaboration Agreements [Line Items]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_PotentialDevelopmentMilestones" xlink:type="locator" xlink:label="nktr_PotentialDevelopmentMilestones" />
    <label xml:lang="en-US" xlink:label="nktr_PotentialDevelopmentMilestones_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Potential development milestones.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_PotentialDevelopmentMilestones" xlink:to="nktr_PotentialDevelopmentMilestones_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_LicenseAndCollaborationAgreementsAbstract" xlink:type="locator" xlink:label="nktr_LicenseAndCollaborationAgreementsAbstract" />
    <label xml:lang="en-US" xlink:label="nktr_LicenseAndCollaborationAgreementsAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">License and collaboration agreements.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_LicenseAndCollaborationAgreementsAbstract" xlink:to="nktr_LicenseAndCollaborationAgreementsAbstract_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_LicenseAndCollaborationAgreementsAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">License And Collaboration Agreements [Abstract]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredRevenueArrangementByTypeTable" xlink:type="locator" xlink:label="us-gaap_DeferredRevenueArrangementByTypeTable" />
    <label xml:lang="en-US" xlink:label="us-gaap_DeferredRevenueArrangementByTypeTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred Revenue Arrangement By Type [Table]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredRevenueArrangementByTypeTable" xlink:to="us-gaap_DeferredRevenueArrangementByTypeTable_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_DeferredRevenueArrangementByTypeTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Revenue Arrangement By Type [Table]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_MOVANTIKFixedDoseCombinationProgramMember" xlink:type="locator" xlink:label="nktr_MOVANTIKFixedDoseCombinationProgramMember" />
    <label xml:lang="en-US" xlink:label="nktr_MOVANTIKFixedDoseCombinationProgramMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">MOVANTIK Fixed Dose Combination Program.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_MOVANTIKFixedDoseCombinationProgramMember" xlink:to="nktr_MOVANTIKFixedDoseCombinationProgramMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_MOVANTIKFixedDoseCombinationProgramMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Movantik Fixed-dose Combination Program [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_MOVANTIKFixedDoseCombinationProgramMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">M O V A N T I K Fixed Dose Combination Program [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredRevenueArrangementTypeAxis" xlink:type="locator" xlink:label="us-gaap_DeferredRevenueArrangementTypeAxis" />
    <label xml:lang="en-US" xlink:label="us-gaap_DeferredRevenueArrangementTypeAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred Revenue Arrangement Type</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredRevenueArrangementTypeAxis" xlink:to="us-gaap_DeferredRevenueArrangementTypeAxis_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_DeferredRevenueArrangementTypeAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Revenue Arrangement Type [Axis]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredRevenueArrangementTypeDomain" xlink:type="locator" xlink:label="us-gaap_DeferredRevenueArrangementTypeDomain" />
    <label xml:lang="en-US" xlink:label="us-gaap_DeferredRevenueArrangementTypeDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred Revenue Arrangement Type</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredRevenueArrangementTypeDomain" xlink:to="us-gaap_DeferredRevenueArrangementTypeDomain_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_DeferredRevenueArrangementTypeDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Revenue Arrangement Type [Domain]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_UpFrontPaymentArrangementMember" xlink:type="locator" xlink:label="us-gaap_UpFrontPaymentArrangementMember" />
    <label xml:lang="en-US" xlink:label="us-gaap_UpFrontPaymentArrangementMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Upfront Payment Arrangement in 2007 [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_UpFrontPaymentArrangementMember" xlink:to="us-gaap_UpFrontPaymentArrangementMember_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_UpFrontPaymentArrangementMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Up Front Payment Arrangement [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_MOVANTIKMember" xlink:type="locator" xlink:label="nktr_MOVANTIKMember" />
    <label xml:lang="en-US" xlink:label="nktr_MOVANTIKMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">MOVANTIK.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_MOVANTIKMember" xlink:to="nktr_MOVANTIKMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_MOVANTIKMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">MOVANTIK [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_MOVANTIKMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">M O V A N T I K [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <label xml:lang="en-US" xlink:label="us-gaap_StatementScenarioAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Statement Scenario</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_StatementScenarioAxis_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_StatementScenarioAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Statement Scenario [Axis]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <label xml:lang="en-US" xlink:label="us-gaap_ScenarioUnspecifiedDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Scenario Unspecified</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_ScenarioUnspecifiedDomain_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_ScenarioUnspecifiedDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Scenario Unspecified [Domain]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScenarioForecastMember" xlink:type="locator" xlink:label="us-gaap_ScenarioForecastMember" />
    <label xml:lang="en-US" xlink:label="us-gaap_ScenarioForecastMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Scenario, Forecast [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScenarioForecastMember" xlink:to="us-gaap_ScenarioForecastMember_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_ScenarioForecastMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Scenario Forecast [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StatementGeographicalAxis" xlink:type="locator" xlink:label="us-gaap_StatementGeographicalAxis" />
    <label xml:lang="en-US" xlink:label="us-gaap_StatementGeographicalAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Statement Geographical</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementGeographicalAxis" xlink:to="us-gaap_StatementGeographicalAxis_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_StatementGeographicalAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Statement Geographical [Axis]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:type="locator" xlink:label="us-gaap_SegmentGeographicalDomain" />
    <label xml:lang="en-US" xlink:label="us-gaap_SegmentGeographicalDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Segment Geographical</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SegmentGeographicalDomain" xlink:to="us-gaap_SegmentGeographicalDomain_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_SegmentGeographicalDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Segment Geographical [Domain]</label>
    <loc xlink:href="http://xbrl.sec.gov/country/2013/country-2013-01-31.xsd#country_US" xlink:type="locator" xlink:label="country_US" />
    <label xml:lang="en-US" xlink:label="country_US_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">United States [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="country_US" xlink:to="country_US_lbl" />
    <label xml:lang="en-US" xlink:label="country_US_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">U S</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EuropeanUnionMember" xlink:type="locator" xlink:label="us-gaap_EuropeanUnionMember" />
    <label xml:lang="en-US" xlink:label="us-gaap_EuropeanUnionMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">European Union [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EuropeanUnionMember" xlink:to="us-gaap_EuropeanUnionMember_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_EuropeanUnionMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">European Union [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:type="locator" xlink:label="us-gaap_BalanceSheetLocationAxis" />
    <label xml:lang="en-US" xlink:label="us-gaap_BalanceSheetLocationAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Balance Sheet Location</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BalanceSheetLocationAxis" xlink:to="us-gaap_BalanceSheetLocationAxis_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_BalanceSheetLocationAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Balance Sheet Location [Axis]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:type="locator" xlink:label="us-gaap_BalanceSheetLocationDomain" />
    <label xml:lang="en-US" xlink:label="us-gaap_BalanceSheetLocationDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Balance Sheet Location</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BalanceSheetLocationDomain" xlink:to="us-gaap_BalanceSheetLocationDomain_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_BalanceSheetLocationDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Balance Sheet Location [Domain]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_OtherCurrentLiabilitiesMember" xlink:type="locator" xlink:label="us-gaap_OtherCurrentLiabilitiesMember" />
    <label xml:lang="en-US" xlink:label="us-gaap_OtherCurrentLiabilitiesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other Current Liabilities [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherCurrentLiabilitiesMember" xlink:to="us-gaap_OtherCurrentLiabilitiesMember_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_OtherCurrentLiabilitiesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Other Current Liabilities [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_HemophiliaMember" xlink:type="locator" xlink:label="nktr_HemophiliaMember" />
    <label xml:lang="en-US" xlink:label="nktr_HemophiliaMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Hemophilia.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_HemophiliaMember" xlink:to="nktr_HemophiliaMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_HemophiliaMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">ADYNOVATETM (Hemophilia) [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_HemophiliaMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Hemophilia [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_PegasysMember" xlink:type="locator" xlink:label="nktr_PegasysMember" />
    <label xml:lang="en-US" xlink:label="nktr_PegasysMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Pegasys.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_PegasysMember" xlink:to="nktr_PegasysMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_PegasysMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">PEGASYS [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_PegasysMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Pegasys [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_LicenseOptionMember" xlink:type="locator" xlink:label="nktr_LicenseOptionMember" />
    <label xml:lang="en-US" xlink:label="nktr_LicenseOptionMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">License Option.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_LicenseOptionMember" xlink:to="nktr_LicenseOptionMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_LicenseOptionMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">License Extension Option [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_LicenseOptionMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">License Option [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_MIRCERAMember" xlink:type="locator" xlink:label="nktr_MIRCERAMember" />
    <label xml:lang="en-US" xlink:label="nktr_MIRCERAMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">MIRCERA.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_MIRCERAMember" xlink:to="nktr_MIRCERAMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_MIRCERAMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">MIRCERA [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_MIRCERAMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">M I R C E R A [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_PrincipleTransactionRevenueDescriptionOfReportingCategoryAxis" xlink:type="locator" xlink:label="us-gaap_PrincipleTransactionRevenueDescriptionOfReportingCategoryAxis" />
    <label xml:lang="en-US" xlink:label="us-gaap_PrincipleTransactionRevenueDescriptionOfReportingCategoryAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Principle Transaction Revenue Description Of Reporting Category</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PrincipleTransactionRevenueDescriptionOfReportingCategoryAxis" xlink:to="us-gaap_PrincipleTransactionRevenueDescriptionOfReportingCategoryAxis_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_PrincipleTransactionRevenueDescriptionOfReportingCategoryAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Principle Transaction Revenue Description Of Reporting Category [Axis]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NameOfReportingCategoryDomain" xlink:type="locator" xlink:label="us-gaap_NameOfReportingCategoryDomain" />
    <label xml:lang="en-US" xlink:label="us-gaap_NameOfReportingCategoryDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Name Of Reporting Category</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NameOfReportingCategoryDomain" xlink:to="us-gaap_NameOfReportingCategoryDomain_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_NameOfReportingCategoryDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Name Of Reporting Category [Domain]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_PerformanceMilestonePaymentsMember" xlink:type="locator" xlink:label="nktr_PerformanceMilestonePaymentsMember" />
    <label xml:lang="en-US" xlink:label="nktr_PerformanceMilestonePaymentsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Performance Milestone Payments.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_PerformanceMilestonePaymentsMember" xlink:to="nktr_PerformanceMilestonePaymentsMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_PerformanceMilestonePaymentsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Performance-based Milestone Payments [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_PerformanceMilestonePaymentsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Performance Milestone Payments [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_OphthotechCorporationMember" xlink:type="locator" xlink:label="nktr_OphthotechCorporationMember" />
    <label xml:lang="en-US" xlink:label="nktr_OphthotechCorporationMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Ophthotech Corporation.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_OphthotechCorporationMember" xlink:to="nktr_OphthotechCorporationMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_OphthotechCorporationMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Ophthotech Corporation [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_OphthotechCorporationMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Ophthotech Corporation [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_FovistaMember" xlink:type="locator" xlink:label="nktr_FovistaMember" />
    <label xml:lang="en-US" xlink:label="nktr_FovistaMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Fovista.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_FovistaMember" xlink:to="nktr_FovistaMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_FovistaMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fovista [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_FovistaMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Fovista [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredRevenueArrangementLineItems" xlink:type="locator" xlink:label="us-gaap_DeferredRevenueArrangementLineItems" />
    <label xml:lang="en-US" xlink:label="us-gaap_DeferredRevenueArrangementLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred Revenue Arrangement [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredRevenueArrangementLineItems" xlink:to="us-gaap_DeferredRevenueArrangementLineItems_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_DeferredRevenueArrangementLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Revenue Arrangement [Line Items]</label>
    <label xml:lang="en-US" xlink:label="nktr_PotentialDevelopmentMilestones_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Potential future additional payments for development milestones</label>
    <label xml:lang="en-US" xlink:label="nktr_PotentialDevelopmentMilestones_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Potential Development Milestones</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_UpfrontAndMilestonePaymentsReceivedUnderLicenseAgreement" xlink:type="locator" xlink:label="nktr_UpfrontAndMilestonePaymentsReceivedUnderLicenseAgreement" />
    <label xml:lang="en-US" xlink:label="nktr_UpfrontAndMilestonePaymentsReceivedUnderLicenseAgreement_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Upfront and milestone payments received under license agreement.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_UpfrontAndMilestonePaymentsReceivedUnderLicenseAgreement" xlink:to="nktr_UpfrontAndMilestonePaymentsReceivedUnderLicenseAgreement_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_ContingentPaymentsReceivableBasedOnDevelopmentEvents" xlink:type="locator" xlink:label="nktr_ContingentPaymentsReceivableBasedOnDevelopmentEvents" />
    <label xml:lang="en-US" xlink:label="nktr_ContingentPaymentsReceivableBasedOnDevelopmentEvents_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Contingent payments receivable based on development events.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_ContingentPaymentsReceivableBasedOnDevelopmentEvents" xlink:to="nktr_ContingentPaymentsReceivableBasedOnDevelopmentEvents_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_UpfrontAndMilestonePaymentsReceivedUnderLicenseAgreement_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Received upfront and milestone payments</label>
    <label xml:lang="en-US" xlink:label="nktr_UpfrontAndMilestonePaymentsReceivedUnderLicenseAgreement_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Upfront And Milestone Payments Received Under License Agreement</label>
    <label xml:lang="en-US" xlink:label="nktr_ContingentPaymentsReceivableBasedOnDevelopmentEvents_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Contingent payments receivable based on development events regulatory to be pursued and completed solely by others</label>
    <label xml:lang="en-US" xlink:label="nktr_ContingentPaymentsReceivableBasedOnDevelopmentEvents_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Contingent Payments Receivable Based On Development Events</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_LiabilitiesToPartnersForDirectConsumerAdvertisingPayments" xlink:type="locator" xlink:label="nktr_LiabilitiesToPartnersForDirectConsumerAdvertisingPayments" />
    <label xml:lang="en-US" xlink:label="nktr_LiabilitiesToPartnersForDirectConsumerAdvertisingPayments_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Liability to AZ for DTC advertising payments.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_LiabilitiesToPartnersForDirectConsumerAdvertisingPayments" xlink:to="nktr_LiabilitiesToPartnersForDirectConsumerAdvertisingPayments_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_IncreaseDecreaseInRevenue" xlink:type="locator" xlink:label="nktr_IncreaseDecreaseInRevenue" />
    <label xml:lang="en-US" xlink:label="nktr_IncreaseDecreaseInRevenue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Increase decrease in revenue.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_IncreaseDecreaseInRevenue" xlink:to="nktr_IncreaseDecreaseInRevenue_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_LiabilitiesToPartnersForDirectConsumerAdvertisingPayments_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Liability to AZ for DTC advertising payments</label>
    <label xml:lang="en-US" xlink:label="nktr_LiabilitiesToPartnersForDirectConsumerAdvertisingPayments_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities To Partners For Direct Consumer Advertising Payments</label>
    <label xml:lang="en-US" xlink:label="nktr_IncreaseDecreaseInRevenue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reduction of revenue</label>
    <label xml:lang="en-US" xlink:label="nktr_IncreaseDecreaseInRevenue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Increase Decrease In Revenue</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredRevenue" xlink:type="locator" xlink:label="us-gaap_DeferredRevenue" />
    <label xml:lang="en-US" xlink:label="us-gaap_DeferredRevenue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred revenue</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredRevenue" xlink:to="us-gaap_DeferredRevenue_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_DeferredRevenue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Revenue</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_PotentialRoyaltyReductionOnSalesToRepayPostApprovalStudyIfRequired" xlink:type="locator" xlink:label="nktr_PotentialRoyaltyReductionOnSalesToRepayPostApprovalStudyIfRequired" />
    <label xml:lang="en-US" xlink:label="nktr_PotentialRoyaltyReductionOnSalesToRepayPostApprovalStudyIfRequired_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Potential royalty reduction on sales to repay post-approval study if required.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_PotentialRoyaltyReductionOnSalesToRepayPostApprovalStudyIfRequired" xlink:to="nktr_PotentialRoyaltyReductionOnSalesToRepayPostApprovalStudyIfRequired_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_PercentageOfPostApprovalStudyCostsToRepay" xlink:type="locator" xlink:label="nktr_PercentageOfPostApprovalStudyCostsToRepay" />
    <label xml:lang="en-US" xlink:label="nktr_PercentageOfPostApprovalStudyCostsToRepay_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Percentage of post approval study costs to repay.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_PercentageOfPostApprovalStudyCostsToRepay" xlink:to="nktr_PercentageOfPostApprovalStudyCostsToRepay_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_PotentialReductionInFutureRoyaltyPaymentsToRepayPostApprovalStudies" xlink:type="locator" xlink:label="nktr_PotentialReductionInFutureRoyaltyPaymentsToRepayPostApprovalStudies" />
    <label xml:lang="en-US" xlink:label="nktr_PotentialReductionInFutureRoyaltyPaymentsToRepayPostApprovalStudies_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Potential reduction in future royalty payments to repay post approval studies.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_PotentialReductionInFutureRoyaltyPaymentsToRepayPostApprovalStudies" xlink:to="nktr_PotentialReductionInFutureRoyaltyPaymentsToRepayPostApprovalStudies_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_PotentialRoyaltyReductionOnSalesToRepayPostApprovalStudyIfRequired_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Potential reduction in U.S. royalty rate for repayment</label>
    <label xml:lang="en-US" xlink:label="nktr_PotentialRoyaltyReductionOnSalesToRepayPostApprovalStudyIfRequired_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Potential Royalty Reduction On Sales To Repay Post Approval Study If Required</label>
    <label xml:lang="en-US" xlink:label="nktr_PercentageOfPostApprovalStudyCostsToRepay_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage of post approval study costs to repay</label>
    <label xml:lang="en-US" xlink:label="nktr_PercentageOfPostApprovalStudyCostsToRepay_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Percentage Of Post Approval Study Costs To Repay</label>
    <label xml:lang="en-US" xlink:label="nktr_PotentialReductionInFutureRoyaltyPaymentsToRepayPostApprovalStudies_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maximum potential reduction in royalties</label>
    <label xml:lang="en-US" xlink:label="nktr_PotentialReductionInFutureRoyaltyPaymentsToRepayPostApprovalStudies_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Potential Reduction In Future Royalty Payments To Repay Post Approval Studies</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_RevenueRecognitionMilestoneMethodRevenueRecognized" xlink:type="locator" xlink:label="us-gaap_RevenueRecognitionMilestoneMethodRevenueRecognized" />
    <label xml:lang="en-US" xlink:label="us-gaap_RevenueRecognitionMilestoneMethodRevenueRecognized_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Development milestones achieved</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RevenueRecognitionMilestoneMethodRevenueRecognized" xlink:to="us-gaap_RevenueRecognitionMilestoneMethodRevenueRecognized_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_RevenueRecognitionMilestoneMethodRevenueRecognized_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Revenue Recognition Milestone Method Revenue Recognized</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_ConsiderationReceivedForProductDelivered" xlink:type="locator" xlink:label="nktr_ConsiderationReceivedForProductDelivered" />
    <label xml:lang="en-US" xlink:label="nktr_ConsiderationReceivedForProductDelivered_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Consideration received for product delivered.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_ConsiderationReceivedForProductDelivered" xlink:to="nktr_ConsiderationReceivedForProductDelivered_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_ConsiderationReceivedForProductDelivered_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Consideration received for product delivered in 2013</label>
    <label xml:lang="en-US" xlink:label="nktr_ConsiderationReceivedForProductDelivered_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Consideration Received For Product Delivered</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_DevelopmentMilestonePaymentReceived" xlink:type="locator" xlink:label="nktr_DevelopmentMilestonePaymentReceived" />
    <label xml:lang="en-US" xlink:label="nktr_DevelopmentMilestonePaymentReceived_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Development milestone payment received.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_DevelopmentMilestonePaymentReceived" xlink:to="nktr_DevelopmentMilestonePaymentReceived_lbl" />
    <loc xlink:href="nktr-20151231.xsd#nktr_PaymentForReimbursementOfCosts" xlink:type="locator" xlink:label="nktr_PaymentForReimbursementOfCosts" />
    <label xml:lang="en-US" xlink:label="nktr_PaymentForReimbursementOfCosts_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Payment made to Bayer for cost of Phase 3 clinical trial.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_PaymentForReimbursementOfCosts" xlink:to="nktr_PaymentForReimbursementOfCosts_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_DevelopmentMilestonePaymentReceived_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Development milestone achieved in 2013</label>
    <label xml:lang="en-US" xlink:label="nktr_DevelopmentMilestonePaymentReceived_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Development Milestone Payment Received</label>
    <label xml:lang="en-US" xlink:label="nktr_PaymentForReimbursementOfCosts_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Payment made to Bayer for cost of Phase 3 clinical trial</label>
    <label xml:lang="en-US" xlink:label="nktr_PaymentForReimbursementOfCosts_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Payment For Reimbursement Of Costs</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_PotentialDevelopmentMilestonesUponAcceptanceForReviewOfRegulatoryApproval" xlink:type="locator" xlink:label="nktr_PotentialDevelopmentMilestonesUponAcceptanceForReviewOfRegulatoryApproval" />
    <label xml:lang="en-US" xlink:label="nktr_PotentialDevelopmentMilestonesUponAcceptanceForReviewOfRegulatoryApproval_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Potential development milestones upon acceptance for review of regulatory approval.</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_PotentialDevelopmentMilestonesUponAcceptanceForReviewOfRegulatoryApproval" xlink:to="nktr_PotentialDevelopmentMilestonesUponAcceptanceForReviewOfRegulatoryApproval_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_PotentialDevelopmentMilestonesUponAcceptanceForReviewOfRegulatoryApproval_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Potential future development milestones upon acceptance for review of regulatory approval</label>
    <label xml:lang="en-US" xlink:label="nktr_PotentialDevelopmentMilestonesUponAcceptanceForReviewOfRegulatoryApproval_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Potential Development Milestones Upon Acceptance For Review Of Regulatory Approval</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredRevenueRevenueRecognized" xlink:type="locator" xlink:label="us-gaap_DeferredRevenueRevenueRecognized" />
    <label xml:lang="en-US" xlink:label="us-gaap_DeferredRevenueRevenueRecognized_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred revenue recognized</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredRevenueRevenueRecognized" xlink:to="us-gaap_DeferredRevenueRevenueRecognized_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_DeferredRevenueRevenueRecognized_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Revenue Revenue Recognized</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" />
    <label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Table]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:to="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Schedule Of Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Table]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:type="locator" xlink:label="us-gaap_IncomeStatementLocationAxis" />
    <label xml:lang="en-US" xlink:label="us-gaap_IncomeStatementLocationAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income Statement Location</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeStatementLocationAxis" xlink:to="us-gaap_IncomeStatementLocationAxis_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_IncomeStatementLocationAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Income Statement Location [Axis]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:type="locator" xlink:label="us-gaap_IncomeStatementLocationDomain" />
    <label xml:lang="en-US" xlink:label="us-gaap_IncomeStatementLocationDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income Statement Location</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeStatementLocationDomain" xlink:to="us-gaap_IncomeStatementLocationDomain_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_IncomeStatementLocationDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Income Statement Location [Domain]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_CostOfSalesMember" xlink:type="locator" xlink:label="us-gaap_CostOfSalesMember" />
    <label xml:lang="en-US" xlink:label="us-gaap_CostOfSalesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cost of Goods Sold [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CostOfSalesMember" xlink:to="us-gaap_CostOfSalesMember_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_CostOfSalesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Cost Of Sales [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ResearchAndDevelopmentExpenseMember" xlink:type="locator" xlink:label="us-gaap_ResearchAndDevelopmentExpenseMember" />
    <label xml:lang="en-US" xlink:label="us-gaap_ResearchAndDevelopmentExpenseMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Research and Development Expense [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ResearchAndDevelopmentExpenseMember" xlink:to="us-gaap_ResearchAndDevelopmentExpenseMember_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_ResearchAndDevelopmentExpenseMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Research And Development Expense [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_GeneralAndAdministrativeExpenseMember" xlink:type="locator" xlink:label="us-gaap_GeneralAndAdministrativeExpenseMember" />
    <label xml:lang="en-US" xlink:label="us-gaap_GeneralAndAdministrativeExpenseMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">General and Administrative Expense [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GeneralAndAdministrativeExpenseMember" xlink:to="us-gaap_GeneralAndAdministrativeExpenseMember_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_GeneralAndAdministrativeExpenseMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">General And Administrative Expense [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:type="locator" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" />
    <label xml:lang="en-US" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]</label>
    <label xml:lang="en-US" xlink:label="us-gaap_AllocatedShareBasedCompensationExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Total stock-based compensation</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:type="locator" xlink:label="us-gaap_EmployeeStockOptionMember" />
    <label xml:lang="en-US" xlink:label="us-gaap_EmployeeStockOptionMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock Options [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EmployeeStockOptionMember" xlink:to="us-gaap_EmployeeStockOptionMember_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_EmployeeStockOptionMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Employee Stock Option [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:type="locator" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" />
    <label xml:lang="en-US" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total unrecognized compensation costs</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized</label>
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    <label xml:lang="en-US" xlink:label="nktr_IncomeTaxesDisclosureTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Income taxes disclosure.</label>
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeTaxAuthorityAxis" xlink:type="locator" xlink:label="us-gaap_IncomeTaxAuthorityAxis" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DomesticCountryMember" xlink:type="locator" xlink:label="us-gaap_DomesticCountryMember" />
    <label xml:lang="en-US" xlink:label="us-gaap_DomesticCountryMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DomesticCountryMember" xlink:to="us-gaap_DomesticCountryMember_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_DomesticCountryMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Domestic Country [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_StateAndLocalJurisdictionMember" xlink:type="locator" xlink:label="us-gaap_StateAndLocalJurisdictionMember" />
    <label xml:lang="en-US" xlink:label="us-gaap_StateAndLocalJurisdictionMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">State [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StateAndLocalJurisdictionMember" xlink:to="us-gaap_StateAndLocalJurisdictionMember_lbl" />
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    <label xml:lang="en-US" xlink:label="nktr_IncomeTaxesDisclosureLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Income Taxes Disclosure [Line Items]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:type="locator" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" />
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_lbl" />
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    <loc xlink:href="nktr-20151231.xsd#nktr_IncomeTaxReconciliationNonDeductibleExpenseForLiabilityRelatedSaleOfFutureRoyalties" xlink:type="locator" xlink:label="nktr_IncomeTaxReconciliationNonDeductibleExpenseForLiabilityRelatedSaleOfFutureRoyalties" />
    <label xml:lang="en-US" xlink:label="nktr_IncomeTaxReconciliationNonDeductibleExpenseForLiabilityRelatedSaleOfFutureRoyalties_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to other nondeductible expenses.</label>
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract" xlink:type="locator" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract" />
    <label xml:lang="en-US" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">U.S. federal provision (benefit)</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract" xlink:to="us-gaap_EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Effective Income Tax Rate Continuing Operations Tax Rate Reconciliation [Abstract]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate" xlink:type="locator" xlink:label="us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate" />
    <label xml:lang="en-US" xlink:label="us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">At statutory rate</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate" xlink:to="us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate_lbl" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes" xlink:type="locator" xlink:label="us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:type="locator" xlink:label="us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_IncomeTaxReconciliationTaxSettlementsForeign" xlink:type="locator" xlink:label="us-gaap_IncomeTaxReconciliationTaxSettlementsForeign" />
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    <loc xlink:href="nktr-20151231.xsd#nktr_DeferredTaxAssetsFromSaleOfFutureRoyalties" xlink:type="locator" xlink:label="nktr_DeferredTaxAssetsFromSaleOfFutureRoyalties" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsResearch" xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsResearch" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost" xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost" />
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    <label xml:lang="en-US" xlink:label="nktr_DeferredTaxAssetsFromSaleOfFutureRoyalties_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Sale of future royalties</label>
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccruals" xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccruals" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredTaxAssetsOther" xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsOther" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredTaxAssetsGross" xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsGross" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredTaxAssetsValuationAllowance" xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsValuationAllowance" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredTaxAssetsNet" xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsNet" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_DeferredTaxLiabilities" xlink:type="locator" xlink:label="us-gaap_DeferredTaxLiabilities" />
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    <loc xlink:href="nktr-20151231.xsd#nktr_ValuationAllowanceRelatedToStockBasedCompensationAndExercises" xlink:type="locator" xlink:label="nktr_ValuationAllowanceRelatedToStockBasedCompensationAndExercises" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:type="locator" xlink:label="us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" />
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    <loc xlink:href="nktr-20151231.xsd#nktr_NetOperatingLossCarryforwardForIncomeTax" xlink:type="locator" xlink:label="nktr_NetOperatingLossCarryforwardForIncomeTax" />
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    <loc xlink:href="nktr-20151231.xsd#nktr_FederalResearchAndDevelopmentCreditsExpirationYear" xlink:type="locator" xlink:label="nktr_FederalResearchAndDevelopmentCreditsExpirationYear" />
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    <loc xlink:href="nktr-20151231.xsd#nktr_FederalOrphanDrugCredits" xlink:type="locator" xlink:label="nktr_FederalOrphanDrugCredits" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromCurrentPeriodTaxPositions" xlink:type="locator" xlink:label="us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromCurrentPeriodTaxPositions" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions" xlink:type="locator" xlink:label="us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions" xlink:type="locator" xlink:label="us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities" xlink:type="locator" xlink:label="us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities" />
    <label xml:lang="en-US" xlink:label="us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Settlements</label>
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations" xlink:type="locator" xlink:label="us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations" />
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    <loc xlink:href="nktr-20151231.xsd#nktr_UnrecognizedTaxBenefitsPeriodIncreaseDecreaseReasonablePeriodOfChange" xlink:type="locator" xlink:label="nktr_UnrecognizedTaxBenefitsPeriodIncreaseDecreaseReasonablePeriodOfChange" />
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    <loc xlink:href="nktr-20151231.xsd#nktr_NumberOfOperatingBusinessSegment" xlink:type="locator" xlink:label="nktr_NumberOfOperatingBusinessSegment" />
    <label xml:lang="en-US" xlink:label="nktr_NumberOfOperatingBusinessSegment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Number of operating business segment.</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:to="us-gaap_ConcentrationRiskByBenchmarkAxis_lbl" />
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskBenchmarkDomain" xlink:to="us-gaap_ConcentrationRiskBenchmarkDomain_lbl" />
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    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SalesRevenueNetMember" xlink:type="locator" xlink:label="us-gaap_SalesRevenueNetMember" />
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    <label xml:lang="en-US" xlink:label="us-gaap_SalesRevenueNetMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Sales Revenue Net [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_MajorCustomersAxis" xlink:type="locator" xlink:label="us-gaap_MajorCustomersAxis" />
    <label xml:lang="en-US" xlink:label="us-gaap_MajorCustomersAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Major Customers</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_MajorCustomersAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Major Customers [Axis]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:type="locator" xlink:label="us-gaap_NameOfMajorCustomerDomain" />
    <label xml:lang="en-US" xlink:label="us-gaap_NameOfMajorCustomerDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Name Of Major Customer</label>
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    <loc xlink:href="nktr-20151231.xsd#nktr_AstraZenecaMember" xlink:type="locator" xlink:label="nktr_AstraZenecaMember" />
    <label xml:lang="en-US" xlink:label="nktr_AstraZenecaMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Astra Zeneca [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_AstraZenecaMember" xlink:to="nktr_AstraZenecaMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_AstraZenecaMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">AstraZeneca [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_AstraZenecaMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Astra Zeneca [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_UCBPharmaMember" xlink:type="locator" xlink:label="nktr_UCBPharmaMember" />
    <label xml:lang="en-US" xlink:label="nktr_UCBPharmaMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">UCB Pharma.</label>
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    <label xml:lang="en-US" xlink:label="nktr_UCBPharmaMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">UCB [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_UCBPharmaMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">U C B Pharma [Member]</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_BayerMember" xlink:type="locator" xlink:label="nktr_BayerMember" />
    <label xml:lang="en-US" xlink:label="nktr_BayerMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Bayer [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_BayerMember" xlink:to="nktr_BayerMember_lbl" />
    <label xml:lang="en-US" xlink:label="nktr_BayerMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Bayer [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_BayerMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Bayer [Member]</label>
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    <label xml:lang="en-US" xlink:label="us-gaap_ConcentrationRiskByTypeAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Concentration Risk By Type</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskByTypeAxis" xlink:to="us-gaap_ConcentrationRiskByTypeAxis_lbl" />
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    <label xml:lang="en-US" xlink:label="us-gaap_ConcentrationRiskTypeDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Concentration Risk Type</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CustomerConcentrationRiskMember" xlink:to="us-gaap_CustomerConcentrationRiskMember_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_CustomerConcentrationRiskMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Customer Concentration Risk [Member]</label>
    <loc xlink:href="http://xbrl.sec.gov/country/2013/country-2013-01-31.xsd#country_IN" xlink:type="locator" xlink:label="country_IN" />
    <label xml:lang="en-US" xlink:label="country_IN_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">India [Member]</label>
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    <label xml:lang="en-US" xlink:label="country_IN_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">I N</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_GermanyAndNetherlandsMember" xlink:type="locator" xlink:label="nktr_GermanyAndNetherlandsMember" />
    <label xml:lang="en-US" xlink:label="nktr_GermanyAndNetherlandsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Germany and Netherlands.</label>
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    <label xml:lang="en-US" xlink:label="nktr_GermanyAndNetherlandsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Germany and Netherlands [Member]</label>
    <label xml:lang="en-US" xlink:label="nktr_GermanyAndNetherlandsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Germany And Netherlands [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:type="locator" xlink:label="us-gaap_SegmentReportingInformationLineItems" />
    <label xml:lang="en-US" xlink:label="us-gaap_SegmentReportingInformationLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Segment Reporting Information [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_SegmentReportingInformationLineItems_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_SegmentReportingInformationLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting Information [Line Items]</label>
    <label xml:lang="en-US" xlink:label="nktr_NumberOfOperatingBusinessSegment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of operating business segment</label>
    <label xml:lang="en-US" xlink:label="nktr_NumberOfOperatingBusinessSegment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Number Of Operating Business Segment</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:type="locator" xlink:label="us-gaap_ConcentrationRiskPercentage1" />
    <label xml:lang="en-US" xlink:label="us-gaap_ConcentrationRiskPercentage1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage revenue from clients</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskPercentage1" xlink:to="us-gaap_ConcentrationRiskPercentage1_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_ConcentrationRiskPercentage1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Concentration Risk Percentage1</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable" />
    <label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Entity Wide Revenue By Major Customers By Reporting Segments [Table]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable" xlink:to="us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Schedule Of Entity Wide Revenue By Major Customers By Reporting Segments [Table]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EuropeMember" xlink:type="locator" xlink:label="us-gaap_EuropeMember" />
    <label xml:lang="en-US" xlink:label="us-gaap_EuropeMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">European [Member]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EuropeMember" xlink:to="us-gaap_EuropeMember_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_EuropeMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Europe [Member]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EntityWideRevenueMajorCustomerLineItems" xlink:type="locator" xlink:label="us-gaap_EntityWideRevenueMajorCustomerLineItems" />
    <label xml:lang="en-US" xlink:label="us-gaap_EntityWideRevenueMajorCustomerLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Wide Revenue Major Customer [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EntityWideRevenueMajorCustomerLineItems" xlink:to="us-gaap_EntityWideRevenueMajorCustomerLineItems_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_EntityWideRevenueMajorCustomerLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Wide Revenue Major Customer [Line Items]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_GeographicAreasRevenuesFromExternalCustomersAbstract" xlink:type="locator" xlink:label="us-gaap_GeographicAreasRevenuesFromExternalCustomersAbstract" />
    <label xml:lang="en-US" xlink:label="us-gaap_GeographicAreasRevenuesFromExternalCustomersAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Revenue by geographic area</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GeographicAreasRevenuesFromExternalCustomersAbstract" xlink:to="us-gaap_GeographicAreasRevenuesFromExternalCustomersAbstract_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_GeographicAreasRevenuesFromExternalCustomersAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Geographic Areas Revenues From External Customers [Abstract]</label>
    <label xml:lang="en-US" xlink:label="us-gaap_Revenues_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total revenue</label>
    <loc xlink:href="nktr-20151231.xsd#nktr_PercentageOfPropertyPlantEquipmentNetInAssets" xlink:type="locator" xlink:label="nktr_PercentageOfPropertyPlantEquipmentNetInAssets" />
    <label xml:lang="en-US" xlink:label="nktr_PercentageOfPropertyPlantEquipmentNetInAssets_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation">Percentage Of Property Plant Equipment Net In Assets</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="nktr_PercentageOfPropertyPlantEquipmentNetInAssets" xlink:to="nktr_PercentageOfPropertyPlantEquipmentNetInAssets_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Property, plant and equipment, net</label>
    <label xml:lang="en-US" xlink:label="nktr_PercentageOfPropertyPlantEquipmentNetInAssets_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage of net book value of property and equipment</label>
    <label xml:lang="en-US" xlink:label="nktr_PercentageOfPropertyPlantEquipmentNetInAssets_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Percentage Of Property Plant Equipment Net In Assets</label>
    <label xml:lang="en-US" xlink:label="us-gaap_ResearchAndDevelopmentExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Research and development expenses</label>
    <label xml:lang="en-US" xlink:label="us-gaap_OperatingIncomeLoss_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Operating income (loss)</label>
    <label xml:lang="en-US" xlink:label="us-gaap_NetIncomeLoss_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net income (loss)</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EarningsPerShareAbstract" xlink:type="locator" xlink:label="us-gaap_EarningsPerShareAbstract" />
    <label xml:lang="en-US" xlink:label="us-gaap_EarningsPerShareAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net income (loss) per share</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EarningsPerShareAbstract" xlink:to="us-gaap_EarningsPerShareAbstract_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_EarningsPerShareAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Earnings Per Share [Abstract]</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EarningsPerShareBasic" xlink:type="locator" xlink:label="us-gaap_EarningsPerShareBasic" />
    <label xml:lang="en-US" xlink:label="us-gaap_EarningsPerShareBasic_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Basic</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EarningsPerShareBasic" xlink:to="us-gaap_EarningsPerShareBasic_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_EarningsPerShareBasic_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Earnings Per Share Basic</label>
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2015/elts/us-gaap-2015-01-31.xsd#us-gaap_EarningsPerShareDiluted" xlink:type="locator" xlink:label="us-gaap_EarningsPerShareDiluted" />
    <label xml:lang="en-US" xlink:label="us-gaap_EarningsPerShareDiluted_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Diluted</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EarningsPerShareDiluted" xlink:to="us-gaap_EarningsPerShareDiluted_lbl" />
    <label xml:lang="en-US" xlink:label="us-gaap_EarningsPerShareDiluted_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Earnings Per Share Diluted</label>
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