Exhibit 1.1

THERAVANCE, INC.

(a Delaware corporation)

3% Subordinated Convertible Notes due 2015

PURCHASE AGREEMENT

Dated:  January 16, 2008

THERAVANCE, INC.

(a Delaware corporation)

$150,000,000

3% Subordinated Convertible Notes due 2015

PURCHASE AGREEMENT

January 16, 2008

MERRILL LYNCH & CO.

Merrill Lynch, Pierce, Fenner & Smith

Incorporated

GOLDMAN, SACHS & CO.

Goldman, Sachs & Co.

as Representatives of the several Underwriters

c/o Merrill Lynch & Co.

Merrill Lynch, Pierce Fenner & Smith

Incorporated

4 World Financial Center

New York, New York  10080

Goldman, Sachs & Co.

85 Broad Street

New York, New York  10004

Ladies and Gentlemen:

Theravance, Inc., a Delaware corporation (the “Company”), confirms its agreement with Merrill Lynch & Co., Merrill Lynch, Pierce, Fenner & Smith Incorporated (“Merrill Lynch”), Goldman, Sachs & Co. (“Goldman, Sachs”) and each of the other Underwriters, if any, named in Schedule A hereto (collectively, the “Underwriters,” which term shall also include any underwriter substituted as hereinafter provided in Section 10 hereof), for whom Merrill Lynch and Goldman, Sachs are acting as representatives (in such capacity, the “Representatives”), with respect to (i) the sale by the Company and the purchase by the Underwriters, acting severally and not jointly, of the respective principal amounts set forth in Schedule A of $150,000,000 aggregate principal amount of the Company’s 3% Subordinated Convertible Notes due 2015 (the “Notes”), and (ii) the grant by the Company to the Underwriters, acting severally and not jointly, of the option described in Section 2(b) hereof to purchase all or any part of an additional $22,500,000 aggregate principal amount of the Notes to cover overallotments, if any. The aforesaid $150,000,000 aggregate principal amount of the Notes (the “Initial Securities”) to be purchased by the Underwriters and all or any part of the $22,500,000 aggregate principal amount of the Notes subject to the option described in Section 2(b) hereof (the “Option Securities”) are hereinafter called, collectively, the “Securities.”  The Securities are to be issued pursuant to an indenture dated on or about January 23, 2008 (the “Indenture”) between the Company and The Bank of New York, as trustee (the “Trustee”).  Securities issued in book-entry form will be issued to Cede & Co. as nominee of The Depository Trust Company (“DTC”) pursuant to a letter of representations (the “DTC Agreement”), between the Company and DTC.

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The Securities are convertible into shares of common stock, par value $0.01 per share (the “Common Stock”), of the Company (the “Underlying Common Stock”) in accordance with the terms of the Securities and the Indenture, at the initial conversion rate specified in the Final Term Sheet, subject to adjustment as set forth in the Indenture.

The Company understands that the Underwriters propose to make a public offering of the Securities as soon as the Representatives deem advisable after this Agreement has been executed and delivered and the Indenture has been qualified under the Trust Indenture Act of 1939, as amended (the “1939 Act”).

The Company has filed with the Securities and Exchange Commission (the “Commission”) an automatic shelf registration statement on Form S-3 (No. 333-148677), including the related preliminary prospectus or prospectuses, which registration statement became effective upon filing under Rule 462(e) of the rules and regulations of the Commission (the “1933 Act Regulations”) under the Securities Act of 1933, as amended (the “1933 Act”).  Such registration statement covers the registration of the Securities and the Underlying Common Stock under the 1933 Act. Promptly after execution and delivery of this Agreement, the Company will prepare and file a prospectus in accordance with the provisions of Rule 430B (“Rule 430B”) of the 1933 Act Regulations and paragraph (b) of Rule 424 (“Rule 424(b)”) of the 1933 Act Regulations.  Any information included in such prospectus that was omitted from such registration statement at the time it became effective but that is deemed to be part of and included in such registration statement pursuant to Rule 430B is referred to as “Rule 430B Information.”  Each prospectus used in connection with the offering of the Securities that omitted Rule 430B Information, is herein called a “Preliminary Prospectus.”  Such registration statement, at any given time, including the amendments thereto to such time, the exhibits and any schedules thereto at such time, the documents incorporated by reference therein pursuant to Item 12 of Form S-3 under the 1933 Act at such time and the documents otherwise deemed to be a part thereof or included therein by 1933 Act Regulations, is herein called the “Registration Statement.”  The Registration Statement at the time it originally became effective is herein called the “Original Registration Statement.”  The final prospectus in the form first furnished to the Underwriters for use in connection with the offering of the Securities, including the documents incorporated by reference therein pursuant to Item 12 of Form S-3 under the 1933 Act at the time of the execution of this Agreement and any Preliminary Prospectuses that form a part thereof, is herein called the “Prospectus.”  For purposes of this Agreement, all references to the Registration Statement, any Preliminary Prospectus, the Statutory Prospectus (as hereinafter defined), the Prospectus or any Issuer Free Writing Prospectus (as hereinafter defined) or any amendment or supplement to any of the foregoing shall be deemed to include the copy filed with the Commission pursuant to its Electronic Data Gathering, Analysis and Retrieval system (“EDGAR”).

All references in this Agreement to financial statements and schedules and other information which is “contained,” “included” or “stated” in the Registration Statement, any Preliminary Prospectus, the Statutory Prospectus or the Prospectus (or other references of like import) shall be deemed to mean and include all such financial statements and schedules and other information which is incorporated by reference in or otherwise deemed by 1933 Act Regulations to be a part of or included in the Registration Statement, any Preliminary Prospectus, the Statutory Prospectus or the Prospectus, as the case may be; and all references in this Agreement to amendments or supplements to the Registration Statement, any Preliminary Prospectus, the Statutory Prospectus or the Prospectus shall be deemed to mean and include the filing of any document under the Securities Exchange Act of 1934 (the “1934 Act”) which is incorporated by reference in or otherwise deemed by 1933 Act Regulations to be a part of or included in the Registration Statement, such Preliminary Prospectus, the Statutory Prospectus or the Prospectus, as the case may be.

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SECTION 1.           Representations and Warranties.

(a)           Representations and Warranties by the Company.  The Company represents and warrants to each Underwriter as of the date hereof, the Applicable Time referred to in Section 1(a)(ii) hereof and as of the Closing Time referred to in Section 2(c) hereof, and as of each Date of Delivery (if any) referred to in Section 2(b) hereof, and agrees with each Underwriter, as follows:

(i)            Status as a Well-Known Seasoned Issuer. (A) At the time of filing the Original Registration Statement, (B) at the time of the most recent amendment thereto for the purposes of complying with Section 10(a)(3) of the 1933 Act (whether such amendment was by post-effective amendment, incorporated report filed pursuant to Section 13 or 15(d) of the 1934 Act or form of prospectus), (C) at the time the Company or any person acting on its behalf (within the meaning, for this clause only, of Rule 163(c) of the 1933 Act Regulations) made any offer relating to the Securities in reliance on the exemption of Rule 163 of the 1933 Act Regulations and (D) at the date hereof, the Company was and is a “well-known seasoned issuer” as defined in Rule 405 of the 1933 Act Regulations (“Rule 405”), including not having been and not being an “ineligible issuer” as defined in Rule 405.   The Registration Statement is an “automatic shelf registration statement,” as defined in Rule 405, and the Securities, since their registration on the Registration Statement, have been and remain eligible for registration by the Company on a Rule 405 “automatic shelf registration statement.”  The Company has not received from the Commission any notice pursuant to Rule 401(g)(2) of the 1933 Act Regulations objecting to the use of the automatic shelf registration statement form.

At the time of filing the Original Registration Statement, at the earliest time thereafter that the Company or another offering participant made a bona fide offer (within the meaning of Rule 164(h)(2) of the 1933 Act Regulations) of the Securities and at the date hereof, the Company was not and is not an “ineligible issuer,” as defined in Rule 405.

(ii)           Registration Statement, Prospectus and Disclosure at Time of Sale.  The Original Registration Statement became effective upon filing under Rule 462(e) of the 1933 Act Regulations (“Rule 462(e)”) on January 15, 2008, and any post-effective amendment thereto also became effective upon filing under Rule 462(e).  No stop order suspending the effectiveness of the Registration Statement has been issued under the 1933 Act and no proceedings for that purpose have been instituted or are pending or, to the knowledge of the Company, are contemplated by the Commission, and any request on the part of the Commission for additional information has been complied with.

Any offer that is a written communication relating to the Securities made prior to the filing of the Original Registration Statement by the Company or any person acting on its behalf (within the meaning, for this paragraph only, of Rule 163(c) of the 1933 Act Regulations) has been filed with the Commission in accordance with the exemption provided by Rule 163 of the 1933 Act Regulations (“Rule 163”) and otherwise complied with the requirements of Rule 163, including without limitation the legending requirement, to qualify such offer for the exemption from Section 5(c) of the 1933 Act provided by Rule 163.

At the respective times the Original Registration Statement and each amendment thereto became effective, at each deemed effective date with respect to the Underwriters pursuant to Rule 430B(f)(2) of the 1933 Act Regulations, at the Applicable Time and at the Closing Time (and, if any Option Securities are purchased, at the Date of Delivery), the Registration Statement complied and will comply in all material respects with the requirements of the 1933 Act and the 1933 Act Regulations, and the 1939 Act and the rules and regulations of the Commission

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thereunder (the “1939 Act Regulations”), and did not and will not contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading.

Neither the Prospectus nor any amendments or supplements thereto, at the time the Prospectus or any such amendment or supplement was issued and at the Closing Time and, if any Option Securities are purchased, at the Date of Delivery, included or will include an untrue statement of a material fact or omitted or will omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading.

Each Preliminary Prospectus (including the prospectus or prospectuses filed as part of the Original Registration Statement or any amendment thereto) complied when so filed in all material respects with the 1933 Act Regulations and each Preliminary Prospectus and the Prospectus delivered to the Underwriters for use in connection with this offering was identical to the electronically transmitted copies thereof filed with the Commission pursuant to EDGAR, except to the extent permitted by Regulation S-T.

As of the Applicable Time (as hereinafter defined), neither (x) the Issuer General Use Free Writing Prospectus(es) (as defined below) issued at or prior to the Applicable Time and the Preliminary Prospectus all considered together (collectively, the “General Disclosure Package”), nor (y) any individual Issuer Limited Use Free Writing Prospectus (if any), when considered together with the General Disclosure Package, included any untrue statement of a material fact or omitted to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading.

As used in this subsection and elsewhere in this Agreement:

“Applicable Time” means  8 pm (Eastern time) on January 16, 2008 or such other time as agreed by the Company and the Representatives.

“Business Day” means any weekday that is not a day on which banking institutions in the City of New York are authorized or obligated to close.

“Issuer Free Writing Prospectus” means any “issuer free writing prospectus,” as defined in Rule 433 of the 1933 Act Regulations (“Rule 433”), relating to the Securities that (i) is required to be filed with the Commission by the Company, including the Final Term Sheet, (ii) is a “road show that is a written communication” within the meaning of Rule 433(d)(8)(i), whether or not required to be filed with the Commission or (iii) is exempt from filing pursuant to Rule 433(d)(5)(i) because it contains a description of the Securities or of the offering that does not reflect the final terms, in each case in the form filed or required to be filed with the Commission or, if not required to be filed, in the form retained in the Company’s records pursuant to Rule 433(g).

“Issuer General Use Free Writing Prospectus” means any Issuer Free Writing Prospectus that is intended for general distribution to prospective investors, as evidenced by its being specified in Schedule B hereto.

“Issuer Limited Use Free Writing Prospectus” means any Issuer Free Writing Prospectus that is not an Issuer General Use Free Writing Prospectus.

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“Statutory Prospectus” as of any time means the prospectus relating to the Securities that is included in the Registration Statement immediately prior to that time, including any document incorporated by reference therein and any Preliminary Prospectus or other prospectus deemed to be a part thereof.

Each Issuer Free Writing Prospectus, as of its issue date and at all subsequent times through the completion of the public offer and sale of the Securities or until any earlier date that the issuer notified or notifies the Representatives as described in Section 3(e), did not, does not and will not include any information that conflicted, conflicts or will conflict in any material respect with the information contained in the Registration Statement or the Prospectus, including any document incorporated by reference therein and any preliminary or other prospectus deemed to be a part thereof that has not been superseded or modified.

The representations and warranties in this subsection shall not apply to statements in or omissions from the Registration Statement, the Prospectus, the Statutory Prospectus, any Preliminary Prospectus or any Issuer Free Writing Prospectus made in reliance upon and in conformity with written information furnished to the Company by any Underwriter through the Representatives expressly for use therein.

(iii)          Incorporated Documents.  The documents incorporated or deemed to be incorporated by reference in the Registration Statement and the Prospectus, when they became effective or at the time they were or hereafter are filed with the Commission, complied and will comply in all material respects with the requirements of the 1933 Act and the 1933 Act Regulations or the 1934 Act and the rules and regulations of the Commission thereunder (the “1934 Act Regulations”), as applicable, and, when read together with the other information in the Prospectus, (a) at the time the Original Registration Statement became effective, (b) at the Applicable Time, (c) at the earlier of the time the Prospectus was first used and the date and time of the first contract of sale of Securities in this offering and (d) at the Closing Time (and if any Option Securities are purchased, at the Date of Delivery), did not and will not contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading.

(iv)          Independent Accountants.  Ernst & Young LLP, which audited the financial statements and supporting schedules included in the Registration Statement or incorporated by reference in the Registration Statement, the General Disclosure Package or the Prospectus, are independent public accountants as required by the 1933 Act and the 1933 Act Regulations.

(v)           Financial Statements.  The financial statements included or incorporated by reference in the Registration Statement, the General Disclosure Package and the Prospectus, together with the related schedules and notes, present fairly the financial position of the Company and its consolidated subsidiaries at the dates indicated and the statement of operations, stockholders’ equity and cash flows of the Company and its consolidated subsidiaries for the periods specified; said financial statements have been prepared in conformity with generally accepted accounting principles (“GAAP”) applied on a consistent basis throughout the periods involved.  The supporting schedules, if any, present fairly in accordance with GAAP the information required to be stated therein.  The selected financial data and the summary financial information included in the Prospectus present fairly the information shown therein and have been compiled on a basis consistent with that of the audited financial statements included or incorporated by reference in the Registration Statement.

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(vi)          No Material Adverse Change in Business.  Since the respective dates as of which information is given in the Registration Statement, the General Disclosure Package or the Prospectus, except as otherwise stated therein, (A) there has been no material adverse change in the condition, financial or otherwise, or in the earnings, business affairs or business prospects of the Company and its subsidiaries considered as one enterprise, whether or not arising in the ordinary course of business (a “Material Adverse Effect”), (B) there have been no transactions entered into by the Company or any of its subsidiaries, other than those in the ordinary course of business, which are material with respect to the Company and its subsidiaries considered as one enterprise, and (C) except as described in the Prospectus there has been no dividend or distribution of any kind declared, paid or made by the Company on any class of its capital stock.

(vii)         Good Standing of the Company.  The Company has been duly organized and is validly existing as a corporation in good standing under the laws of the State of Delaware and has corporate power and authority to own, lease and operate its properties and to conduct its business as described in the Registration Statement, the General Disclosure Package or the Prospectus, and to enter into and perform its obligations under this Agreement; and the Company is duly qualified as a foreign corporation to transact business and is in good standing in each other jurisdiction in which such qualification is required, whether by reason of the ownership or leasing of property or the conduct of business, except where the failure so to qualify or to be in good standing would not result in a Material Adverse Effect.

(viii)        Good Standing of Subsidiaries.  The only subsidiaries of the Company are the subsidiaries listed on Schedule C hereto which, considered in the aggregate as a single subsidiary, do not constitute a “significant subsidiary” as defined in Rule 1-02 of Regulation S-X.

(ix)           Capitalization.  The authorized, issued and outstanding capital stock of the Company is as set forth in the Registration Statement, the General Disclosure Package or the Prospectus in the column entitled “Actual” under the caption “Capitalization” (except for subsequent issuances, if any, pursuant to this Agreement, pursuant to reservations, agreements or employee benefit plans referred to in the Registration Statement, the General Disclosure Package or the Prospectus or pursuant to the exercise of convertible securities or options referred to in the Registration Statement, the General Disclosure Package or the Prospectus).  The shares of issued and outstanding capital stock of the Company have been duly authorized and validly issued and are fully paid and non-assessable; none of the outstanding shares of capital stock of the Company was issued in violation of the preemptive or other similar rights of any securityholder of the Company.

(x)            Authorization of Agreement.  This Agreement has been duly authorized, executed and delivered by the Company.

(xi)           Authorization of the Indenture.  The Indenture has been duly authorized by the Company and duly qualified under the 1939 Act and, when duly executed and delivered by the Company and the Trustee, will constitute a valid and binding agreement of the Company, enforceable against the Company in accordance with its terms, except as the enforcement thereof may be limited by bankruptcy, insolvency (including, without limitation, all laws relating to fraudulent transfers), reorganization, moratorium or similar laws affecting enforcement of creditors’ rights generally and except as enforcement thereof is subject to general principles of equity (regardless of whether enforcement is considered in a proceeding in equity or at law).

(xii)          Authorization of the Securities.  The Securities have been duly authorized and, at the Closing Time, will have been duly executed by the Company and, when authenticated, issued

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and delivered in the manner provided for in the Indenture and delivered against payment of the purchase price therefor as provided in this Agreement, will constitute valid and binding obligations of the Company, enforceable against the Company in accordance with their terms, except as the enforcement thereof may be limited by bankruptcy, insolvency (including, without limitation, all laws relating to fraudulent transfers), reorganization, moratorium or similar laws affecting enforcement of creditors’ rights generally and except as enforcement thereof is subject to general principles of equity (regardless of whether enforcement is considered in a proceeding in equity or at law), and will be in the form contemplated by, and entitled to the benefits of, the Indenture.

(xiii)         Description of the Securities and the Indenture.  The Securities and the Indenture will conform in all material respects to the respective statements relating thereto contained in the Registration Statement, the General Disclosure Package and the Prospectus and will be in substantially the respective forms filed or incorporated by reference, as the case may be, as exhibits to the Registration Statement.

(xiv)        Authorization and Description of the Underlying Common Stock. The Underlying Common Stock conforms to all statements relating thereto contained or incorporated by reference in the Registration Statement, the General Disclosure Package and the Prospectus. Upon issuance and delivery of the Securities in accordance with this Agreement and the Indenture, the Securities will be convertible at the option of the holder thereof for shares of Underlying Common Stock in accordance with the terms of the Securities and the Indenture; the shares of the Underlying Common Stock issuable upon conversion of the Securities have been duly authorized and reserved for issuance upon such conversion by all necessary corporate action and such shares, when issued upon such conversion, will be validly issued and will be fully paid and non-assessable; no holder of such shares will be subject to personal liability by reason of being such a holder; and the issuance of such shares upon such conversion will not be subject to the preemptive or other similar rights of any securityholder of the Company.

(xv)         Absence of Defaults and Conflicts.  Neither the Company nor any of its subsidiaries is in violation of its charter or by-laws or in default in the performance or observance of any obligation, agreement, covenant or condition contained in any contract, indenture, mortgage, deed of trust, loan or credit agreement, note, lease or other agreement or instrument to which the Company or any of its subsidiaries is a party or by which it or any of them may be bound, or to which any of the property or assets of the Company or any of its subsidiaries is subject (collectively, “Agreements and Instruments”) except for such defaults that would not reasonably be expected to have a Material Adverse Effect; and the execution, delivery and performance of this Agreement, the Indenture, the DTC Agreement and the Securities and the consummation of the transactions contemplated herein and in the Registration Statement, the General Disclosure Package and the Prospectus (including the issuance and sale of the Securities and the use of the proceeds from the sale of the Securities as described in the Registration Statement, the General Disclosure Package and the Prospectus under the caption “Use of Proceeds,” and the issuance of the shares of Underlying Common Stock issuable upon conversion of the Securities), and compliance by the Company with its obligations hereunder and under the Indenture and the Securities have been duly authorized by all necessary corporate action and do not and will not, whether with or without the giving of notice or passage of time or both, conflict with or constitute a breach of, or default or Repayment Event (as defined below) under, or result in the creation or imposition of any lien, charge or encumbrance upon any property or assets of the Company or any of its subsidiaries pursuant to, the Agreements and Instruments (except for such conflicts, breaches, defaults or Repayment Events or liens, charges or encumbrances that would not result in a Material Adverse Effect), nor will such action result in any violation of the

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provisions of the charter or by-laws of the Company or any of its subsidiaries or any applicable law, statute, rule, regulation, judgment, order, writ or decree of any government, government instrumentality or court, domestic or foreign, having jurisdiction over the Company or any of its subsidiaries or any of their material assets, properties or operations.  As used herein, a “Repayment Event” means any event or condition which gives the holder of any note, debenture or other evidence of indebtedness (or any person acting on such holder’s behalf) the right to require the repurchase, redemption or repayment of all or a portion of such indebtedness by the Company or any of its subsidiaries.

(xvi)        Absence of Labor Dispute.  No labor dispute with the employees of the Company or any of its subsidiaries exists or, to the knowledge of the Company, is imminent, and the Company is not aware of any existing or imminent labor disturbance by the employees of any of its principal suppliers, manufacturers, customers or contractors, which, in either case, would result in a Material Adverse Effect.

(xvii)       Absence of Proceedings.  There is no claim, action, suit, proceeding, inquiry or investigation before or brought by any court or governmental agency or body, domestic or foreign, now pending, or, to the knowledge of the Company, threatened, against or affecting the Company or any of its subsidiaries, which is required to be disclosed in the Registration Statement, the General Disclosure Package and the Prospectus (other than as disclosed therein), or which would reasonably be expected to result in a Material Adverse Effect, or which would reasonably be expected to materially and adversely affect the performance by the Company of its obligations hereunder; the aggregate of all pending legal or governmental proceedings to which the Company or any of its subsidiaries is a party or of which any of their respective property or assets is the subject which are not described in the Registration Statement, General Disclosure Package and the Prospectus, including ordinary routine litigation incidental to the business, would not reasonably be expected to result in a Material Adverse Effect.

(xviii)      Accuracy of Exhibits.  There are no contracts or documents which are required to be described in the Registration Statement, the General Disclosure Package or the Prospectus or the documents incorporated by reference therein or to be filed as exhibits thereto which have not been so described and filed as required.

(xix)         Possession of Intellectual Property.  The Company owns, or otherwise possesses, sufficient rights to use all patents, patent rights, licenses, inventions, copyrights, know how (including trade secrets and other unpatented and/or unpatentable proprietary rights), trademarks, service marks, trade names or other intellectual property (collectively, “Intellectual Property”) necessary to carry on the business of the Company as described in the Registration Statement, the General Disclosure Package or the Prospectus, except where the lack of such rights would not result, singly or in the aggregate, in a Material Adverse Effect.  The Company has not received any notice, and is not otherwise aware of any infringement of or conflict with asserted rights of others with respect to any Intellectual Property, or of any valid grounds for any bona fide claim that would render any of the Company’s Intellectual Property rights invalid or inadequate to protect the interests of the Company or its subsidiaries therein, and which infringement or conflict (if the subject of any unfavorable decision, ruling or finding) or invalidity or inadequacy, singly or in the aggregate, would result in a Material Adverse Effect.

(xx)          Absence of Manipulation.  Neither the Company nor any Affiliate of the Company has taken, nor will the Company or any Affiliate take, directly or indirectly, any action which is designed to or which has constituted or which would be expected to cause or result in

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stabilization or manipulation of the price of any security of the Company to facilitate the sale or resale of the Securities.

(xxi)         Absence of Further Requirements.  No filing with, or authorization, approval, consent, license, order, registration, qualification or decree of, any court or governmental authority or agency is necessary or required for the performance by the Company of its obligations hereunder, in connection with the offering, issuance or sale of the Securities hereunder, the issuance of shares of Underlying Common Stock upon conversion of the Securities, the consummation of the transactions contemplated by this Agreement, except such as have been already obtained or as may be required under the 1933 Act or the 1933 Act Regulations, state securities laws, laws and regulations of jurisdictions outside the United States, and except for the qualification of the Indenture under the 1939 Act.

(xxii)        Possession of Licenses and Permits.  The Company and its subsidiaries possess such permits, licenses, approvals, consents and other authorizations (collectively, “Governmental Licenses”) issued by the appropriate federal, state, local or foreign regulatory agencies or bodies necessary to conduct the business of the Company as described in the Registration Statement, the General Disclosure Package or the Prospectus, except where the failure so to possess would not, singly or in the aggregate, result in a Material Adverse Effect; the Company and its subsidiaries are in compliance with the terms and conditions of all such Governmental Licenses, except where the failure so to comply would not, singly or in the aggregate, result in a Material Adverse Effect; all of the Governmental Licenses are valid and in full force and effect, except when the invalidity of such Governmental Licenses or the failure of such Governmental Licenses to be in full force and effect would not, singly or in the aggregate, result in a Material Adverse Effect; and neither the Company nor any of its subsidiaries has received any notice of proceedings relating to the revocation or modification of any such Governmental Licenses which, singly or in the aggregate, if the subject of an unfavorable decision, ruling or finding, would result in a Material Adverse Effect.

(xxiii)       Title to Property.  The Company and its subsidiaries have good and marketable title or have valid rights to lease or otherwise use all real and personal property that is material to the business of the Company, free and clear of all mortgages, pledges, liens, security interests, claims, restrictions or encumbrances of any kind except such as (a) are described in the Registration Statement, the General Disclosure Package or the Prospectus or (b) do not, singly or in the aggregate, materially affect the value of such property and do not materially interfere with the use made and proposed to be made of such property by the Company or its subsidiaries; and all of the leases and subleases material to the business of the Company and its subsidiaries, considered as one enterprise, and under which the Company or its subsidiaries holds properties described in the Registration Statement, the General Disclosure Package or the Prospectus, are in full force and effect, and neither the Company nor any of its subsidiaries has any notice of any material claim of any sort that has been asserted by anyone adverse to the rights of the Company or its subsidiaries under any of the leases or subleases mentioned above.

(xxiv)       Investment Company Act.  The Company is not required, and upon the issuance and sale of the Securities as herein contemplated and the application of the net proceeds therefrom as described in the Registration Statement, the General Disclosure Package or the Prospectus will not be required, to register as an “investment company” under the Investment Company Act of 1940, as amended (the “1940 Act”).

(xxv)        Environmental Laws.  Except as described in the Registration Statement, the General Disclosure Package, or the Prospectus and except as would not, singly or in the

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aggregate, result in a Material Adverse Effect, (A) neither the Company nor any of its subsidiaries is in violation of any federal, state, local or foreign statute, law, rule, regulation, ordinance, code, policy or rule of common law or any judicial or administrative interpretation thereof, including any judicial or administrative order, consent, decree or judgment, relating to pollution or protection of human health, the environment (including, without limitation, ambient air, surface water, groundwater, land surface or subsurface strata) or wildlife, including, without limitation, laws and regulations relating to the release or threatened release of chemicals, pollutants, contaminants, wastes, toxic substances, hazardous substances, petroleum or petroleum products, asbestos-containing materials or mold (collectively, “Hazardous Materials”) or to the manufacture, processing, distribution, use, treatment, storage, disposal, transport or handling of Hazardous Materials (collectively, “Environmental Laws”), (B) the Company and its subsidiaries have all permits, authorizations and approvals required under any applicable Environmental Laws and are each in compliance with their requirements, (C) there are no pending or, to the knowledge of the Company, threatened administrative, regulatory or judicial actions, suits, demands, demand letters, claims, liens, notices of noncompliance or violation, investigation or proceedings relating to any Environmental Law against the Company or any of its subsidiaries and (D) there are no events or circumstances that would reasonably be expected to form the basis of an order for clean-up or remediation, or an action, suit or proceeding by any private party or governmental body or agency, against or affecting the Company or any of its subsidiaries relating to Hazardous Materials or any Environmental Laws.

(xxvi)       Registration Rights.  Except for such rights as have been satisfied or waived, there are no persons with registration rights or other similar rights to have any securities registered pursuant to the Registration Statement or otherwise registered by the Company under the 1933 Act.

(xxvii)      ERISA.  Except as set forth or incorporated by reference in the Prospectus, neither the Company nor any of its subsidiaries has violated any provisions of the Employee Retirement Income Security Act of 1974, as amended, except for violations which, singly or in the aggregate, would not result in a Material Adverse Effect.

(xxviii)     Foreign Corrupt Practices Act.  Except as set forth or incorporated by reference in the Prospectus, neither the Company nor any of its subsidiaries has violated any provisions of the Foreign Corrupt Practices Act or the rules and regulations promulgated thereunder except for such violations which, singly or in the aggregate, would not result in a Material Adverse Effect.

(xxix)       Insurance.  The Company and its subsidiaries carry or are entitled to the benefits of insurance, with financially sound and reputable insurers, in such amounts and covering such risks as the Company believes is reasonably prudent, and all such insurance is in full force and effect.  The Company has no reason to believe that it or any of its subsidiaries will not be able (A) to renew its existing insurance coverage as and when such policies expire or (B) to obtain comparable coverage from similar institutions as may be necessary or appropriate to conduct its business as now conducted and at a cost that would not result in a Material Adverse Effect.

(xxx)        Accounting Controls and Disclosure Controls.  The Company and each of its subsidiaries maintain a system of internal control over financial reporting sufficient to provide reasonable assurance that (1) transactions are executed in accordance with management’s general or specific authorizations; (2) transactions are recorded as necessary to permit preparation of financial statements in conformity with GAAP and to maintain accountability for assets; (3) access to assets is permitted only in accordance with management’s general or specific authorization; and (4) the recorded accountability for assets is compared with the existing assets

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at reasonable intervals and appropriate action is taken with respect to any differences.  Except as described in the Prospectus, since the end of the Company’s most recent audited fiscal year, (I) the Company is not aware of any material weakness in the Company’s internal control over financial reporting (whether or not remediated) and (II) no change in the Company’s internal control over financial reporting that has materially affected, or is reasonably likely to materially affect, the Company’s internal control over financial reporting.  The Company and its subsidiaries employ disclosure controls and procedures that are designed to reasonably assure that information required to be disclosed by the Company in the reports that it files or submits under the 1934 Act is recorded, processed, summarized and reported, within the time periods specified in the Commission’s rules and forms, and that material information regarding the Company and its subsidiaries is accumulated and communicated to the Company’s management, including its principal executive officer or officers and principal financial officer or officers, as appropriate, to allow timely decisions regarding disclosure.

(xxxi)       Compliance with the Sarbanes-Oxley Act.  There is and has been no failure on the part of the Company or any of the Company’s directors or officers, in their capacities as such, to comply in all material respects with any provision of the Sarbanes-Oxley Act of 2002 and the rules and regulations promulgated in connection therewith (the “Sarbanes Oxley Act”), including Section 402 related to loans and Sections 302 and 906 related to certifications.

(xxxii)      Pending Proceedings and Examinations.  The Registration Statement is not the subject of a pending proceeding or examination under Section 8(d) or 8(e) of the 1933 Act, and the Company is not the subject of a pending proceeding under Section 8A of the 1933 Act in connection with the offering of the Securities.

(xxxiii)     Trials and Studies.  Any clinical trials and human studies conducted by the Company and, to the knowledge of the Company, any clinical trials and human studies conducted on behalf of the Company or in which the Company has participated were and, if still pending, are being conducted in accordance with standard medical and scientific research procedures and any applicable rules, regulations and policies of the jurisdiction in which such trials and studies are being conducted, except where the failure to be so conducted would not reasonably be expected to have a Material Adverse Effect.

(xxxiv)     Regulatory Compliance.  The Company has operated and currently is in compliance with all applicable rules, regulations and policies of the FDA, except where the failure to so operate or be in compliance would not reasonably be expected to have a Material Adverse Effect.

(b)           Officer’s Certificates.  Any certificate signed by any officer of the Company or any of its subsidiaries delivered to the Representatives or to counsel for the Underwriters shall be deemed a representation and warranty by the Company to each Underwriter as to the matters covered thereby.

SECTION 2.           Sale and Delivery to Underwriters; Closing.

(a)           Initial Securities.  On the basis of the representations and warranties herein contained and subject to the terms and conditions herein  set forth, the Company agrees to sell to each Underwriter, severally and not jointly, and each Underwriter, severally and not jointly, agrees to purchase from the Company, at a purchase price of 97% of the aggregate principal amount of the Securities (the “Purchase Price”), the aggregate principal amount of Initial Securities set forth in Schedule A opposite the name of such Underwriter plus accrued interest, if any, plus any additional principal amount of Securities which such Underwriter may become obligated to purchase pursuant to the provisions of Section 10 hereof.

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(b)           Option Securities.  In addition, on the basis of the representations and warranties herein contained and subject to the terms and conditions herein set forth, the Company hereby grants an option to the Underwriters, severally and not jointly, to purchase up to an additional $22,500,000 aggregate principal amount of Option Securities at the Purchase Price, plus accrued interest, if any, from the Closing Time to the Date of Delivery (as defined below). The option hereby granted will expire 30 days from and including the date hereof, and may be exercised in whole or in part from time to time only for the purpose of covering overallotments which may be made in connection with the offering and distribution of the Initial Securities upon written notice by the Representatives to the Company setting forth the number of Option Securities as to which the several Underwriters are then exercising the option and the time and date of payment and delivery for such Option Securities. Any such time and date of delivery (a “Date of Delivery”) shall be at least two Business Days after written notice is given as determined by the Representatives, but shall not be later than seven full Business Days after the exercise of said option, nor in any event prior to the Closing Time, as hereinafter defined.  If the option is exercised as to all or any portion of the Option Securities, each of the Underwriters, acting severally and not jointly, will purchase that proportion of the aggregate principal amount of Option Securities then being purchased which the principal amount of Initial Securities set forth in Schedule A opposite the name of such Underwriter bears to the aggregate principal amount of Initial Securities.

(c)           Payment.  Payment of the purchase price for, and delivery of the Initial Securities shall be made at the offices of Gunderson Dettmer Stough Villeneuve Franklin & Hachigian, LLP, 155 Constitution Drive, Menlo Park, California, or at such other place as shall be agreed upon by the Representatives and the Company, at 9:00 A.M. (Eastern time) on the third (fourth, if the pricing occurs after 4:30 P.M. (Eastern time) on any given day) Business Day after the date hereof (unless postponed in accordance with the provisions of Section 10), or such other time not later than ten Business Days after such date as shall be agreed upon by the Representatives and the Company (such time and date of payment and delivery being herein called “Closing Time”).

In addition, in the event that any or all of the Option Securities are purchased by the Underwriters, payment of the purchase price for, and delivery of, such Option Securities shall be made at the above-mentioned offices, or at such other place as shall be agreed upon by the Representatives and the Company, on each Date of Delivery as specified in the notice from the Representatives to the Company.

Payment shall be made to the Company by wire transfer of immediately available funds to a bank account designated by the Company, against delivery to the Representatives for the respective accounts of the Underwriters of the Securities to be purchased by them.  It is understood that each Underwriter has authorized the Representatives, for its account, to accept delivery of, receipt for, and make payment of the purchase price for, the Initial Securities and the Option Securities, if any, which it has agreed to purchase.  Merrill Lynch or Goldman, Sachs, individually and not as representatives of the Underwriters, may (but shall not be obligated to) make payment of the purchase price for the Initial Securities or the Option Securities, if any, to be purchased by any Underwriter whose funds have not been received by the Closing Time or the relevant Date of Delivery, as the case may be, but such payment shall not relieve such Underwriter from its obligations hereunder.

(d)   Denominations; Registration.  The Initial Securities and the Option Securities, if any, shall be evidenced by one or more global securities registered in the name of Cede & Co., as nominee of the DTC for the account of the Underwriters against payment to or upon the order of the Company of the purchase price by wire transfer in immediately available funds. The certificates for the Initial Securities and the Option Securities, if any, will be made available for examination and packaging by the Representatives in The City of New York not later than 10:00 A.M. (Eastern Time) on the Business Day prior to the Closing Time or the relevant Date of Delivery, as the case may be.

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SECTION 3.           Covenants of the Company.  The Company covenants with each Underwriter as follows:

(a)           Compliance with Securities Regulations and Commission Requests; Payment of Filing Fees.  The Company, subject to Section 3(b), will comply with the requirements of Rule 430B and Rule 424, as applicable, and will notify the Representatives immediately, and confirm the notice in writing, (i) when any post-effective amendment to the Registration Statement or new registration statement relating to the Securities shall become effective, or any supplement to the Prospectus or any amended Prospectus shall have been filed, (ii) of the receipt of any comments from the Commission, (iii) of any request by the Commission for any amendment to the Registration Statement or the filing of a new registration statement or any amendment or supplement to the Prospectus or any document incorporated by reference therein or otherwise deemed to be a part thereof or for additional information, (iv) of the issuance by the Commission of any stop order suspending the effectiveness of the Registration Statement or such new registration statement or of any order preventing or suspending the use of any Preliminary Prospectus, or of the suspension of the qualification of the Securities for offering or sale in any jurisdiction, or of the initiation or threatening of any proceedings for any of such purposes or of any examination pursuant to Section 8(e) of the 1933 Act concerning the Registration Statement and (v) if the Company becomes the subject of a proceeding under Section 8A of the 1933 Act in connection with the offering of the Securities.  The Company will effect the filings required under Rule 424(b), in the manner and within the time period required by Rule 424(b) (without reliance on Rule 424(b)(8)), and will take such steps as it deems necessary to ascertain promptly whether the form of prospectus transmitted for filing under Rule 424(b) was received for filing by the Commission and, in the event that it was not, it will promptly file such prospectus.  The Company will make every reasonable effort to prevent the issuance of any stop order and, if any stop order is issued, to obtain the lifting thereof at the earliest possible moment.  The Company shall pay the required Commission filing fees relating to the Securities within the time required by Rule 456(b)(1) (i) of the 1933 Act Regulations without regard to the proviso therein and otherwise in accordance with Rules 456(b) and 457(r) of the 1933 Act Regulations (including, if applicable, by updating the “Calculation of Registration Fee” table in accordance with Rule 456(b)(1)(ii) either in a post-effective amendment to the Registration Statement or on the cover page of a prospectus filed pursuant to Rule 424(b)).

(b)           Filing of Amendments and Exchange Act Documents; Preparation of Final Term Sheet.  The Company will give the Representatives notice of its intention to file or prepare any amendment to the Registration Statement or new registration statement relating to the Securities or any amendment, supplement or revision to either any Preliminary Prospectus (including any prospectus included in the Original Registration Statement or amendment thereto at the time it became effective) or to the Prospectus, whether pursuant to the 1933 Act, the 1934 Act or otherwise, and the Company will furnish the Representatives with copies of any such documents a reasonable amount of time prior to such proposed filing or use, as the case may be, and will not file or use any such document to which the Representatives or counsel for the Underwriters shall reasonably object, except as required pursuant to applicable law, legal or administrative order or process. The Company has given the Representatives notice of any filings made pursuant to the 1934 Act or 1934 Act Regulations within 48 hours prior to the Applicable Time; the Company will give the Representatives notice of its intention to make any such filing from the Applicable Time to the Closing Time and will furnish the Representatives with copies of any such documents a reasonable amount of time prior to such proposed filing and will not file or use any such document to which the Representatives or counsel for the Underwriters shall reasonably object, except as required pursuant to applicable law, legal or administrative order or process.  The Company will prepare a final term sheet (the “Final Term Sheet”), attached hereto as Schedule E, reflecting the final terms of the Securities, in form and substance satisfactory to the Representatives, and shall file such Final Term Sheet as an “issuer free writing prospectus” pursuant to Rule 433 prior to the date that is two Business Days after the date hereof; provided that the Company shall furnish the Representatives with

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copies of such Final Term Sheet a reasonable amount of time prior to such proposed filing (and in any event prior to the Applicable Time) and will not use or file any such document to which the Representatives or counsel to the Underwriters shall reasonably object.

(c)           Delivery of Registration Statements.  The Company has furnished or will deliver to the Representatives and counsel for the Underwriters, without charge, signed copies of the Original Registration Statement and of each amendment thereto (including exhibits filed therewith or incorporated by reference therein and documents incorporated or deemed to be incorporated by reference therein or otherwise deemed to be a part thereof) and signed copies of all consents and certificates of experts, and will also deliver to the Representatives, without charge, a conformed copy of the Original Registration Statement and of each amendment thereto (without exhibits) for each of the Underwriters.  The copies of the Original Registration Statement and each amendment thereto furnished to the Underwriters will be identical to the electronically transmitted copies thereof filed with the Commission pursuant to EDGAR, except to the extent permitted by Regulation S-T.

(d)           Delivery of Prospectuses.  The Company has delivered to each Underwriter, without charge, as many copies of each Preliminary Prospectus as such Underwriter reasonably requested, and the Company hereby consents to the use of such copies for purposes permitted by the 1933 Act.  The Company will furnish to each Underwriter, without charge, during the period when the Prospectus is required to be delivered under the 1933 Act, such number of copies of the Prospectus (as amended or supplemented) as such Underwriter may reasonably request.  The Prospectus and any amendments or supplements thereto furnished to the Underwriters will be identical to the electronically transmitted copies thereof filed with the Commission pursuant to EDGAR, except to the extent permitted by Regulation S-T.

(e)           Continued Compliance with Securities Laws.  The Company will comply with the 1933 Act and the 1933 Act Regulations, the 1934 Act and the 1934 Act Regulations and the 1939 Act and the 1939 Act Regulations so as to permit the completion of the distribution of the Securities as contemplated in this Agreement and in the Prospectus.  If at any time when a prospectus is required by the 1933 Act to be delivered in connection with sales of the Securities, any event shall occur or condition shall exist as a result of which it is necessary, in the opinion of counsel for the Underwriters or for the Company, to amend the Registration Statement or amend or supplement the Prospectus in order that the Prospectus will not include any untrue statements of a material fact or omit to state a material fact necessary in order to make the statements therein not misleading in the light of the circumstances existing at the time it is delivered to a purchaser, or if it shall be necessary, in the opinion of such counsel, at any such time to amend the Registration Statement or to file a new registration statement or amend or supplement the Prospectus in order to comply with the requirements of the 1933 Act or the 1933 Act Regulations, the Company will promptly prepare and file with the Commission, subject to Section 3(b), such amendment, supplement or new registration statement as may be necessary to correct such statement or omission or to comply with such requirements, the Company will use its best efforts to have such amendment or new registration statement declared effective as soon as practicable (if it is not an automatic shelf registration statement with respect to the Securities) and the Company will furnish to the Underwriters such number of copies of such amendment, supplement or new registration statement as the Underwriters may reasonably request.  If at any time following issuance of an Issuer Free Writing Prospectus there occurred or occurs an event or development as a result of which such Issuer Free Writing Prospectus conflicted or would conflict in any material respect with the information contained in the Registration Statement or included or would include an untrue statement of a material fact or omitted or would omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances prevailing at that subsequent time, not misleading, the Company will promptly notify the Representatives and will promptly amend or supplement, at its own expense, such Issuer Free Writing Prospectus to eliminate or correct such conflict, untrue statement or omission.

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(f)            Blue Sky Qualifications.  The Company will cooperate with the Underwriters to qualify the Securities and the shares of Underlying Common Stock for offering and sale under the applicable securities laws of such states and other jurisdictions (domestic or foreign) as the Representatives may designate and to maintain such qualifications in effect for a period of not less than one year from the date hereof; provided, however, that the Company shall not be obligated to file any general consent to service of process or to qualify as a foreign corporation or as a dealer in securities in any jurisdiction in which it is not so qualified or to subject itself to taxation in respect of doing business in any jurisdiction in which it is not otherwise so subject.

(g)           Rule 158.  The Company will timely file such reports pursuant to the 1934 Act as are necessary in order to make generally available to its securityholders as soon as practicable an earnings statement for the purposes of, and to provide to the Underwriters the benefits contemplated by, the last paragraph of Section 11(a) of the 1933 Act.

(h)           Use of Proceeds.  The Company will use the net proceeds received by it from the sale of the Securities in the manner specified in the Prospectus under “Use of Proceeds.”

(i)            Restriction on Sale of Securities.  During a period of 90 days from the date of the Prospectus, the Company will not, without the prior written consent of the Representatives, directly or indirectly, offer pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase or otherwise transfer or dispose of any share of Common Stock or any securities convertible into or exercisable or exchangeable for Common Stock or file any registration statement under the 1933 Act with respect to any of the foregoing or (ii) enter into any swap or any other agreement or any transaction that transfers, in whole or in part, directly or indirectly, the economic consequence of ownership of the Common Stock, whether any such swap or transaction described in clause (i) or (ii) above is to be settled by delivery of Common Stock or such other securities, in cash or otherwise.  The foregoing sentence shall not apply to the (A) Securities to be sold hereunder, (B) the issuance and sale of common stock by the Company to GSK pursuant to GSK’s exercise of its pro rata rights following the end of each calendar quarter to purchase its pro rata portion of shares issued by the Company in the preceding quarter (other than the Securities), (C) any shares of Common Stock issued pursuant to outstanding options or other rights under the Company’s existing stock option plans or other employee benefit plans, in each case as described in the Prospectus, (D) any options to purchase shares of Common Stock granted under the Company’s existing stock option plans or other employee benefit plans, in each case as described in the Prospectus; provided that such options shall not be vested and exercisable prior to the expiration of the lock-up period as described in Exhibit B hereto, except that ordinary course replenishment and promotion stock option grants and restricted stock awards to be made on January 29, February 1, March 1 and April 1 may vest on a monthly basis following their grant, (E) any shares of Common Stock issued by the Company upon the exercise of any other option or warrant or the conversion of a security outstanding on the date hereof and referred to in the Prospectus or (F) any shares of Common Stock issued by the Company pursuant to the Company’s Employee Stock Purchase Plan as described in the Prospectus.

(j)            Reservation of Securities. The Company will reserve and keep available at all times, free of preemptive or other similar rights, a sufficient number of shares of Common Stock, for the purposes of enabling the Company to satisfy any obligations to issue Underlying Common Stock upon conversion of the Securities.

(k)           Reporting Requirements.  The Company, during the period when the Prospectus is required to be delivered under the 1933 Act, will file all documents required to be filed with the Commission pursuant to the 1934 Act within the time periods required by the 1934 Act and the 1934 Act Regulations.

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(l)            Listing. The Company will use its best efforts to effect and maintain the listing of the Underlying Common Stock issuable upon conversion of the Securities on the Nasdaq Global Market.

(m)          DTC. The Company will cooperate with the Underwriter to permit the offered Securities to be eligible for clearance and settlement through the facilities of the DTC.

(n)           Issuer Free Writing Prospectuses.  The Company represents and agrees that, unless it obtains the prior written consent of the Representatives, and each Underwriter represents and agrees that, unless it obtains the prior written consent of the Company and the other Underwriter, it has not made and will not make any offer relating to the Securities that would constitute an “issuer free writing prospectus,” as defined in Rule 433, or that would otherwise constitute a “free writing prospectus,” as defined in Rule 405, required to be filed with the Commission.  Any such free writing prospectus consented to by the Company and the Underwriters are hereinafter referred to as a “Permitted Free Writing Prospectus.”  The Company represents that it has treated or agrees that it will treat each Permitted Free Writing Prospectus as an “issuer free writing prospectus,” as defined in Rule 433,  and has complied and will comply with the requirements of Rule 433 applicable to any Permitted Free Writing Prospectus, including timely filing with the Commission where required, legending and record keeping.

SECTION 4.           Payment of Expenses.

(a)           Expenses.  The Company will pay or cause to be paid all expenses incident to the performance of its obligations under this Agreement, including (i) the preparation, printing and filing of the Registration Statement (including financial statements and exhibits) as originally filed and of each amendment thereto, (ii) the preparation, printing and delivery to the Underwriters of this Agreement, any Agreement among Underwriters, the Indenture, the Securities and such other documents as may be required in connection with the offering, purchase, sale, issuance or delivery of the Securities or the issuance or delivery of the Underlying Common Stock issuable upon conversion thereof, (iii) the preparation, issuance and delivery of the certificates for the Securities to the Underwriters, including any stock or other transfer taxes, any stamp or other duties payable upon the sale, issuance and delivery of the Securities to the Underwriters and the certificates for the Underlying Common Stock upon conversion thereof, (iv) the fees and disbursements of the Company’s counsel, accountants and other advisors, (v) the qualification of the Securities and the Underlying Common Stock under securities laws in accordance with the provisions of Section 3(f) hereof, including filing fees and the reasonable fees and disbursements of counsel for the Underwriters in connection therewith and in connection with the preparation of the Blue Sky Survey and any supplement thereto, (vi) the printing and delivery to the Underwriters of copies of each Preliminary Prospectus, any Permitted Free Writing Prospectus and of the Prospectus and any amendments or supplements thereto and any costs associated with electronic delivery of any of the foregoing by the Underwriters to investors, (vii) the preparation, printing and delivery to the Underwriters of copies of the Blue Sky Survey and any supplement thereto, (viii) the fees and expenses of any transfer agent or registrar for the Securities, (ix)  the costs and expenses of the Company relating to investor presentations on any “road show” undertaken in connection with the marketing of the Securities, including without limitation, expenses associated with the production of road show slides and graphics, fees and expenses of any consultants engaged with the Company’s consent in connection with the road show presentations, travel and lodging expenses of the officers of the Company and any such consultants, and one-third of the cost of aircraft and other transportation chartered with the Company’s consent in connection with the road show (x) the filing fees incident to, and the reasonable fees and disbursements of counsel to the Underwriters in connection with, the review by the Financial Industry Regulatory Authority (“FINRA”) of the terms of the sale of the Securities, (xi) the fees and expenses incurred in connection with the inclusion of the Underlying Common Stock issuable upon conversion of the Securities in the Nasdaq Global Market, (xii) the costs and expenses associated with the reforming of any contracts for sale of the Securities made by the Underwriters caused by a breach of the representation

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contained in the third paragraph of Section 1(a)(ii), and (xiii) the fees and expenses of the Trustee, including the fees and disbursements of counsel for the Trustee in connection with the Indenture and the Securities.  It is understood that, subject to this section and Section 4(b), the Underwriters will pay all of their costs and expenses, including fees and disbursements of their counsel, any travel and lodging expenses incurred by them in connection with any road show presentations and any advertising expenses connected with any offers they may make.

(b)           Termination of Agreement.  If this Agreement is terminated by the Representatives in accordance with the provisions of Section 5, Section 9(a)(i) or Section 11 hereof, the Company shall reimburse the Underwriters for all of their out-of-pocket expenses, including the reasonable fees and disbursements of counsel for the Underwriters.

SECTION 5.           Conditions of Underwriters’ Obligations.  The obligations of the several Underwriters hereunder are subject to the accuracy of the representations and warranties of the Company contained in Section 1 hereof or in certificates of any officer of the Company delivered pursuant to the provisions hereof, to the performance by the Company of its covenants and other obligations hereunder that are required to be performed or satisfied by it at or prior to the Closing Time, and to the following further conditions:

(a)           Effectiveness of Registration Statement; Filing of Prospectus; Payment of Filing Fee.  The Registration Statement has become effective and at Closing Time no stop order suspending the effectiveness of the Registration Statement shall have been issued under the 1933 Act or proceedings therefor initiated or threatened by the Commission, and any request on the part of the Commission for additional information shall have been complied with to the reasonable satisfaction of counsel to the Underwriters.  A prospectus containing  the Rule 430B Information shall have been filed with the Commission in the manner and within the time period required by Rule 424(b) without reliance on Rule 424(b)(8) (or a post-effective amendment providing such information shall have been filed and become effective in accordance with the requirements of Rule 430B).  The Final Term Sheet and any other material required to be filed by the Company pursuant to Rule 433(d) under the Rules and Regulations, shall have been timely filed.  The Company shall have paid the required Commission filing fees relating to the Securities within the time period required by Rule 456(1)(i) of the 1933 Act Regulations without regard to the proviso therein and otherwise in accordance with Rules 456(b) and 457(r) of the 1933 Act Regulations and, if applicable, shall have updated the “Calculation of Registration Fee” table in accordance with Rule 456(b)(1)(ii) either in a post-effective amendment to the Registration Statement or on the cover page of a prospectus filed pursuant to Rule 424(b).

(b)           Opinions of Counsel for Company.  At Closing Time, the Representatives shall have received opinions, dated as of Closing Time, of Gunderson Dettmer Stough Villeneuve Franklin & Hachigian, LLP and Shearman & Sterling LLP, counsel for the Company, in form and substance reasonably satisfactory to counsel for the Underwriters, together with signed or reproduced copies of such letters for each of the Underwriters to the effect set forth in Exhibits A-1 and A-2 hereto, respectively, and to such further effect as counsel to the Underwriters may reasonably request.

(c)           Opinion of Counsel for Underwriters.  At Closing Time, the Representatives shall have received an opinion, dated as of Closing Time, of Davis Polk & Wardwell, counsel for the Underwriters, together with signed or reproduced copies of such letter for each of the other Underwriters in form and substance reasonably satisfactory to the Underwriters.

(d)           Officers’ Certificate.  At Closing Time, there shall not have been, since the date hereof or since the respective dates as of which information is given in the Prospectus or the General Disclosure Package, any material adverse change in the condition, financial or otherwise, or in the earnings, business

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affairs or business prospects of the Company and its subsidiaries considered as one enterprise, whether or not arising in the ordinary course of business, and the Representatives shall have received a certificate of the Chief Executive Officer or a Vice President of the Company and of the chief financial or chief accounting officer of the Company, dated as of Closing Time, to the effect that (i) there has been no such material adverse change, (ii) the representations and warranties in Section 1(a) hereof are true and correct with the same force and effect as though expressly made at and as of Closing Time, (iii) the Company has complied with all agreements and satisfied all conditions on its part to be performed or satisfied at or prior to Closing Time, and (iv) no stop order suspending the effectiveness of the Registration Statement has been issued and no proceedings for that purpose have been instituted or are pending or, to their knowledge, contemplated by the Commission.

(e)           Accountant’s Comfort Letter.  At the time of the execution of this Agreement, the Representatives shall have received from Ernst & Young LLP a letter dated such date, in form and substance reasonably satisfactory to the Representatives, together with signed or reproduced copies of such letter for each of the other Underwriters containing statements and information of the type ordinarily included in accountants’ “comfort letters” to underwriters with respect to the financial statements and certain financial information contained in the Registration Statement, the General Disclosure Package, and the Prospectus as of the Applicable Time.

(f)            Bring-down Comfort Letter.  At Closing Time, the Representatives shall have received from Ernst & Young LLP a letter, dated as of Closing Time, to the effect that they reaffirm the statements made in the letter furnished pursuant to subsection (f) of this Section, except that the specified date referred to shall be a date not more than three Business Days prior to Closing Time.

(g)           Lock-up Agreements.  At the date of this Agreement, the Representatives shall have received an agreement substantially in the form of Exhibit B hereto signed by the persons listed on Schedule D hereto.

(h)           Conditions to Purchase of Option Securities.  In the event that the Underwriters exercise their option provided in Section 2(b) hereof to purchase all or any portion of the Option Securities, the representations and warranties of the Company contained herein and the statements in any certificates furnished by the Company and its subsidiaries hereunder shall be true and correct as of each Date of Delivery and, at the relevant Date of Delivery, the Representatives shall have received:

(i) Officers’ Certificate.  A certificate, dated such Date of Delivery, of the Chief Executive Officer or a Vice President of the Company and of the chief financial or chief accounting officer of the Company confirming that the certificate delivered at the Closing Time pursuant to Section 5(d) hereof remains true and correct as of such Date of Delivery.

(ii) Opinions of Counsel for Company.  An opinion of Gunderson Dettmer Stough Villeneuve Franklin & Hachigian, LLP and Shearman & Sterling LLP, counsel for the Company, in form and substance reasonably satisfactory to counsel for the Underwriters, dated such Date of Delivery, relating to the Option Securities to be purchased on such Date of Delivery and otherwise to the same effect as the opinions required by Section 5(b) hereof.

(iii) Opinion of Counsel for Underwriters.  An opinion of Davis Polk & Wardwell, counsel for the Underwriters, dated such Date of Delivery, relating to the Option Securities to be purchased on such Date of Delivery and otherwise to the same effect as the opinion required by Section 5(c) hereof.

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(iv) Bring-down Comfort Letter.  A letter from Ernst & Young LLP, in form and substance reasonably satisfactory to the Representatives and dated such Date of Delivery, substantially in the same form and substance as the letter furnished to the Representatives pursuant to Section 5(f) hereof, except that the “specified date” in the letter furnished pursuant to this paragraph shall be a date not more than five days prior to such Date of Delivery.

(i)            Additional Documents.  At Closing Time, and at each Date of Delivery, counsel for the Underwriters shall have been furnished with such documents and opinions as they may reasonably require for the purpose of enabling them to pass upon the issuance and sale of the Securities as herein contemplated.

(j)            Termination of Agreement.  If any condition specified in this Section shall not have been fulfilled when and as required to be fulfilled, this Agreement, or, in the case of any condition to the purchase of Option Securities, on a Date of Delivery which is after the Closing Time, the obligations of the several Underwriters to purchase the relevant Option Securities, may be terminated by the Representatives by written notice to the Company at any time at or prior to the Closing Time or such Date of Delivery, as the case may be, and such termination shall be without liability of any party to any other party except as provided in Section 4 and except that Sections 1, 6, 7 and 8 shall survive any such termination and remain in full force and effect.

SECTION 6.           Indemnification.

(a)           Indemnification of Underwriters.  The Company agrees to indemnify and hold harmless each Underwriter, its affiliates, as such term is defined in Rule 501(b) under the 1933 Act (each, an “Affiliate”), and each person, if any, who controls any Underwriter within the meaning of Section 15 of the 1933 Act or Section 20 of the 1934 Act as follows:

(i)            against any and all loss, liability, claim, damage and expense whatsoever, as incurred, arising out of any untrue statement or alleged untrue statement of a material fact contained in the Registration Statement (or any amendment thereto), including the Rule 430B Information, or the omission or alleged omission therefrom of a material fact required to be stated therein or necessary to make the statements therein not misleading or arising out of any untrue statement or alleged untrue statement of a material fact included in any Preliminary Prospectus, any Issuer Free Writing Prospectus, the General Disclosure Package or the Prospectus (or any amendment or supplement thereto), or the omission or alleged omission therefrom of a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading;

(ii)           against any and all loss, liability, claim, damage and expense whatsoever, as incurred, to the extent of the aggregate amount paid in settlement of any litigation, or any investigation or proceeding by any governmental agency or body, commenced or threatened, or of any claim whatsoever based upon any such untrue statement or omission, or any such alleged untrue statement or omission; provided that (subject to Section 6(d) below) any such settlement is effected with the written consent of the Company;

(iii)          against any and all expense whatsoever, as reasonably incurred (including the fees and disbursements of counsel chosen by the Representatives), in investigating, preparing or defending against any litigation, or any investigation or proceeding by any governmental agency or body, commenced or threatened, or any claim whatsoever based upon any such untrue

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statement or omission, or any such alleged untrue statement or omission, to the extent that any such expense is not paid under (i) or (ii) above;

provided, however, that this indemnity agreement shall not apply to any loss, liability, claim, damage or expense to the extent arising out of any untrue statement or omission or alleged untrue statement or omission made in reliance upon and in conformity with written information furnished to the Company by any Underwriter directly or through the Representatives expressly for use in the Registration Statement (or any amendment thereto), including the Rule 430B Information or any Preliminary Prospectus, any Issuer Free Writing Prospectus or the Prospectus (or any amendment or supplement thereto).

(b)           Indemnification of Company, Directors and Officers.  Each Underwriter severally agrees to indemnify and hold harmless the Company, its directors, each of its officers who signed the Registration Statement, and each person, if any, who controls the Company within the meaning of Section 15 of the 1933 Act or Section 20 of the 1934 Act against any and all loss, liability, claim, damage and expense described in the indemnity contained in subsection (a) of this Section (including, without limitation, any legal or other expenses reasonably incurred in connection with defending or investigating any such action or claim), as incurred, but only with respect to untrue statements or omissions, or alleged untrue statements or omissions, made in the Registration Statement (or any amendment thereto), including the Rule 430B Information or any Preliminary Prospectus, any Issuer Free Writing Prospectus, the General Disclosure Package or the Prospectus (or any amendment or supplement thereto) in reliance upon and in conformity with written information furnished to the Company by such Underwriters directly or through the Representatives expressly for use therein.

(c)           Actions against Parties; Notification.  Each indemnified party shall give notice as promptly as reasonably practicable to each indemnifying party of any action commenced against it in respect of which indemnity may be sought hereunder, but failure to so notify an indemnifying party shall not relieve such indemnifying party from any liability hereunder to the extent it is not materially prejudiced as a result thereof and in any event shall not relieve it from any liability which it may have otherwise than on account of this indemnity agreement.  In the case of parties indemnified pursuant to Section 6(a) above, counsel to the indemnified parties shall be selected by the Representatives, and, in the case of parties indemnified pursuant to Section 6(b) above, counsel to the indemnified parties shall be selected by the Company.  An indemnifying party may participate at its own expense in the defense of any such action; provided, however, that counsel to the indemnifying party shall not (except with the consent of the indemnified party) also be counsel to the indemnified party.  In no event shall the indemnifying parties be liable for fees and expenses of more than one counsel (in addition to any local counsel) separate from their own counsel for all indemnified parties in connection with any one action or separate but similar or related actions in the same jurisdiction arising out of the same general allegations or circumstances.  No indemnifying party shall, without the prior written consent of the indemnified parties, settle or compromise or consent to the entry of any judgment with respect to any litigation, or any investigation or proceeding by any governmental agency or body, commenced or threatened, or any claim whatsoever in respect of which indemnification or contribution could be sought under this Section 6 or Section 7 hereof (whether or not the indemnified parties are actual or potential parties thereto), unless such settlement, compromise or consent (i) includes an unconditional release of each indemnified party from all liability arising out of such litigation, investigation, proceeding or claim and (ii) does not include a statement as to or an admission of fault, culpability or a failure to act by or on behalf of any indemnified party.

(d)           Settlement without Consent if Failure to Reimburse.  If at any time an indemnified party shall have requested an indemnifying party to reimburse the indemnified party for fees and expenses of counsel, such indemnifying party agrees that it shall be liable for any settlement of the nature contemplated by Section 6(a)(ii) effected without its written consent if (i) such settlement is entered into

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more than 45 days after receipt by such indemnifying party of the aforesaid request, (ii) such indemnifying party shall have received notice of the terms of such settlement at least 30 days prior to such settlement being entered into and (iii) such indemnifying party shall not have reimbursed such indemnified party in accordance with such request prior to the date of such settlement.

SECTION 7.           Contribution.  If the indemnification provided for in Section 6 hereof is for any reason unavailable to or insufficient to hold harmless an indemnified party in respect of any losses, liabilities, claims, damages or expenses referred to therein, then each indemnifying party shall contribute to the aggregate amount of such losses, liabilities, claims, damages and expenses incurred by such indemnified party, as incurred, (i) in such proportion as is appropriate to reflect the relative benefits received by the Company on the one hand and the Underwriters on the other hand from the offering of the Securities pursuant to this Agreement or (ii) if the allocation provided by clause (i) is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits referred to in clause (i) above but also the relative fault of the Company on the one hand and of the Underwriters on the other hand in connection with the statements or omissions which resulted in such losses, liabilities, claims, damages or expenses, as well as any other relevant equitable considerations.

The relative benefits received by the Company on the one hand and the Underwriters on the other hand in connection with the offering of the Securities pursuant to this Agreement shall be deemed to be in the same respective proportions as the total net proceeds from the offering of the Securities pursuant to this Agreement (before deducting expenses) received by the Company and the total underwriting discount received by the Underwriters, in each case as set forth on the cover of the Prospectus bear to the aggregate initial public offering price of the Securities as set forth on the cover of the Prospectus.

The relative fault of the Company on the one hand and the Underwriters on the other hand shall be determined by reference to, among other things, whether any such untrue or alleged untrue statement of a material fact or omission or alleged omission to state a material fact relates to information supplied by the Company or by the Underwriters and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission.

The Company and the Underwriters agree that it would not be just and equitable if contribution pursuant to this Section 7 were determined by pro rata allocation (even if the Underwriters were treated as one entity for such purpose) or by any other method of allocation which does not take account of the equitable considerations referred to above in this Section 7.  The aggregate amount of losses, liabilities, claims, damages and expenses incurred by an indemnified party and referred to above in this Section 7 shall be deemed to include any legal or other expenses reasonably incurred by such indemnified party in investigating, preparing or defending against any litigation, or any investigation or proceeding by any governmental agency or body, commenced or threatened, or any claim whatsoever based upon any such untrue or alleged untrue statement or omission or alleged omission.

Notwithstanding the provisions of this Section 7, no Underwriter shall be required to contribute any amount in excess of the amount by which the total price at which the Securities underwritten by it and distributed to the public were offered to the public exceeds the amount of any damages which such Underwriter has otherwise been required to pay by reason of any such untrue or alleged untrue statement or omission or alleged omission.

No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the 1933 Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation.

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For purposes of this Section 7, each person, if any, who controls an Underwriter within the meaning of Section 15 of the 1933 Act or Section 20 of the 1934 Act and each Underwriter’s Affiliates shall have the same rights to contribution as such Underwriter, and each director of the Company, each officer of the Company who signed the Registration Statement, and each person, if any, who controls the Company within the meaning of Section 15 of the 1933 Act or Section 20 of the 1934 Act shall have the same rights to contribution as the Company.  The Underwriters’ respective obligations to contribute pursuant to this Section 7 are several in proportion to the principal amount of Securities set forth opposite their respective names in Schedule A hereto and not joint.

SECTION 8.           Representations, Warranties and Agreements to Survive.  All representations, warranties and agreements contained in this Agreement or in certificates of officers of the Company or any of its subsidiaries submitted pursuant hereto, shall remain operative and in full force and effect regardless of (i) any investigation made by or on behalf of any Underwriter or its Affiliates, any person controlling any Underwriter, its officers or directors or any person controlling the Company, and (ii) delivery of and payment for the Securities.

SECTION 9.           Termination of Agreement.

(a)           Termination; General.  The Representatives may terminate this Agreement, by notice to the Company, at any time at or prior to Closing Time (i) if there has been, since the time of execution of this Agreement or since the respective dates as of which information is given in the Prospectus or the General Disclosure Package, any material adverse change in the condition, financial or otherwise, or in the earnings, business affairs or business prospects of the Company and its subsidiaries considered as one enterprise, whether or not arising in the ordinary course of business, or (ii) if there has occurred any material adverse change in the financial markets in the United States or the international financial markets, any outbreak of hostilities or escalation thereof or other calamity or crisis or any change or development involving a prospective change in national or international political, financial or economic conditions, in each case the effect of which is such as to make it, in the judgment of the Representatives, impracticable or inadvisable to market the Securities or to enforce contracts for the sale of the Securities, or (iii) if trading in any securities of the Company has been suspended or materially limited by the Commission or the Nasdaq Global Market, or if trading generally on the American Stock Exchange or the New York Stock Exchange or in the Nasdaq Global Market has been suspended or materially limited, or minimum or maximum prices for trading have been fixed, or maximum ranges for prices have been required, by any of said exchanges or by such system or by order of the Commission, the National Association of Securities Dealers, Inc. or any other governmental authority, or (iv)  a material disruption has occurred in securities settlement or payment or clearance services in the United States, or (v) if a commercial banking moratorium has been declared by either Federal or New York authorities.

(b)           Liabilities.  If this Agreement is terminated pursuant to this Section, such termination shall be without liability of any party to any other party except as provided in Section 4 hereof, and provided further that Sections 1, 6, 7 and 8 shall survive such termination and remain in full force and effect.

SECTION 10.         Default by One or More of the Underwriters.  If one or more of the Underwriters shall fail at Closing Time or a Date of Delivery to purchase the Securities which it or they are obligated to purchase under this Agreement (the “Defaulted Securities”), the Representatives shall have the right, within 24 hours thereafter, to make arrangements for one or more of the non-defaulting Underwriters, or any other underwriters, to purchase all, but not less than all, of the Defaulted Securities in such amounts as may be agreed upon and upon the terms herein set forth; if, however, the Representatives shall not have completed such arrangements within such 24-hour period, then:

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(a)           if the aggregate principal amount of Defaulted Securities does not exceed 10% of the aggregate principal amount of the Securities to be purchased on such date, each of the non-defaulting Underwriters shall be obligated, severally and not jointly, to purchase the full amount thereof in the proportions that their respective underwriting obligations hereunder bear to the underwriting obligations of all non-defaulting Underwriters, or

(b)           if the aggregate principal amount of Defaulted Securities exceeds 10% of the aggregate principal amount of Securities to be purchased on such date, this Agreement or, with respect to any Date of Delivery which occurs after the Closing Time, the obligation of the Underwriters to purchase and of the Company to sell the Option Securities to be purchased and sold on such Date of Delivery shall terminate without liability on the part of any non-defaulting Underwriter.

No action taken pursuant to this Section shall relieve any defaulting Underwriter from liability in respect of its default.

In the event of any such default which does not result in a termination of this Agreement or, in the case of a Date of Delivery which is after the Closing Time, which does not result in a termination of the obligation of the Underwriters to purchase and the Company to sell the relevant Option Securities, as the case may be, either (i) the Representatives or (ii) the Company shall have the right to postpone Closing Time or the relevant Date of Delivery, as the case may be, for a period not exceeding seven days in order to effect any required changes in the Registration Statement or Prospectus or in any other documents or arrangements.  As used herein, the term “Underwriter” includes any person substituted for an Underwriter under this Section 10.

SECTION 11.         Default by the Company.  If the Company shall fail at Closing Time or at the Date of Delivery to sell the Securities that it is obligated to sell hereunder, then this Agreement shall terminate without any liability on the part of any nondefaulting party; provided, however, that the provisions of Sections 1, 4, 6, 7 and 8 shall remain in full force and effect.  No action taken pursuant to this Section shall relieve the Company from liability, if any, in respect of such default.

SECTION 12.         Notices.  All notices and other communications hereunder shall be in writing and shall be deemed to have been duly given if mailed or transmitted by any standard form of telecommunication.  Notices to the Underwriters shall be directed to Merrill Lynch, Pierce, Fenner & Smith Incorporated at 4 World Financial Center, New York, New York 10080, attention of Global Origination Counsel and Goldman, Sachs & Co. at 85 Broad Street, 23rd Floor, New York, New York 10004, attention of Registration Department; and notices to the Company shall be directed to it at 901 Gateway Boulevard, South San Francisco, California 94080, attention of Chief Financial Officer.

SECTION 13.         No Advisory or Fiduciary Relationship.  The Company acknowledges and agrees that (a) the purchase and sale of the Securities pursuant to this Agreement, including the determination of the public offering price of the Securities and any related discounts and commissions, is an arm’s-length commercial transaction between the Company, on the one hand, and the several Underwriters, on the other hand, (b) in connection with the offering contemplated hereby and the process leading to such transaction each Underwriter is and has been acting solely as a principal and is not the agent or fiduciary of the Company, or its stockholders, creditors, employees or any other party, (c) no Underwriter has assumed or will assume an advisory or fiduciary responsibility in favor of the Company with respect to the offering contemplated hereby or the process leading thereto (irrespective of whether such Underwriter has advised or is currently advising the Company on other matters) and no Underwriter has any obligation to the Company with respect to the offering contemplated hereby except the obligations expressly set forth in this Agreement, (d) the Underwriters and their respective affiliates may be engaged in a broad range of transactions that involve interests that differ from those of the Company, and (e) the

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Underwriters have not provided any legal, accounting, regulatory or tax advice with respect to the offering contemplated hereby and the Company has consulted its own legal, accounting, regulatory and tax advisors to the extent it deemed appropriate.

SECTION 14.         Integration.  This Agreement supersedes all prior agreements and understandings (whether written or oral) between the Company and the Underwriters, or any of them, with respect to the subject matter hereof.

SECTION 15.         Parties.  This Agreement shall each inure to the benefit of and be binding upon the Underwriters and the Company and their respective successors.  Nothing expressed or mentioned in this Agreement is intended or shall be construed to give any person, firm or corporation, other than the Underwriters and the Company and their respective successors and the controlling persons and officers and directors referred to in Sections 6 and 7 and their heirs and legal representatives, any legal or equitable right, remedy or claim under or in respect of this Agreement or any provision herein contained.  This Agreement and all conditions and provisions hereof are intended to be for the sole and exclusive benefit of the Underwriters and the Company and their respective successors, and said controlling persons and officers and directors and their heirs and legal representatives, and for the benefit of no other person, firm or corporation.  No purchaser of Securities from any Underwriter shall be deemed to be a successor by reason merely of such purchase.

SECTION 16.         GOVERNING LAW.  THIS AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

SECTION 17.         TIME.  TIME SHALL BE OF THE ESSENCE OF THIS AGREEMENT.  EXCEPT AS OTHERWISE SET FORTH HEREIN, SPECIFIED TIMES OF DAY REFER TO NEW YORK CITY TIME.

SECTION 18.         Counterparts.  This Agreement may be executed in any number of counterparts, each of which shall be deemed to be an original, but all such counterparts shall together constitute one and the same Agreement.

SECTION 19.         Effect of Headings.  The Section headings herein are for convenience only and shall not affect the construction hereof.

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If the foregoing is in accordance with your understanding of our agreement, please sign and return to the Company a counterpart hereof, whereupon this instrument, along with all counterparts, will become a binding agreement among the Underwriters and the Company in accordance with its terms.

	Very truly yours,
	Theravance, Inc.
	By	/s/ Rick E Winningham
		Title: Chief Executive Officer

CONFIRMED AND ACCEPTED,

as of the date first above written:

MERRILL LYNCH & CO.

MERRILL LYNCH, PIERCE, FENNER & SMITH

INCORPORATED

GOLDMAN, SACHS & CO.

By: MERRILL LYNCH, PIERCE, FENNER & SMITH
		INCORPORATED
By	/s/ Saira Ramasastry
Authorized Signatory

For themselves and as Representatives of the other Underwriters named in Schedule A hereto.

By: GOLDMAN, SACHS & CO.
By	/s/ Goldman, Sachs & Co.
Authorized Signatory

For themselves and as Representatives of the other Underwriters named in Schedule A hereto.

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