<SEC-DOCUMENT>0000899243-21-047829.txt : 20211210
<SEC-HEADER>0000899243-21-047829.hdr.sgml : 20211210
<ACCEPTANCE-DATETIME>20211210203342
ACCESSION NUMBER:		0000899243-21-047829
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		2
CONFORMED PERIOD OF REPORT:	20211208
FILED AS OF DATE:		20211210
DATE AS OF CHANGE:		20211210

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BCIP Life Sciences Associates, LP
		CENTRAL INDEX KEY:			0001702921
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-40925
		FILM NUMBER:		211486729

	BUSINESS ADDRESS:	
		STREET 1:		200 CLARENDON STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		6175162878

	MAIL ADDRESS:	
		STREET 1:		200 CLARENDON STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Bain Capital Life Sciences Investors, LLC
		CENTRAL INDEX KEY:			0001703031
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-40925
		FILM NUMBER:		211486734

	BUSINESS ADDRESS:	
		STREET 1:		200 CLARENDON STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		6175162878

	MAIL ADDRESS:	
		STREET 1:		200 CLARENDON STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Bain Capital Life Sciences Fund II, L.P.
		CENTRAL INDEX KEY:			0001773187
		STATE OF INCORPORATION:			E9
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-40925
		FILM NUMBER:		211486733

	BUSINESS ADDRESS:	
		STREET 1:		200 CLARENDON STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		6175162000

	MAIL ADDRESS:	
		STREET 1:		200 CLARENDON STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Bain Capital Life Sciences Investors II, LLC
		CENTRAL INDEX KEY:			0001796155
		STATE OF INCORPORATION:			E9
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-40925
		FILM NUMBER:		211486732

	BUSINESS ADDRESS:	
		STREET 1:		200 CLARENDON STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		617-516-2000

	MAIL ADDRESS:	
		STREET 1:		200 CLARENDON STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BCLS II Investco, LP
		CENTRAL INDEX KEY:			0001818893
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-40925
		FILM NUMBER:		211486731

	BUSINESS ADDRESS:	
		STREET 1:		200 CLARENDON STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		6175162878

	MAIL ADDRESS:	
		STREET 1:		200 CLARENDON STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BCLS II Investo (GP), LLC
		CENTRAL INDEX KEY:			0001819101
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-40925
		FILM NUMBER:		211486730

	BUSINESS ADDRESS:	
		STREET 1:		200 CLARENDON STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		6175162878

	MAIL ADDRESS:	
		STREET 1:		200 CLARENDON STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Xilio Therapeutics, Inc.
		CENTRAL INDEX KEY:			0001840233
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				851623397
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		828 WINTER STREET
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02451
		BUSINESS PHONE:		617-833-1027

	MAIL ADDRESS:	
		STREET 1:		828 WINTER STREET
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02451
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<DESCRIPTION>FORM 4 SUBMISSION
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    <periodOfReport>2021-12-08</periodOfReport>

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    <issuer>
        <issuerCik>0001840233</issuerCik>
        <issuerName>Xilio Therapeutics, Inc.</issuerName>
        <issuerTradingSymbol>XLO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001703031</rptOwnerCik>
            <rptOwnerName>Bain Capital Life Sciences Investors, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>200 CLARENDON STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
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    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001773187</rptOwnerCik>
            <rptOwnerName>Bain Capital Life Sciences Fund II, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>200 CLARENDON STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001796155</rptOwnerCik>
            <rptOwnerName>Bain Capital Life Sciences Investors II, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>200 CLARENDON STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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        <reportingOwnerRelationship>
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            <isOfficer>0</isOfficer>
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            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001818893</rptOwnerCik>
            <rptOwnerName>BCLS II Investco, LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>200 CLARENDON STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001819101</rptOwnerCik>
            <rptOwnerName>BCLS II Investo (GP), LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>200 CLARENDON STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001702921</rptOwnerCik>
            <rptOwnerName>BCIP Life Sciences Associates, LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>200 CLARENDON STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-12-08</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>13458</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>9.6206</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2776402</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                    <footnoteId id="F6"/>
                    <footnoteId id="F7"/>
                    <footnoteId id="F8"/>
                    <footnoteId id="F9"/>
                    <footnoteId id="F10"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-12-09</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4011</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>9.8442</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2780413</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                    <footnoteId id="F6"/>
                    <footnoteId id="F7"/>
                    <footnoteId id="F8"/>
                    <footnoteId id="F9"/>
                    <footnoteId id="F10"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-12-10</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>21812</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>9.5619</value>
                    <footnoteId id="F4"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2802225</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                    <footnoteId id="F6"/>
                    <footnoteId id="F7"/>
                    <footnoteId id="F8"/>
                    <footnoteId id="F9"/>
                    <footnoteId id="F10"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
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            <transactionDate>
                <value>2021-12-10</value>
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            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>3188</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>10.2378</value>
                    <footnoteId id="F5"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
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            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2805413</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                    <footnoteId id="F6"/>
                    <footnoteId id="F7"/>
                    <footnoteId id="F8"/>
                    <footnoteId id="F9"/>
                    <footnoteId id="F10"/>
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    <footnotes>
        <footnote id="F1">On December 8, 2021, December 9, 2021 and December 10, 2021, BCLS II Investco, LP (&quot;BCLS II Investco&quot;) purchased 13,458, 4,011 and 25,000 shares of the Issuer's common stock, respectively.</footnote>
        <footnote id="F2">The price reported in Column 4 is a weighted average price. The shares were purchased in multiple transactions at prices ranging from $9.41 to $9.75, inclusive. The reporting persons undertake to provide to the Issuer, any securityholder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the ranges set forth in footnotes (2) through (5) to this Form 4.</footnote>
        <footnote id="F3">The price reported in Column 4 is a weighted average price. The shares were purchased in multiple transactions at prices ranging from $9.53 to $10.00, inclusive.</footnote>
        <footnote id="F4">The price reported in Column 4 is a weighted average price. The shares were purchased in multiple transactions at prices ranging from $9.07 to $10.00, inclusive.</footnote>
        <footnote id="F5">The price reported in Column 4 is a weighted average price. The shares were purchased in multiple transactions at prices ranging from $10.13 to $10.25, inclusive.</footnote>
        <footnote id="F6">Represents shares of the Issuer's common stock held by Bain Capital Life Sciences Fund II, L.P. (&quot;BCLS II&quot;), BCLS II Investco and BCIP Life Sciences Associates, LP (&quot;BCIPLS&quot; and, together with BCLS II and BCLS II Investco, the &quot;Bain Capital Life Sciences Entities&quot;). Following the completion of the transactions reported in footnote (1) to this Form 4, BCLS II, BCLS II Investco and BCIPLS each holds 1,348,682, 1,292,469 and 164,262 shares of the Issuer's common stock, respectively.</footnote>
        <footnote id="F7">Bain Capital Life Sciences Investors II, LLC (&quot;BCLSI II&quot;) is the general partner of BCLS II. As a result, BCLSI II may be deemed to share voting and dispositive power with respect to the securities held by BCLS II. BCLSI II disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.</footnote>
        <footnote id="F8">BCLS II Investco (GP), LLC (&quot;BCLS II Investco GP&quot;), whose manager is BCLS II, is the general partner of BCLS II Investco. As a result, each of BCLSI II, BCLS II and BCLS II Investco GP may be deemed to share voting and dispositive power with respect to the securities held by BCLS II Investco. Each of BCLSI II, BCLS II and BCLS II Investco GP disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.</footnote>
        <footnote id="F9">Boylston Coinvestors, LLC is the general partner of BCIPLS.</footnote>
        <footnote id="F10">Bain Capital Life Sciences Investors, LLC (&quot;BCLSI&quot;) is the manager of BCLSI II and governs the investment strategy and decision-making process with respect to investments held by BCIPLS. As a result, BCLSI may be deemed to share voting and dispositive power with respect to the securities held by the Bain Capital Life Sciences Entities. BCLSI disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.</footnote>
    </footnotes>

    <remarks>Exhibit 99.1: Joint Filer Information</remarks>

    <ownerSignature>
        <signatureName>See Signatures Included in Exhibit 99.1</signatureName>
        <signatureDate>2021-12-10</signatureDate>
    </ownerSignature>
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<PRE>
                                                                Exhibit 99.1

                    List of Joint Filers and Signature Page

BAIN CAPITAL LIFE SCIENCES INVESTORS, LLC

By: /s/ Andrew Hack
    ---------------
Title: Managing Director


BAIN CAPITAL LIFE SCIENCES FUND II, L.P.

By: Bain Capital Life Sciences Investors II, LLC,
its general partner

By: Bain Capital Life Sciences Investors, LLC,
its manager

By: /s/ Andrew Hack
    ---------------
Title: Managing Director


BAIN CAPITAL LIFE SCIENCES INVESTORS II, LLC

By: Bain Capital Life Sciences Investors, LLC,
its manager

By: /s/ Andrew Hack
    ---------------
Title: Managing Director


BCLS II INVESTCO, LP

By: BCLS II Investco (GP), LLC,
its general partner

By: Bain Capital Life Sciences Fund II, L.P.,
its manager

By: Bain Capital Life Sciences Investors II, LLC,
its general partner

By: Bain Capital Life Sciences Investors, LLC,
its manager

By: /s/ Andrew Hack
    ---------------
Title: Managing Director


BCLS II INVESTCO (GP), LLC

By: Bain Capital Life Sciences Fund II, L.P.,
its manager

By: Bain Capital Life Sciences Investors II, LLC,
its general partner

By: Bain Capital Life Sciences Investors, LLC,
its manager

By: /s/ Andrew Hack
    ---------------
Title: Managing Director


BCIP LIFE SCIENCES ASSOCIATES, LP

By: Boylston Coinvestors, LLC,
its general partner

By: /s/ Andrew Hack
    ---------------
Title: Authorized Signatory

</PRE>
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