<SEC-DOCUMENT>0001104659-22-005555.txt : 20220119
<SEC-HEADER>0001104659-22-005555.hdr.sgml : 20220119
<ACCEPTANCE-DATETIME>20220119181922
ACCESSION NUMBER:		0001104659-22-005555
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20220114
FILED AS OF DATE:		20220119
DATE AS OF CHANGE:		20220119

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Mandelia Ashish
		CENTRAL INDEX KEY:			0001782805

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38129
		FILM NUMBER:		22540005

	MAIL ADDRESS:	
		STREET 1:		840 MEMORIAL DRIVE
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Mersana Therapeutics, Inc.
		CENTRAL INDEX KEY:			0001442836
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		840 MEMORIAL DRIVE
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139
		BUSINESS PHONE:		617-498-0020

	MAIL ADDRESS:	
		STREET 1:		840 MEMORIAL DRIVE
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	MERSANA THERAPEUTICS INC
		DATE OF NAME CHANGE:	20080813
</SEC-HEADER>
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        <issuerName>Mersana Therapeutics, Inc.</issuerName>
        <issuerTradingSymbol>MRSN</issuerTradingSymbol>
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            <rptOwnerName>Mandelia Ashish</rptOwnerName>
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            <rptOwnerState>MA</rptOwnerState>
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            <otherText></otherText>
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                </transactionAcquiredDisposedCode>
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    <footnotes>
        <footnote id="F1">Each restricted stock unit (&quot;RSU&quot;) represents a contingent right to receive one share of the Issuer's common stock upon vesting.</footnote>
        <footnote id="F2">Represents the number of shares sold by the reporting person to cover tax withholding obligations in connection with the vesting of the RSUs listed in Table II. These sales were mandated by the Issuer's election under its equity incentive plans to require the reporting person to sell a number of shares of common stock needed to satisfy his tax withholding obligations and does not represent a discretionary trade by the reporting person.</footnote>
        <footnote id="F3">The price reported in Column 4 is a weighted-average price. These shares were sold in multiple transactions at prices ranging from $5.83 to $5.92, inclusive. The reporting person undertakes to provide to Mersana Therapeutics, Inc., any security holder of Mersana Therapeutics, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnote (3) to this Form 4.</footnote>
        <footnote id="F4">50% of the total number of RSUs vested as of January 14, 2022, and thereafter shall vest in equal annual installments over the next two years.</footnote>
        <footnote id="F5">25% of the total number of RSUs vested on January 14, 2022, and thereafter shall vest in equal annual installments over the next three years.</footnote>
        <footnote id="F6">The option vests in equal quarterly installments over the first four years after the vesting commencement date, January 14, 2022.</footnote>
        <footnote id="F7">The restricted stock units vest in equal annual installments over the first four years after the vesting commencement date, January 14, 2022.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Brian DeSchuytner, as Attorney-in-Fact</signatureName>
        <signatureDate>2022-01-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
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</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
