<SEC-DOCUMENT>0001104659-21-027549.txt : 20210224
<SEC-HEADER>0001104659-21-027549.hdr.sgml : 20210224
<ACCEPTANCE-DATETIME>20210224170050
ACCESSION NUMBER:		0001104659-21-027549
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210222
FILED AS OF DATE:		20210224
DATE AS OF CHANGE:		20210224

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Lowinger Timothy B
		CENTRAL INDEX KEY:			0001709775

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38129
		FILM NUMBER:		21674531

	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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    <footnotes>
        <footnote id="F1">Transaction effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on August 12, 2020.</footnote>
        <footnote id="F2">This price is a weighted average price. These shares were sold in multiple transactions at prices ranging from $19.82 to $20.43, inclusive. The reporting person undertakes to provide to Mersana Therapeutics, Inc., any other 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 this footnote.</footnote>
        <footnote id="F3">The option vests in equal quarterly installments over the first four years after the vesting commencement date, January 23, 2019.</footnote>
        <footnote id="F4">The option vests in equal quarterly installments over the first four years after the vesting commencement date, January 15, 2020.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Brian DeSchuytner, as Attorney-in-Fact</signatureName>
        <signatureDate>2021-02-24</signatureDate>
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