<SEC-DOCUMENT>0001104659-24-106731.txt : 20241007
<SEC-HEADER>0001104659-24-106731.hdr.sgml : 20241007
<ACCEPTANCE-DATETIME>20241007171801
ACCESSION NUMBER:		0001104659-24-106731
CONFORMED SUBMISSION TYPE:	144
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20241007
DATE AS OF CHANGE:		20241007

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Mersana Therapeutics, Inc.
		CENTRAL INDEX KEY:			0001442836
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		ORGANIZATION NAME:           	03 Life Sciences
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		144
		SEC ACT:		1933 Act
		SEC FILE NUMBER:	001-38129
		FILM NUMBER:		241358610

	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

REPORTING-OWNER:	

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

	FILING VALUES:
		FORM TYPE:		144

	MAIL ADDRESS:	
		STREET 1:		840 MEMORIAL DRIVE
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139
</SEC-HEADER>
<DOCUMENT>
<TYPE>144
<SEQUENCE>1
<FILENAME>primary_doc.xml
<TEXT>
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  <headerData>
    <submissionType>144</submissionType>
    <filerInfo>
      <filer>
        <filerCredentials>
          <!-- Field: Pseudo-Tag; ID: Name; Data: Lowinger Timothy B -->
          <cik>0001709775</cik>
          <ccc>XXXXXXXX</ccc>
        </filerCredentials>
      </filer>
      <liveTestFlag>LIVE</liveTestFlag>


    </filerInfo>
  </headerData>
  <formData>
    <issuerInfo>
      <issuerCik>0001442836</issuerCik>
      <issuerName>Mersana Therapeutics, Inc.</issuerName>
      <secFileNumber>001-38129</secFileNumber>
      <issuerAddress>
        <com:street1>840 Memorial Drive</com:street1>
        <com:city>Cambridge</com:city>
        <com:stateOrCountry>MA</com:stateOrCountry>
        <com:zipCode>02139</com:zipCode>
      </issuerAddress>
      <issuerContactPhone>617-498-0020</issuerContactPhone>
      <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>Timothy B. Lowinger</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
      <relationshipsToIssuer>
        <relationshipToIssuer>Officer</relationshipToIssuer>
      </relationshipsToIssuer>
    </issuerInfo>
    <securitiesInformation>
      <securitiesClassTitle>Common Stock</securitiesClassTitle>
      <brokerOrMarketmakerDetails>
        <name>ETRADE Financial Corporation</name>
        <address>
          <com:street1>3 Edison Drive</com:street1>
          <com:city>Alpharetta</com:city>
          <com:stateOrCountry>GA</com:stateOrCountry>
          <com:zipCode>30005</com:zipCode>
        </address>
      </brokerOrMarketmakerDetails>
      <noOfUnitsSold>8089</noOfUnitsSold>
      <aggregateMarketValue>16339.78</aggregateMarketValue>
      <noOfUnitsOutstanding>122866659</noOfUnitsOutstanding>
      <approxSaleDate>10/02/2024</approxSaleDate>
      <securitiesExchangeName>NASDAQ</securitiesExchangeName>
    </securitiesInformation>
    <securitiesInformation>
      <securitiesClassTitle>Common Stock</securitiesClassTitle>
      <brokerOrMarketmakerDetails>
        <name>ETRADE Financial Corporation</name>
        <address>
          <com:street1>3 Edison Drive</com:street1>
          <com:city>Alpharetta</com:city>
          <com:stateOrCountry>GA</com:stateOrCountry>
          <com:zipCode>30005</com:zipCode>
        </address>
      </brokerOrMarketmakerDetails>
      <noOfUnitsSold>5598</noOfUnitsSold>
      <aggregateMarketValue>11307.96</aggregateMarketValue>
      <noOfUnitsOutstanding>122866659</noOfUnitsOutstanding>
      <approxSaleDate>10/03/2024</approxSaleDate>
      <securitiesExchangeName>NASDAQ</securitiesExchangeName>
    </securitiesInformation>
    <securitiesToBeSold>
      <securitiesClassTitle>Common Stock</securitiesClassTitle>
      <acquiredDate>10/01/2024</acquiredDate>
      <natureOfAcquisitionTransaction>Vesting of restricted stock unit grant</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>50000</amountOfSecuritiesAcquired>
      <paymentDate>10/01/2024</paymentDate>
      <natureOfPayment>Services rendered</natureOfPayment>
    </securitiesToBeSold>
    <nothingToReportFlagOnSecuritiesSoldInPast3Months>Y</nothingToReportFlagOnSecuritiesSoldInPast3Months>
    <remarks>(1) Aggregate market value based on the closing price per share on Nasdaq on October 3, 2024. (2) Shares outstanding as of October 3, 2024.</remarks>
    <noticeSignature>
      <noticeDate>10/07/2024</noticeDate>
      <planAdoptionDates>
        <planAdoptionDate>05/10/2023</planAdoptionDate>
      </planAdoptionDates>
      <signature>/s/ Alejandra Carvajal, as attorney-in-fact for Timothy B. Lowinger</signature>
    </noticeSignature>
  </formData>
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</SEC-DOCUMENT>
