<SEC-DOCUMENT>0001104659-21-005943.txt : 20210120
<SEC-HEADER>0001104659-21-005943.hdr.sgml : 20210120
<ACCEPTANCE-DATETIME>20210120190211
ACCESSION NUMBER:		0001104659-21-005943
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		2
CONFORMED PERIOD OF REPORT:	20210115
FILED AS OF DATE:		20210120
DATE AS OF CHANGE:		20210120

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Hege Kristen
		CENTRAL INDEX KEY:			0001299171

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38129
		FILM NUMBER:		21539978

	MAIL ADDRESS:	
		STREET 1:		500 FORBES BLVD
		CITY:			SOUTH SAN FRANCISCO
		STATE:			CA
		ZIP:			94070

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>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>tm211948-3_4seq1.xml
<DESCRIPTION>OWNERSHIP DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-01-15</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001442836</issuerCik>
        <issuerName>Mersana Therapeutics, Inc.</issuerName>
        <issuerTradingSymbol>MRSN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001299171</rptOwnerCik>
            <rptOwnerName>Hege Kristen</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MERSANA THERAPEUTICS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>840 MEMORIAL DRIVE</rptOwnerStreet2>
            <rptOwnerCity>CAMBRIDGE</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02139</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>21.09</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2021-01-15</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2547</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2031-01-15</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2547</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2547</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The option becomes exercisable in equal quarterly installments on the last day of each calendar quarter of 2021.</footnote>
    </footnotes>

    <remarks>Exhibit List: Exhibit 24 - Power of Attorney</remarks>

    <ownerSignature>
        <signatureName>/s/ Brian DeSchuytner, as Attorney-in-Fact</signatureName>
        <signatureDate>2021-01-20</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-24
<SEQUENCE>2
<FILENAME>tm211948d3_ex24.htm
<DESCRIPTION>POWER OF ATTORNEY
<TEXT>
<HTML>
<HEAD>
     <TITLE></TITLE>
</HEAD>
<BODY STYLE="font: 10pt Times New Roman, Times, Serif">

<P STYLE="text-align: right; margin: 0"><B>Exhibit 24</B></P>

<P STYLE="margin: 0">&nbsp;</P>

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">POWER OF ATTORNEY</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify; text-indent: 0.5in">The undersigned hereby
constitutes and appoints Anna Protopapas, Brian DeSchuytner, and Jonathan Owen, with full power of substitution, as the undersigned&rsquo;s
true and lawful attorney-in-fact to:</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify; text-indent: 0.5in">&nbsp;</P>

<TABLE CELLPADDING="0" CELLSPACING="0" WIDTH="100%" STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0.5in"></TD><TD STYLE="width: 0.5in">(1)</TD><TD STYLE="text-align: justify">prepare, execute in the undersigned&rsquo;s name and on the undersigned&rsquo;s behalf, and submit
to the U.S. Securities and Exchange Commission (the &ldquo;SEC&rdquo;) a Form ID, including amendments thereto, and any other documents
necessary or appropriate to obtain codes and passwords enabling the undersigned to make electronic filings with the SEC of reports
required by Section 16(a) of the Securities Exchange Act of 1934, as amended, or any rule or regulation of the SEC;</TD></TR></TABLE>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 1in; text-align: justify; text-indent: -0.5in">&nbsp;</P>

<TABLE CELLPADDING="0" CELLSPACING="0" WIDTH="100%" STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0.5in"></TD><TD STYLE="width: 0.5in">(2)</TD><TD STYLE="text-align: justify">execute for and on behalf of the undersigned, in the undersigned&rsquo;s capacity as officer and/or
director of Mersana Therapeutics, Inc. (the &ldquo;Company&rdquo;), Forms 3, 4, and 5 in accordance with Section 16(a) of the Securities
Exchange Act of 1934, as amended, and the rules thereunder;</TD></TR></TABLE>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 1in; text-align: justify; text-indent: -0.5in">&nbsp;</P>

<TABLE CELLPADDING="0" CELLSPACING="0" WIDTH="100%" STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0.5in"></TD><TD STYLE="width: 0.5in">(3)</TD><TD STYLE="text-align: justify">do and perform any and all acts for and on behalf of the undersigned that may be necessary or desirable
to complete and execute any such Form 3, 4, or 5, complete and execute any amendment or amendments thereto, and timely file such
form with the SEC and any stock exchange or similar authority; and</TD></TR></TABLE>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 1in; text-align: justify; text-indent: -0.5in">&nbsp;</P>

<TABLE CELLPADDING="0" CELLSPACING="0" WIDTH="100%" STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0.5in"></TD><TD STYLE="width: 0.5in">(4)</TD><TD STYLE="text-align: justify">take any other action of any type whatsoever in connection with the foregoing that, in the opinion of such attorney-in-fact, may be of
benefit to, in the best interest of, or legally required by, the undersigned, it being understood that the documents executed by such
attorney-in-fact on behalf of the undersigned pursuant to this Power of Attorney shall be in such form and shall contain such terms and
conditions as such attorney-in-fact may approve in such attorney-in-fact&rsquo;s discretion.</TD></TR></TABLE>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify; text-indent: 0.5in">The undersigned hereby grants to such attorney-in-fact full power and authority to do and perform any and every act and thing whatsoever
requisite, necessary, or proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and
purposes as the undersigned might or could do if personally present, with full power of substitution or revocation, hereby ratifying and
confirming all that such attorney-in-fact, or such attorney-in-fact&rsquo;s substitute or substitutes, shall lawfully do or cause to be
done by virtue of this power of attorney and the rights and powers herein granted. The undersigned acknowledges that the foregoing attorneys-in-fact,
in serving in such capacity at the request of the undersigned, are not assuming, nor is the Company assuming, any of the undersigned&rsquo;s
responsibilities to comply with Section 16 of the Securities Exchange Act of 1934, as amended.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify; text-indent: 0.5in">This Power of Attorney
shall remain in full force and effect until the undersigned is no longer required to file Forms 3, 4, and 5 with respect to the
undersigned&rsquo;s holdings of and transactions in securities issued by the Company, unless earlier revoked by the undersigned
in a signed writing delivered to the foregoing attorney-in-fact.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; text-indent: 0.5in">[<I>Remainder of page intentionally left blank</I>]</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; text-indent: 0.5in"></P>

<!-- Field: Page; Sequence: 1 -->
    <DIV STYLE="margin-top: 12pt; margin-bottom: 6pt; border-bottom: Black 1pt solid"><P STYLE="margin: 0pt">&nbsp;</P></DIV>
    <DIV STYLE="break-before: page; margin-top: 6pt; margin-bottom: 12pt"><P STYLE="margin: 0pt">&nbsp;</P></DIV>
    <!-- Field: /Page -->

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify; text-indent: 0.5in">IN WITNESS WHEREOF,
the undersigned has caused this Power of Attorney to be executed as of this 9th day of October, 2020.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify; text-indent: 0.5in">&nbsp;</P>

<TABLE CELLPADDING="0" CELLSPACING="0" STYLE="font-size: 10pt; border-collapse: collapse; width: 100%">
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD STYLE="font-size: 10pt; width: 50%">&nbsp;</TD>
    <TD STYLE="border-bottom: Black 1pt solid; width: 50%; font: 10pt Times New Roman, Times, Serif">/s/ Kristen Hege</TD></TR>
<TR STYLE="font-size: 10pt; vertical-align: bottom">
    <TD STYLE="font-size: 10pt">&nbsp;</TD>
    <TD STYLE="font: 10pt Times New Roman, Times, Serif">Kristen Hege, M.D.</TD></TR>
</TABLE>


<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt; text-align: center">[Signature Page to Limited Power of Attorney]</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"></P>

<!-- Field: Page; Sequence: 2; Options: Last -->
    <DIV STYLE="margin-top: 12pt; margin-bottom: 6pt; border-bottom: Black 1pt solid"><P STYLE="margin: 0pt">&nbsp;</P></DIV>
    <!-- Field: /Page -->

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

</BODY>
</HTML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
