<SEC-DOCUMENT>0001104659-21-005950-index.html : 20210120
<SEC-HEADER>0001104659-21-005950.hdr.sgml : 20210120
<ACCEPTANCE-DATETIME>20210120190440
ACCESSION NUMBER:		0001104659-21-005950
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:			Kaufman Michael J.
		CENTRAL INDEX KEY:			0001709996

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38129
		FILM NUMBER:		21539996

	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>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>tm211948-10_4seq1.xml
<DESCRIPTION>OWNERSHIP DOCUMENT
<TEXT>
Document 1 - file: tm211948-10_4seq1.html

Document 1 - RAW XML: tm211948-10_4seq1.xml

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-24
<SEQUENCE>2
<FILENAME>tm211948-10_ex24.htm
<DESCRIPTION>EXHIBIT 24
<TEXT>
Document 2 - file: tm211948-10_ex24.htm

</DOCUMENT>
</SEC-DOCUMENT>