<SEC-DOCUMENT>0001104659-21-081609-index.html : 20210615
<SEC-HEADER>0001104659-21-081609.hdr.sgml : 20210615
<ACCEPTANCE-DATETIME>20210615180320
ACCESSION NUMBER:		0001104659-21-081609
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210611
FILED AS OF DATE:		20210615
DATE AS OF CHANGE:		20210615

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Dere Willard H
		CENTRAL INDEX KEY:			0001311569

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38129
		FILM NUMBER:		211019917

	MAIL ADDRESS:	
		STREET 1:		ONE AMGEN CENTER DRIVE
		CITY:			THOUSAND OAKS
		STATE:			CA
		ZIP:			91320-1799

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>tm2119714-4_4seq1.xml
<DESCRIPTION>OWNERSHIP DOCUMENT
<TEXT>
Document 1 - file: tm2119714-4_4seq1.html

Document 1 - RAW XML: tm2119714-4_4seq1.xml

</DOCUMENT>
</SEC-DOCUMENT>