<SEC-DOCUMENT>0000315066-17-002493-index.html : 20170627
<SEC-HEADER>0000315066-17-002493.hdr.sgml : 20170627
<ACCEPTANCE-DATETIME>20170627210132
ACCESSION NUMBER:		0000315066-17-002493
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20170627
FILED AS OF DATE:		20170627
DATE AS OF CHANGE:		20170627

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

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			FMR LLC
		CENTRAL INDEX KEY:			0000315066
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38129
		FILM NUMBER:		17933593

	BUSINESS ADDRESS:	
		STREET 1:		245 SUMMER STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02210
		BUSINESS PHONE:		6175706339

	MAIL ADDRESS:	
		STREET 1:		245 SUMMER STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02210

	FORMER NAME:	
		FORMER CONFORMED NAME:	FMR CORP
		DATE OF NAME CHANGE:	19920717
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
Document 1 - file: primary_doc.html

Document 1 - RAW XML: primary_doc.xml

</DOCUMENT>
</SEC-DOCUMENT>