<SEC-DOCUMENT>0001273087-22-000017-index.html : 20220217
<SEC-HEADER>0001273087-22-000017.hdr.sgml : 20220217
<ACCEPTANCE-DATETIME>20220217161239
ACCESSION NUMBER:		0001273087-22-000017
CONFORMED SUBMISSION TYPE:	SC 13G
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20220217
DATE AS OF CHANGE:		20220217
GROUP MEMBERS:		ISRAEL A. ENGLANDER
GROUP MEMBERS:		MILLENNIUM GROUP MANAGEMENT LLC
GROUP MEMBERS:		MILLENNIUM MANAGEMENT LLC

SUBJECT COMPANY:	

	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

	FILING VALUES:
		FORM TYPE:		SC 13G
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-90033
		FILM NUMBER:		22648213

	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

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MILLENNIUM MANAGEMENT LLC
		CENTRAL INDEX KEY:			0001273087
		IRS NUMBER:				133804139
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13G

	BUSINESS ADDRESS:	
		STREET 1:		399 PARK AVENUE
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022
		BUSINESS PHONE:		(212) 841-4100

	MAIL ADDRESS:	
		STREET 1:		399 PARK AVENUE
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	MILLENNIUM MANAGEMENT, L.L.C.
		DATE OF NAME CHANGE:	20050310

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	MILLENNIUM MANAGEMENT LLC
		DATE OF NAME CHANGE:	20031212
</SEC-HEADER>
<DOCUMENT>
<TYPE>SC 13G
<SEQUENCE>1
<FILENAME>MRSN_SC13G.htm
<TEXT>
Document 1 - file: MRSN_SC13G.htm

</DOCUMENT>
</SEC-DOCUMENT>