SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* Florence Anthony A. Jr. (Last) (First) (Middle) 5425 WISCONSIN AVENUE SUITE 800 (Street) CHEVY CHASE MD 20815 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol Mersana Therapeutics, Inc. [ MRSN ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 07/03/2017
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) X Form filed by One Reporting Person Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	07/03/2017		C		7,140,138(1)	A	(2)	7,140,138	I	See Note 3(3)
Common Stock	07/03/2017		P		1,000,000	A	$15	8,140,138	I	See Note 3(3)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Series A-1 Preferred Stock	(2)	07/03/2017		C			11,931,173	(2)	(2)	Common Stock	2,647,241	$0.00	0	I	See Note 3(3)
Series B-1 Preferred Stock	(2)	07/03/2017		C			18,001,419	(2)	(2)	Common Stock	4,000,314	$0.00	0	I	See Note 3(3)
Series C-1 Preferred Stock	(2)	07/03/2017		C			2,216,626	(2)	(2)	Common Stock	492,583	$0.00	0	I	See Note 3(3)

Explanation of Responses:

1. The total represents shares received upon conversion of Series A-1, Series B-1 and Series C-1 Convertible Preferred Stock.

2. Upon closing of the Issuer's initial public offering, each share of Series A-1, Series B-1 and Series C-1 Convertible Preferred Stock automatically converted into .22222 shares of Common Stock without payment of further consideration. There was no expiration date for the Series A-1, Series B-1 or Series C-1 Convertible Preferred Stock.

3. The Reporting Person is a director of NEA 14 GP, LTD, which is the sole general partner of NEA Partners 14, L.P. ("NEA Partners 14"). NEA Partners 14 is the sole general partner of New Enterprise Associates 14, L.P. ("NEA 14"), which is the direct beneficial owner of the securities. The Reporting Person disclaims beneficial ownership, within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the NEA 14 shares in which the Reporting Person has no pecuniary interest.

Remarks:

	/s/ Sasha Keough, attorney-in-fact	07/06/2017
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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