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* Sonsini Peter W. (Last) (First) (Middle) 2855 SAND HILL ROAD (Street) MENLO PARK CA 94025 (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) 04/09/2020
	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	04/09/2020		J(1)		4,000,000	D	$0.00	7,959,520	I	See Note 2(2)
Common Stock	04/09/2020		J(3)		40,000	A	$0.00	40,000	I	See Note 4(4)
Common Stock	04/09/2020		J(5)		40,000	D	$0.00	0	I	See Note 4(4)
Common Stock	04/09/2020		J(6)		20,000	A	$0.00	20,000	I	See Note 7(7)
Common Stock	04/09/2020		J(8)		20,000	D	$0.00	0	I	See Note 7(7)
Common Stock	04/09/2020		J(9)		1,146	A	$0.00	1,146	I	See Note 10(10)
Common Stock	04/09/2020		J(11)		497	A	$0.00	497	D

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

Explanation of Responses:

1. New Enterprise Associates 14, L.P. ("NEA 14") made a pro rata distribution for no consideration of an aggregate of 4,000,000 shares of Common Stock of the Issuer to its general partner and its limited partners on April 9, 2020.

2. The Reporting Person is a director of NEA 14 GP, LTD ("NEA 14 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 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.

3. NEA Partners 14 received 40,000 shares of Common Stock of the Issuer in the distribution by NEA 14 on April 9, 2020.

4. The Reporting Person is a director of NEA 14 LTD, which is the sole general partner of NEA Partners 14, 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 Partners 14 shares in which the Reporting Person has no pecuniary interest.

5. NEA Partners 14 made a pro rata distribution for no consideration of an aggregate of 40,000 shares of Common Stock of the Issuer to its limited partners on April 9, 2020.

6. NEA 14 Manager Fund, L.P. ("NEA 14 Manager Fund") received 20,000 shares of Common Stock of the Issuer in the distribution by NEA 14 on April 9, 2020.

7. The Reporting Person is a director of NEA 14 LTD, which is the sole general partner of NEA 14 Manager Fund. 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 securities of the Issuer held by NEA 14 Manager Fund in which the Reporting Person has no pecuniary interest.

8. NEA 14 Manager Fund made a pro rata distribution for no consideration of an aggregate of 20,000 shares of Common Stock of the Issuer to its limited partners on April 9, 2020.

9. Peter W. Sonsini and Diane C. Sonsini as Trustees of the Peter & Diane Sonsini Family Trust dated January 17, 2007 (the "Sonsini Trust") received 1,146 shares of Common Stock of the Issuer in the distribution by NEA Partners 14 on April 9, 2020.

10. The securities are held directly by the Sonsini Trust. The Reporting Person disclaims beneficial ownership within the meaning of Section 16 of the 1934 Act, as amended, of such portion of the shares of Common Stock of the Issuer held by the Sonsini Trust in which the Reporting Person has no pecuniary interest.

11. The Reporting Person received 497 shares of Common Stock of the Issuer in the distribution by NEA 14 Manager Fund on April 9, 2020.

Remarks:

	/s/ Sasha Keough, Attorney-in-Fact	04/13/2020
	** 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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.