DAVID M. MOTT - 12 Jun 2025 Form 4 Insider Report for Mersana Therapeutics, Inc. (MRSN)

Role: Director
Signature: /s/ Alejandra Carvajal, Attorney-in-Fact
Issuer symbol: MRSN
Transactions as of: 12 Jun 2025
Net transactions value: $0
Form type: 4
Filing time: 13 Jun 2025, 16:55:20 UTC
Previous filing: 11 Jun 2025
Next filing: 18 Jun 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
MOTT DAVID M	Director	C/O MERSANA THERAPEUTICS, INC., 840 MEMORIAL DRIVE, CAMBRIDGE	/s/ Alejandra Carvajal, Attorney-in-Fact	13 Jun 2025	0001219871

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	MRSN	Stock Option (right to buy)	Award	$0	+61,500		$0.000000	61,500	12 Jun 2025	Common Stock	61,500	$0.3600	Direct	F1

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	The award will vest in full on the earlier of the first anniversary of the date of grant or the date of the 2026 Annual Meeting of Stockholders of the Issuer, subject to the Reporting Person's continuous service with the Issuer on such vesting date.