Martin H. Huber Jr. - 11 Sep 2023 Form 4 Insider Report for Mersana Therapeutics, Inc. (MRSN)

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	+1,000,000		$0.000000	1,000,000	11 Sep 2023	Common Stock	1,000,000	$1.32	Direct	F1
transaction	MRSN	Restricted stock unit	Award	$0	+667,000		$0.000000	667,000	11 Sep 2023	Common Stock	667,000		Direct	F2, F3

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

Id	Content
F1	25% of the shares subject to the option will vest on the first anniversary of the grant, and the remainder shall vest in 12 equal quarterly installments thereafter, subject to the Reporting Person's continuous service to the Issuer through each such vesting date.
F2	Each restricted stock unit ("RSU") represents the contingent right to receive one share of Common Stock of the Issuer.
F3	The RSUs shall vest in equal annual installments over four years from the date of grant, subject to the Reporting Person's continuous service to the Issuer through each such vesting date.