Mersana Therapeutics, Inc. — Director's Dealing 2017

Jun 28, 2017

SEC Form 3 — Initial Statement of Beneficial Ownership

Issuer: Mersana Therapeutics, Inc. (MRSN)
CIK: 0001442836
Period of Report: 2017-06-27

Reporting Person: FMR LLC (10% Owner, See Remark 1)

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	383357	Indirect
Common Stock	2597	Indirect

Holdings (Derivative)

Security	Exercise Price	Expiration	Underlying	Shares	Ownership
Warrant	$0.05	2023-09-27	Common Stock (19126)		Indirect
Series A-1 Convertible Preferred Stock	$		Common Stock (718375)		Indirect
Series B-1 Convertible Preferred Stock	$		Common Stock (611606)		Indirect

Footnotes

F1: The Series A-1 and B-1 Convertible Preferred Stock are convertible on a one-for-one basis into the number of shares of Common Stock as shown in column 3 at any time at the holder's election, and automatically upon the closing of the Issuer's initial public offering, and have no expiration date.