Editas Medicine, Inc. — Director's Dealing 2016

Feb 2, 2016

SEC Form 3 — Initial Statement of Beneficial Ownership

Issuer: Editas Medicine, Inc. (EDIT)
CIK: 0001650664
Period of Report: 2016-02-02

Reporting Person: Third Rock Ventures III, L.P. (10% Owner)
Reporting Person: Third Rock Ventures GP III, L.P. (10% Owner)
Reporting Person: TRV GP III, LLC (10% Owner)
Reporting Person: LEVIN MARK J (10% Owner)
Reporting Person: STARR KEVIN P (10% Owner)
Reporting Person: TEPPER ROBERT I (10% Owner)

Holdings (Derivative)

Security	Exercise Price	Expiration	Underlying	Shares	Ownership
Series A-1 Preferred Stock	$		Common Stock (2549437)		Direct
Series A-2 Preferred Stock	$		Common Stock (2021269)		Direct
Series B Preferred Stock	$		Common Stock (85470)		Direct

Footnotes

F1: Each share of Series A-1, Series A-2 and Series B Preferred Stock is convertible, at any time, at the holder's election, into Common Stock of the Issuer on a 2.6-for-one basis. In addition, effective upon the closing of the Issuer's initial public offering of its Common Stock, each share of preferred stock will automatically convert on a 2.6-for-one basis without payment of consideration. The preferred stock has no expiration date.

F2: The shares are directly held by Third Rock Ventures III, L.P. ("TRV III"). The general partner of TRV III is Third Rock Ventures GP III, L.P. ("TRV GP III"). The general partner of TRV GP III is TRV GP III, LLC ("TRV GP III LLC"). The individual managers of TRV GP III LLC are Mark Levin ("Levin"), Kevin Starr ("Starr") and Dr. Robert Tepper ("Tepper"). Each of TRV GP III, TRV GP III LLC, Levin, Starr and Tepper disclaims beneficial ownership of these shares except to the extent of its or his pecuniary interest therein, if any.