Editas Medicine, Inc. — Director's Dealing 2016

Feb 8, 2016

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Editas Medicine, Inc. (EDIT)
CIK: 0001650664
Period of Report: 2016-02-08

Reporting Person: Flynn James E (10% Owner, Possible Member of 10% Group)
Reporting Person: Deerfield Mgmt III, L.P. (10% Owner, Possible Member of 10% Group)
Reporting Person: DEERFIELD MANAGEMENT CO (10% Owner, Possible Member of 10% Group)
Reporting Person: Deerfield Private Design Fund III, L.P. (10% Owner, Possible Member of 10% Group)
Reporting Person: Deerfield Healthcare Innovations Fund, L.P. (10% Owner, Possible Member of 10% Group)
Reporting Person: Deerfield Mgmt HIF, L.P. (10% Owner, Possible Member of 10% Group)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2016-02-08	Common Stock	C	854700	—	Acquired	854700	Indirect
2016-02-08	Common Stock	C	854700	—	Acquired	854700	Indirect
2016-02-08	Common Stock	P	100000	$16.00	Acquired	954700	Indirect

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2016-02-08	Series B Preferred Stock	$	C	854700	Disposed		Common Stock (854700)	Indirect
2016-02-08	Series B Preferred Stock	$	C	854700	Disposed		Common Stock (854700)	Indirect

Footnotes

F1: Each share of Series B Preferred Stock automatically converted into 1 share of the Issuer's Common Stock upon the closing of the Issuer's initial public offering of Common Stock.

F2: This Form 4 is being filed by the undersigned as well as the entities listed on the Joint Filer Information Statement attached as an exhibit hereto (the "Reporting Persons"). Deerfield Mgmt III, L.P. is the general partner of Deerfield Private Design Fund III, L.P. ("Fund III") and Deerfield Mgmt HIF, L.P. is the general partner of Deerfield Healthcare Innovations Fund, L.P. (together with Fund III, the "Funds"). Deerfield Management Company, L.P. is the investment manager of the Funds. James E. Flynn is the sole member of the general partner of each of Deerfield Mgmt III, L.P., Deerfield Mgmt HIF, L.P. and Deerfield Management Company, L.P.

F3: In accordance with Instruction 4 (b)(iv) to Form 4, the entire amount of the Issuer's securities held by the Funds is reported herein. For purposes of Section 16 of the Securities Exchange Act of 1934, as amended, each Reporting Person disclaims beneficial ownership of any such securities, except to the extent of his/its indirect pecuniary interest therein, if any, and this report shall not be deemed an admission that such Reporting Person is the beneficial owner of such securities for purposes of Section 16 or otherwise.