13D Filing: Polaris Venture Partners VI, L.P. and Editas Medicine Inc (EDIT)

Names of
Reporting Persons.

Polaris Venture Partners VI, L.P. (PVP
VI)

Check the Appropriate Box if a Member
of a Group (See Instructions)

(a)  ☐        (b)  ☒

SEC Use Only

Source of Funds (See Instructions)

WC

Check if Disclosure of Legal
Proceedings Is Required Pursuant to Items 2(d) or 2(e)

☐

Citizenship or Place of
Organization

Delaware

Number of

Shares

Beneficially

Owned by

Each

Reporting

Person

With

Sole Voting Power

1,697,924 shares, except that (i) Polaris Venture Management Co. VI, L.L.C. (PVM
VI), the general partner of PVP VI, may be deemed to have sole power to vote these shares; and (ii) Jonathan A. Flint (Flint), Terrance G. McGuire (McGuire), Brian Chee (Chee), David Barrett
(Barrett), Amir Nashat (Nashat) and Bryce Youngren (Youngren and collectively with Flint, McGuire, Chee, Barrett and Nashat, the Managing Members) are the managing members of PVM VI, and may be deemed
to have shared power to vote these shares.

Shared Voting Power

See response to row 7.

Sole Dispositive Power

1,697,924 shares, except that (i) PVM VI, the general partner of PVP VI, may be deemed to
have sole power to dispose of these shares; and (ii) the Managing Members may be deemed to have shared power to dispose of these shares.

Shared Dispositive Power

See response to row 9.

Aggregate Amount Beneficially Owned by Each Reporting Person

1,697,924

Check if the Aggregate Amount in Row
(11) Excludes Certain Shares (See Instructions)

☐

Percent of Class Represented by Amount
in Row (11)

4.1%

Type of Reporting Person (See
Instructions)

PN