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

Names of
Reporting Persons.

Terrance G. McGuire (McGuire)

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

(a)  ☐        (b)  ☒

SEC Use Only

Source of Funds (See Instructions)

AF

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

☐

Citizenship or Place of
Organization

USA

Number of

Shares

Beneficially

Owned by

Each

Reporting

Person

With

Sole Voting Power

1,797,144 shares, of which 1,697,924 shares are directly owned by PVP VI and 99,220
shares are directly owned by PVPFF VI, except that (i) PVM VI, as the general partner of PVP VI and PVPFF VI, may be deemed to have sole power to vote the Fund VI Shares; and (ii) Flint, Chee, Barrett, Nashat and Youngren, as managing members of PVM
VI, may be deemed to have shared power to vote the Fund VI Shares.

Shared Voting Power

See response to row 7.

Sole Dispositive Power

1,797,144 shares, of which 1,697,924 shares are directly owned by PVP VI and 99,220
shares are directly owned by PVPFF VI, except that (i) PVM VI, as the general partner of PVP VI and PVPFF VI, may be deemed to have sole power to dispose of the Fund VI Shares; and (ii) Flint, Chee, Barrett, Nashat and Youngren, as managing members
of PVM VI, may be deemed to have shared power to dispose of the Fund VI Shares.

Shared Dispositive Power

See response to row 9.

Aggregate Amount Beneficially Owned by Each Reporting Person

1,797,144 shares

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

☐

Percent of Class Represented by Amount
in Row (11)

4.3%

Type of Reporting Person (See
Instructions)

IN