Blueprint Medicines Corp (BPMC): Biotechnology Value Fund Reports 10.4% Stake

Page 8 of 11 – SEC Filing

Partners, as the general partner of BVF, BVF2, the investment manager of Trading Fund OS, and the sole member of Partners OS, may be deemed to beneficially own the 2,840,251 shares of Common Stock beneficially owned in the aggregate by BVF, BVF2, Trading Fund OS, and certain Partners management accounts (the “Partners Management Accounts”), including 536,476 shares of Common Stock held in the Partners Management Accounts.

BVF Inc., as the general partner of Partners, may be deemed to beneficially own the 2,840,251 shares of Common Stock beneficially owned by Partners.

Mr. Lampert, as a director and officer of BVF Inc., may be deemed to beneficially own the 2,840,251 shares of Common Stock beneficially owned by BVF Inc.

The foregoing should not be construed in and of itself as an admission by any Reporting Person as to beneficial ownership of any shares of Common Stock owned by another Reporting Person. Partners OS disclaims beneficial ownership of the shares of Common Stock beneficially owned by Trading Fund OS. Each of Partners, BVF Inc. and Mr. Lampert disclaims beneficial ownership of the shares of Common Stock beneficially owned by BVF, BVF2, Trading Fund OS, and the Partners Management Accounts, and the filing of this statement shall not be construed as an admission that any such person or entity is the beneficial owner of any such securities.

(b)

Percent of class:

The following percentages are based on 27,237,950 shares of Common Stock outstanding as of April 25, 2016, as disclosed in the Issuer’s Definitive Proxy Statement filed on Schedule 14A with the Securities and Exchange Commission on April 28, 2016.

As of the close of business on May 3, 2016 (i) BVF beneficially owned approximately 4.9% of the outstanding shares of Common Stock, (ii) BVF2 beneficially owned approximately 2.9% of the outstanding shares of Common Stock, (iii) Trading Fund OS beneficially owned less than 1% of the outstanding shares of Common Stock (iv) Partners OS may be deemed to beneficially own less than 1% of the outstanding shares of Common Stock, and (v) each of Partners, BVF Inc. and Mr. Lampert may be deemed to beneficially own approximately 10.4% of the outstanding shares of Common Stock (approximately 2.0% of which is held in the Partners Management Accounts).

(c)

Number of shares as to which such person has:

(i)

Sole power to vote or to direct the vote

See Cover Pages Items 5-9.

(ii)

Shared power to vote or to direct the vote

See Cover Pages Items 5-9.

(iii)

Sole power to dispose or to direct the disposition of

See Cover Pages Items 5-9.