Partner Fund Management Has Confidence In Blueprint Medicines Corp (BPMC)

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Page 13 of 13 – SEC Filing
CUSIP No. 09627Y109 13G Page 13 of 13 Pages

After reasonable inquiry
and to the best of its knowledge and belief, the undersigned certify that the information set forth in this statement is true,
complete and correct.

Dated this 28th day of March, 2016.

PARTNER FUND MANAGEMENT, L.P. PARTNER FUND MANAGEMENT GP, LLC
By: Partner Fund Management GP, LLC By: /s/ Darin Sadow
its general partner Darin Sadow, Authorized Signatory
By: /s/ Darin Sadow
Darin Sadow, Authorized Signatory
PARTNER INVESTMENT MANAGEMENT, L.P. PARTNER INVESTMENT MANAGEMENT GP, LLC
By: Partner Investment Management GP, LLC, By: /s/ Darin Sadow
its general partner Darin Sadow, Authorized Signatory
By: /s/ Darin Sadow
Darin Sadow, Authorized Signatory
BRIAN D. GROSSMAN CHRISTOPHER M. JAMES
By: /s/ Darin Sadow By: /s/ Darin Sadow
Darin Sadow, attorney-in-fact* Darin Sadow, attorney-in-fact**
* Darin Sadow is signing on behalf of Brian Grossman as attorney-in-fact pursuant to a power of attorney
dated August 4, 2011, and incorporated by reference herein. The power of attorney was filed as an attachment to a filing by certain
of the Reporting Persons on Schedule 13G for K-V Pharmaceutical Company on August 5, 2011.
** Darin Sadow is signing on behalf of Christopher M. James as attorney-in-fact pursuant to a power of
attorney dated August 4, 2011, and incorporated by reference herein. The power of attorney was filed as an attachment to a filing
by certain of the Reporting Persons on Schedule 13G for K-V Pharmaceutical Company on August 5, 2011.

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