X0306 4 2018-11-01 0 0001597264 Blueprint Medicines Corp BPMC 0001756941 Rossi Christina C/O BLUEPRINT MEDICINES CORPORATION 45 SIDNEY STREET CAMBRIDGE MA 02139 0 1 0 0 Chief Commercial Officer Stock Option (Right to Buy) 65.75 2018-11-01 4 A 0 80000 0 A 2028-11-01 Common Stock 80000 80000 D Restricted Stock Units 2018-11-01 4 A 0 4500 0 A Common Stock 4500 4500 D In accordance with the Issuer's equity award grant policy, this option was granted effective as of the first day of the month following the commencement of the Reporting Person's employment with the Issuer on October 29, 2018. This option vests with respect to 25% of the shares underlying the option on November 1, 2019 and as to an additional 1/48th of the shares underlying the option each month thereafter. Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock. The restricted stock units vest in four equal annual installments on November 1, 2019, 2020, 2021 and 2022. /s/ Christopher Frankenfield, Attorney-in-Fact 2018-11-05