X0306 4 2020-06-22 0 0001597264 Blueprint Medicines Corp BPMC 0001802970 Durso-Bumpus Debra C/O BLUEPRINT MEDICINES CORPORATION 45 SIDNEY STREET CAMBRIDGE MA 02139 0 1 0 0 Chief People Officer Common Stock 2020-06-22 4 M 0 2300 36.05 A 21805 D Common Stock 2020-06-22 4 S 0 2300 80.07 D 19505 D Stock Option (Right to Buy) 36.05 2020-06-22 4 M 0 2300 0 D 2027-02-16 Common Stock 2300 30200 D Effected pursuant to a trading plan adopted on May 15, 2020 pursuant to Rule 10b5-1 under the Securities Exchange Act of 1934, as amended. The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $80.00 to $80.19 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth herein. This option vested with respect to 1/48th of the shares underlying the option on March 16, 2017 and vests as to an additional 1/48th of the shares underlying the option each month thereafter. /s/ Christopher Frankenfield, Attorney-in-Fact 2020-06-24