X0306 4 2021-11-01 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 2021-11-01 4 M 0 1925 18.00 A 32799 D Common Stock 2021-11-01 4 M 0 3252 36.05 A 36051 D Common Stock 2021-11-01 4 S 0 1925 115.03 D 34126 D Common Stock 2021-11-01 4 S 0 1652 112.22 D 32474 D Common Stock 2021-11-01 4 S 0 1600 111.47 D 30874 D Stock Option (Right to Buy) 36.05 2021-11-01 4 M 0 3252 0 D 2027-02-16 Common Stock 3252 24200 D Stock Option (Right to Buy) 18.00 2021-11-01 4 M 0 1925 0 D 2025-04-27 Common Stock 1925 7041 D Effected pursuant to a trading plan adopted on February 19, 2021 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 $115.00 to $115.12 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. The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $111.94 to $112.93 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. The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $111.11 to $111.88 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 was granted on February 16, 2017 and fully vested as of the date hereof. This option was granted on April 27, 2015 and fully vested as of the date hereof. /s/ Ariel Hurley, Attorney-in-Fact 2021-11-03