X0306 4 2019-07-08 0 0001597264 Blueprint Medicines Corp BPMC 0001638468 Boral Anthony L. C/O BLUEPRINT MEDICINES CORPORATION 45 SIDNEY STREET CAMBRIDGE MA 02139 0 1 0 0 Chief Medical Officer Common Stock 2019-07-08 4 M 0 10000 8.80 A 10000 D Common Stock 2019-07-08 4 S 0 5215 94.18 D 4785 D Common Stock 2019-07-08 4 S 0 4685 93.56 D 100 D Common Stock 2019-07-08 4 S 0 100 92.79 D 0 D Stock Option (Right to Buy) 8.80 2019-07-08 4 M 0 10000 0 D 2025-02-10 Common Stock 10000 23030 D Effected pursuant to a trading plan adopted on April 3, 2019 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 $93.86 to $94.85 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 ranges set forth in footnotes (2) through (4) of this Form 4. The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $92.87 to $93.85 per share. The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $92.75 to $92.83 per share. This option was granted on February 10, 2015. This option vested with respect to 25% of the shares underlying the option on February 9, 2016 and as to an additional 1/48th of the shares underlying the option each month thereafter. /s/ Christopher Frankenfield, Attorney-in-Fact 2019-07-10