X0306 4 2020-06-23 0 0001597264 Blueprint Medicines Corp BPMC 0001639935 Lydon Nicholas C/O BLUEPRINT MEDICINES CORPORATION 45 SIDNEY STREET CAMBRIDGE MA 02139 1 0 0 0 Common Stock 2020-06-23 4 S 0 400 80 D 75622 D Effected pursuant to a trading plan adopted on February 27, 2020 pursuant to Rule 10b5-1 under the Securities Exchange Act of 1934, as amended. /s/ Christopher Frankenfield, Attorney-in-Fact 2020-06-25