X0306 4 2018-02-01 0 0001419600 Flexion Therapeutics Inc FLXN 0001597407 Clayman Michael D. C/O FLEXION THERAPEUTICS, INC. 10 MALL ROAD, SUITE 301 BURLINGTON MA 01803 1 1 0 0 President and CEO Common Stock 2018-02-01 4 A 0 29167 0.00 A 64728 D Common Stock 294383 I By the Michael D. Clayman 2006 Revocable Trust Common Stock 24600 I By the Michael D. Clayman Irrevocable Trust Common Stock 388683 I By Versant Development Fund III, LLC Stock option (right to buy) 22.31 2018-02-01 4 A 0 116667 0.00 A 2028-01-31 Common Stock 116667 116667 D The shares are held by Versant Development Fund III, LLC. The Reporting Person is a manager and minority member of Versant Development Fund III, LLC. The Reporting Person disclaims any beneficial ownership of the shares held by Versant Development Fund III, LLC except to the extent of his pecuniary interest in these shares. Twenty-five percent (25%) of the shares subject to the option shall vest one year after January 1, 2018; thereafter one-forty-eighth (1/48th) of the shares subject to the option shall vest each month following the one year anniversary of January 1, 2018, so that all of the shares subject to the option shall be vested four (4) years after January 1, 2018. /s/ Mark S. Levine, Attorney-in-Fact 2018-02-02