X0306 4 2019-03-01 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 Stock option (right to buy) 14.75 2019-03-01 4 A 0 360000 0.00 A 2029-02-28 Common Stock 360000 360000 D With respect to 290,000 of the shares subject to the option, 25% of such shares shall vest on the one year anniversary of January 1, 2019 (the "Vesting Commencement Date") and thereafter 1/48th of such shares shall vest each month following the one year anniversary of the Vesting Commencement Date, so that all such shares shall be vested four years after the Vesting Commencement Date. With respect to 70,000 of the shares subject to the option, if the Company's 2019 revenues from ZILRETTA product sales are at least a specified amount, then 17,500 of such shares shall vest on January 1, 2020 and thereafter 1/48th of such shares shall vest each month following January 1, 2020, so that all of such shares shall be vested four years after January 1, 2019. /s/ Mark S. Levine, Attorney-in-Fact 2019-03-05