X0206 3 2021-01-01 0 0001419600 Flexion Therapeutics Inc FLXN 0001837852 Muzikant Adam C/O FLEXION THERAPEUTICS, INC. 10 MALL ROAD, SUITE 301 BURLINGTON MA 01803 0 1 0 0 Chief Business Officer Common Stock 77460 D Stock option (right to buy) 16.35 2026-09-11 Common Stock 40000 D Stock option (right to buy) 18.56 2026-12-19 Common Stock 25000 D Stock option (right to buy) 22.31 2028-01-31 Common Stock 16667 D Stock option (right to buy) 14.75 2029-02-28 Common Stock 11000 D Amount includes 4,167 shares subject to a restricted stock unit award granted on February 1, 2018; 22,000 shares subject to a restricted stock unit award granted on March 1, 2019; 18,000 shares subject to a restricted stock unit award granted on March 2, 2020 and 18,000 shares subject to a restricted stock unit award granted on July 16, 2020. The stock option is fully vested. 1/4th of the shares subject to the option vest one year after December 20, 2016, with 1/48th of the shares vesting monthly thereafter over the next 3 years. 1/4th of the shares subject to the option vest one year after January 1, 2018, with 1/48th of the shares vesting monthly thereafter over the next 3 years. 1/4th of the shares subject to the option vest one year after January 1, 2019, with 1/48th of the shares vesting monthly thereafter over the next 3 years. /s/ Christopher Martin, Attorney-in-Fact 2021-01-06