X0206 3 2021-10-22 0 0001395937 Syndax Pharmaceuticals Inc SNDX 0001891979 Nolte Alexander C/O SYNDAX PHARMACEUTICALS, INC. 35 GATEHOUSE DRIVE, BUILDING D, FLOOR 3 WALTHAM MA 02451 false true false false Chief Accounting Officer Stock Options (Right to buy) 21.36 2031-02-03 Common Stock 62000.00 D Stock Options (Right to buy) 19.36 2031-09-15 Common Stock 35000.00 D Stock Options (Right to buy) 18.03 2030-05-08 Common Stock 5000.00 D Stock Options (Right to buy) 9.63 2028-02-08 Common Stock 2000.00 D Stock Options (Right to buy) 9.47 2030-02-12 Common Stock 16000.00 D Stock Options (Right to buy) 9.24 2027-05-01 Common Stock 11667.00 D Stock Options (Right to buy) 9.00 2029-07-26 Common Stock 7000.00 D Stock Options (Right to buy) 6.38 2029-02-06 Common Stock 18000.00 D One forty-eighth (1/48th) of the total number of shares underlying the option vest monthly thereafter on the last day of each month, beginning February 28, 2021, subject to the reporting person's continuous service on the relevant vesting dates. One forty-eighth (1/48th) of the total number of shares underlying the option vest monthly thereafter on the last day of each month, beginning September 30, 2021, subject to the reporting person's continuous service on the relevant vesting dates. One forty-eighth (1/48th) of the total number of shares underlying the option vest monthly thereafter on the last day of each month, beginning May 31, 2020, subject to the reporting person's continuous service on the relevant vesting dates. One forty-eighth (1/48th) of the total number of shares underlying the option vest monthly thereafter on the last day of each month, beginning February 28, 2018, subject to the reporting person's continuous service on the relevant vesting dates. One forty-eighth (1/48th) of the total number of shares underlying the option vest monthly thereafter on the last day of each month, beginning February 29, 2020, subject to the reporting person's continuous service on the relevant vesting dates. Twenty-five percent (25%) of the total number of shares underlying the option vested on May 1, 2018, and one forty-eighth (1/48th) of the total number of shares underlying the option vest monthly thereafter on the last day of each month, subject to the reporting person's continuous service on the relevant vesting dates. One forty-eighth (1/48th) of the total number of shares underlying the option vest monthly thereafter on the last day of each month, beginning July 31, 2019, subject to the reporting person's continuous service on the relevant vesting dates. One forty-eighth (1/48th) of the total number of shares underlying the option vest monthly thereafter on the last day of each month, beginning February 28, 2019, subject to the reporting person's continuous service on the relevant vesting dates. /s/ Michael A. Metzger, as Attorney-in-Fact 2021-11-04