X0306 4 2017-02-13 false 0001395937 Syndax Pharmaceuticals Inc SNDX 0001294354 Shea Richard P C/O SYNDAX PHARMACEUTICALS, INC. 400 TOTTEN POND ROAD, SUITE 110 WALTHAM MA 02451 false true false false Chief Financial Officer Stock Option (Right to Buy) 10.20 2017-02-13 4 A false 125000.00 0.00 A 2027-02-13 Common Stock 125000.00 125000.00 D Twenty-five percent (25%) of the total number of shares underlying the option shall vest on February 13, 2018, and one forty-eighth (1/48th) of the total number of shares underlying the option shall vest monthly thereafter on the last day of each month, subject to the reporting person's continuous service on the relevant vesting dates. /s/ Michael A. Metzger, Attorney-in-Fact 2017-02-15