X0206 3 2018-07-18 0 0001434418 CONSTELLATION PHARMACEUTICALS INC CNST 0001616230 Senderowicz Adrian C/O CONSTELLATION PHARMACEUTICALS, INC. 215 FIRST STREET, SUITE 200 CAMBRIDGE MA 02142 0 1 0 0 Chief Medical Officer Stock Option (right to buy) 5.51 2027-07-10 Common Stock 145335 D Stock Option (right to buy) 5.51 2027-07-10 Common Stock 72667 D Stock Option (right to buy) 7.60 2028-03-05 Common Stock 37696 D Stock Option (right to buy) 8.04 2028-04-08 Common Stock 37696 D This option was granted on July 11, 2017, and has vested as to 25% of the shares underlying the option as of July 10, 2018 with the remainder vesting quarterly through July 10, 2021. This option was granted on July 11, 2017 and is scheduled to vest as to 100% of the shares underlying the option on July 10, 2023, subject to accelerated vesting as to: 4,542 shares upon the satisfaction of an objective clinical milestone, which milestone has been achieved, 4,542 shares upon the satisfaction of an objective clinical milestone, which milestone has been achieved, 9,083 shares upon the satisfaction of an objective clinical milestone, 27,250 shares upon the satisfaction of an objective clinical or regulatory milestone and 27,250 shares upon the satisfaction of an objective clinical or regulatory milestone. (Continued from footnote 2) If and when one or more of these performance milestones are achieved, the number of shares associated with such milestone will convert to time-based vesting from July 10, 2017, with shares underlying the option vesting in equal quarterly installments until July 10, 2021. Upon the commencement of trading of the Issuer's Common Stock on the Nasdaq Stock Market, 63,584 shares of Common Stock will begin vesting in equal quarterly installments until the four-year anniversary of the commencement of trading of the Issuer's Common Stock on the Nasdaq Stock Market. The remaining 9,083 shares will continue to vest as described above. This option was granted on March 6, 2018. The shares underlying the option are scheduled to vest in equal quarterly installments through March 6, 2022. This option was granted on April 9, 2018. The shares underlying the option are scheduled to vest in equal quarterly installments through April 9, 2022. Exhibit Index: 24.1 Power of Attorney /s/ Emma Reeve, as attorney-in-fact for Adrian Senderowicz 2018-07-18