X0306 4 2018-07-23 1 0001434418 CONSTELLATION PHARMACEUTICALS INC CNST 0001055951 ORBIMED ADVISORS LLC 601 LEXINGTON AVENUE, 54TH FLOOR NEW YORK NY 10022 0 0 1 0 0001673892 OrbiMed Global Healthcare GP LLC 601 LEXINGTON AVENUE, 54TH FLOOR NEW YORK NY 10022 0 0 1 0 0001682115 OrbiMed Capital GP VI LLC 601 LEXINGTON AVENUE, 54TH FLOOR NEW YORK NY 10022 0 0 1 0 Common Stock 2018-07-23 4 C 0 317921 A 317921 I See footnote Common Stock 2018-07-23 4 P 0 100000 15.00 A 417921 I See footnote Common Stock 2018-07-23 4 C 0 317921 A 317921 I See footnote Common Stock 2018-07-23 4 P 0 100000 15.00 A 417921 I See footnote Series F Preferred Stock 2018-07-23 4 C 0 3500000 0.00 D Common Stock 317921 0 I See footnote Series F Preferred Stock 2018-07-23 4 C 0 3500000 0.00 D Common Stock 317921 0 I See footnote On July 23, 2018, the Series F Preferred Stock converted into Common Stock on a 11.009-for-one basis upon the closing of the Issuer's initial public offering without payment of consideration. The Series F Preferred Stock was convertible at any time at the holder's election and automatically upon the closing of the Issuer's initial pubic offering. The shares had no expiration date. These securities are held of record by OrbiMed Global Healthcare Master Fund, L.P. OrbiMed Global Healthcare GP LLC is the sole general partner of OrbiMed Global Healthcare Master Fund, L.P., and OrbiMed Advisors LLC is the managing member of OrbiMed Global Healthcare GP LLC. By virtue of such relationships, OrbiMed Global Healthcare GP LLC and OrbiMed Advisors LLC may be deemed to have voting and investment power over the securities held by OrbiMed Global Healthcare Master Fund, L.P. and as a result may be deemed to have beneficial ownership over such securities. These securities are held of record by OrbiMed Private Investments VI, LP. OrbiMed Capital GP VI LLC is the sole general partner of OrbiMed Private Investments VI, LP, and OrbiMed Advisors LLC is the managing member of OrbiMed Capital GP VI LLC. By virtue of such relationships, OrbiMed Capital GP VI LLC and OrbiMed Advisors LLC may be deemed to have voting and investment power over the securities held by OrbiMed Private Investments VI, LP and as a result may be deemed to have beneficial ownership over such securities. This report on Form 4 is jointly filed by OrbiMed Capital GP VI LLC, OrbiMed Global Healthcare GP LLC and OrbiMed Advisors LLC. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. This report shall not be deemed an admission that any of the Reporting Persons is a beneficial owner of such securities for the purpose of Section 16 of the Exchange Act, or for any other purpose. /s/ Douglas Coon, as Attorney-in-Fact for Jonathan T. Silverstein 2018-07-24 /s/ Douglas Coon, as Attorney-in-Fact for Sven H. Borho 2018-07-24 /s/ Douglas Coon, as Attorney-in-Fact for Carl L. Gordon 2018-07-24