X0306 4 2017-02-01 0 0001640455 Jounce Therapeutics, Inc. JNCE 0001661486 Celgene Switzerland LLC AON HOUSE 30 WOODBOURNE AVENUE PEMBROKE D0 HM 08 BERMUDA 0 0 1 0 0000816284 CELGENE CORP /DE/ 86 MORRIS AVENUE SUMMIT NJ 07901 0 0 1 0 Common Stock 2017-02-01 4 C 0 2831463 A 2831463 D Common Stock 2017-02-01 4 P 0 625000 16.00 A 3456463 D Series B-1 Preferred Stock 2017-02-01 4 C 0 10448100 0.00 D Common Stock 2831463 0 D Upon closing of the Issuer's initial public offering, each share of Series B-1 Preferred Stock automatically converted into 0.271 share of Common Stock without payment of further consideration. The shares had no expiration date. These shares are owned directly by Celgene Switzerland LLC, a wholly-owned subsidiary of Celgene Corporation ("Celgene"), and Celgene has the power to vote, acquire, hold and dispose of all shares. Celgene disclaims beneficial ownership of the securities except to the extent of its pecuniary interest therein. /s/Kevin Mello, Manager, Celgene Switzerland, LLC 2017-02-01 /s/ Peter N. Kellogg, Executive Vice President and Chief Financial Officer, Celgene Corporation 2017-02-01