X0306 4 2020-07-28 1 0001693011 Inozyme Pharma, Inc. INZY 0001551966 Hopfner Robert Lorne C/O INOZYME PHARMA, INC. 321 SUMMER STREET, SUITE 400 BOSTON MA 02210 1 0 1 0 Common Stock 2020-07-28 4 C 0 1403654 A 1403654 I By Pivotal bioVenture Partners Fund I, L.P. Common Stock 2020-07-28 4 P 0 187500 16.00 A 1591154 I By Pivotal bioVenture Partners Fund I, L.P. Series A-2 Convertible Preferred Stock 2020-07-28 4 C 0 10489510 0.00 D Common Stock 1403654 0 I By Pivotal bioVenture Partners Fund I, L.P. On July 28, 2020, the Series A-2 Convertible Preferred Stock automatically converted into Common Stock on a 7.4730-for-1 basis upon the closing of the Issuer's initial public offering without payment of consideration. The Series A-2 Convertible Preferred Stock was convertible at any time at the holder's election and automatically upon the closing of the Issuer's initial public offering. The shares had no expiration date. The shares are held of record by Pivotal bioVenture Partners Fund I, L.P. ("Pivotal"). The general partner of Pivotal is Pivotal bioVenture Partners Fund I G.P., L.P. ("Pivotal GP"). The general partner of Pivotal GP is Pivotal bioVenture Partners Fund I U.G.P., Ltd. Robert Hopfner, Vincent Cheung, Peter Bisgaard, and Heather Preston are managing partners of Pivotal's investment advisor and may be deemed to have shared voting and dispositive power over the shares owned by Pivotal. Dr. Hopfner disclaims beneficial ownership over such shares except to the extent of any pecuniary interest therein. /s/ Stephen Basso, as attorney-in-fact for Robert Hopfner 2020-07-28