X0306 4 2018-06-25 0 0001681087 AVROBIO, Inc. AVRO 0001597143 Clarus Lifesciences III, L.P. 101 MAIN STREET, SUITE 1210 CAMBRIDGE MA 02142 0 0 1 0 0001620148 Clarus Ventures III GP, L.P. 101 MAIN STREET, SUITE 1210 CAMBRIDGE MA 02142 0 0 1 0 0001664942 Clarus Ventures III, LLC 101 MAIN STREET, SUITE 1210 CAMBRIDGE MA 02142 0 0 1 0 Common Stock 2018-06-25 4 C 0 2283434 A 2283434 I See Footnote Common Stock 2018-06-25 4 C 0 678891 A 2962325 I See Footnote Series A Preferred Stock 2018-06-25 4 C 0 9435150 0.00 D Common Stock 2283434 0 I See footnote Series B Preferred Stock 2018-06-25 4 C 0 2805179 0.00 D Common Stock 678891 0 I See footnote Represents the total number of shares of Common Stock received by Clarus Lifesciences III, L.P. ("Clarus") upon the conversion of the Issuer's Series A Preferred Stock in connection with the closing of the Issuer's initial public offering. The shares are held directly by Clarus. The general partner of Clarus is Clarus Ventures III GP, L.P. ("GPLP"). Clarus Ventures III, LLC, ("LLC") is the general partner of GPLP. Each of Nicholas Galakatos, Dennis Henner, Robert Liptak, Scott Requadt, Nicholas Simon, and Kurt Wheeler, as individual managing directors of the LLC, may be deemed to beneficially own certain of the shares held of record by Clarus. Each of Messrs. Galakatos, Henner, Liptak, Requadt, Simon and Wheeler disclaims beneficial ownership of all shares held of record by Clarus in which he does not have an actual pecuniary interest. Scott G. Requadt is a member of LLC and a member of the Issuer's board of directors. Mr. Requadt disclaims beneficial ownership of such shares, except to the extent of his proportionate pecuniary interest therein, if any. Represents the total number of shares of Common Stock received by Clarus upon the conversion of the Issuer's Series B Preferred Stock in connection with the closing of the Issuer's initial public offering. All series of Convertible Preferred Stock automatically converted into the Issuer's Common Stock on a 4.132-for-1 basis on June 25, 2018 and had no expiration date. Clarus Lifesciences III, L.P., By: its General Partner, Clarus Ventures III GP, L.P., By: its General Partner, Clarus Ventures III, LLC, By: Robert Liptak, Managing Director, /s/ Robert Liptak 2018-06-25 Clarus Ventures III GP, L.P., By: its General Partner, Clarus Ventures III, LLC, By: Robert Liptak, Managing Director, /s/ Robert Liptak 2018-06-25 Clarus Ventures III, LLC, By: Robert Liptak, Managing Director, /s/ Robert Liptak 2018-06-25