X0206 3 2019-01-04 0 0001681087 AVROBIO, Inc. AVRO 0001484870 Blackstone Holdings II L.P. C/O THE BLACKSTONE GROUP L.P. 345 PARK AVENUE NEW YORK NY 10154 0 0 1 0 0001762202 Blackstone Clarus III L.L.C. C/O THE BLACKSTONE GROUP L.P. 345 PARK AVENUE NEW YORK NY 10154 0 0 1 0 0001464695 Blackstone Holdings I/II GP Inc C/O THE BLACKSTONE GROUP L.P. 345 PARK AVENUE NEW YORK NY 10154 0 0 1 0 0001393818 Blackstone Group L.P. 345 PARK AVENUE NEW YORK NY 10154 0 0 1 0 0001404071 Blackstone Group Management L.L.C. C/O THE BLACKSTONE GROUP L.P. 345 PARK AVENUE NEW YORK NY 10154 0 0 1 0 0001070844 SCHWARZMAN STEPHEN A C/O THE BLACKSTONE GROUP L.P. 345 PARK AVENUE NEW YORK NY 10154 0 0 1 0 Common Stock 2962325 I See Footnotes These securities are held directly by Clarus Lifesciences III, L.P. ("Clarus III"). Clarus Ventures III GP, L.P. ("Clarus III GP") is the sole general partner of Clarus III. Blackstone Clarus III L.L.C. is the sole general partner of Clarus GP. The sole member of Blackstone Clarus III L.L.C. is Blackstone Holdings II L.P. The sole general partner of Blackstone Holdings II L.P. is Blackstone Holdings I/II GP Inc. The controlling shareholder of Blackstone Holdings I/II GP Inc. is The Blackstone Group L.P. The sole general partner of The Blackstone Group L.P. is Blackstone Group Management L.L.C. Blackstone Group Management L.L.C. is wholly-owned by Blackstone's senior managing directors and controlled by its founder, Stephen A. Schwarzman. Information with respect to each of the Reporting Persons is given solely by such Reporting Person, and no Reporting Person has responsibility for the accuracy or completeness of information supplied by another Reporting Person. Each of such Reporting Persons may be deemed to beneficially own the shares beneficially owned by Clarus III, but each disclaims beneficial ownership of such shares, except to the extent of such Reporting Person's pecuniary interest therein. The filing of this statement shall not be deemed to be an admission that, for purposes of Section 16 of the Securities Exchange Act of 1934 or otherwise, the Reporting Persons are the beneficial owners of any securities reported herein. This Form 3 is being filed in connection with the acquisition by The Blackstone Group L.P. and certain of its affiliates ("Blackstone") of Clarus Ventures, LLC and certain of its affiliates (collectively, "Clarus"). On January 4, 2019, Blackstone integrated the Clarus business into Blackstone (the "Clarus Integration"). As a result of such integration, Blackstone may be deemed to have become the beneficial owner of the securities beneficially owned by Clarus, including the securities of the Issuer. BLACKSTONE CLARUS III L.L.C., By: Blackstone Holdings II L.P., its managing member, By: Blackstone Holdings I/II GP Inc., its general partner, By: /s/ John G. Finley, Name: John G. Finley, Title: Chief Legal Officer 2019-01-10 BLACKSTONE HOLDINGS II L.P., By: Blackstone Holdings I/II GP Inc., its general partner, By: /s/ John G. Finley, Name: John G. Finley, Title: Chief Legal Officer 2019-01-10 BLACKSTONE HOLDINGS I/II GP INC., By: /s/ John G. Finley, Name: John G. Finley, Title: Chief Legal Officer 2019-01-10 THE BLACKSTONE GROUP L.P., By: Blackstone Group Management L.L.C., its general partner, By: /s/ John G. Finley, Name: John G. Finley, Title: Chief Legal Officer 2019-01-10 BLACKSTONE GROUP MANAGEMENT L.L.C., By: /s/ John G. Finley, Name: John G. Finley, Title: Chief Legal Officer 2019-01-10 /s/ Stephen A. Schwarzman 2019-01-10