X0306 4 2020-05-26 0 0001383701 Histogen Inc. HSTO 0001810100 Crean David Hugh C/O HISTOGEN INC. 10655 SORRENTO VALLEY RD., STE 200 SAN DIEGO CA 92121 1 0 0 0 Stock Option (right to buy) 3.70 2017-05-22 4 J 0 17210 0.00 A 2027-05-22 Common Stock 17210 17210 D Stock Option (right to buy) 3.84 2017-10-25 4 J 0 4302 0.00 A 2027-10-25 Common Stock 4302 4302 D Stock Option (right to buy) 3.84 2018-05-02 4 J 0 35855 0.00 A 2028-05-02 Common Stock 35855 35855 D Shares of common stock of the corporation formerly known as Histogen Inc. ("Histogen") were converted into shares of common stock of the Issuer pursuant to that certain Agreement and Plan of Merger and Reorganization, dated as of January 28, 2020, by and among the Issuer, Chinook Merger Sub, Inc. and Histogen (the "Merger Agreement"). Pursuant to the terms of the Merger Agreement, each share of Histogen common stock was exchanged for 1.4342 shares of the Issuer's common stock (the "Conversion"). Immediately following the merger, the Issuer changed its name to Histogen Inc. All share numbers reflect the one-for-ten reverse stock split (the "Reverse Split") effected by the Issuer immediately prior to the completion of the merger. Fully vested. Shares subject to the option and the exercise price have been adjusted based upon the Conversion and Reverse Split. 25% of the shares subject to the option vested on 03/12/2018 and 1/48 of the shares subject to the option shall vest monthly thereafter. Shares subject to the option and the exercise price have been adjusted based upon the Conversion and Reverse Split. /s/ Richard W. Pascoe as attorney-in-fact for David Hugh Crean 2020-05-28