X0306 4 2019-12-17 1 0001609351 Spark Therapeutics, Inc. ONCE 0001631248 High Katherine A 3737 MARKET STREET SUITE 1300 PHILADELPHIA PA 19104 1 1 0 0 See Remarks Common Stock 2019-12-17 4 U 0 278834 114.50 D 0 D Stock Option (Right to Buy) 42.73 2019-12-17 4 D 0 35000 0.00 D 2029-01-15 Common Stock 35000 0 D Stock Option (Right to Buy) 50.55 2019-12-17 4 D 0 23625 0.00 D 2028-01-17 Common Stock 23625 0 D Stock Option (Right to Buy) 56.17 2019-12-17 4 D 0 15750 0.00 D 2027-01-17 Common Stock 15750 0 D Stock Option (Right to Buy) 40.44 2019-12-17 4 D 0 13750 0.00 D 2026-01-04 Common Stock 13750 0 D Restricted Stock Units 0.00 2019-12-17 4 D 0 21250 0.00 D Common Stock 21250 0 D Disposed of pursuant to the Agreement and Plan of Merger, dated February 22, 2019, by and between Spark Therapeutics, Inc. ("Spark"), Roche Holdings, Inc. ("Roche") and 022019 Merger Subsidiary, Inc. ("Merger Sub") (the "Merger Agreement" and the transactions contemplated thereby, the "Merger"), whereby Roche caused Merger Sub to conduct a tender offer for all of the issued and outstanding shares of common stock, par value $0.001 per share, of Spark, at a price of $114.50 per share. On December 17, 2019, Merger Sub irrevocably accepted for payment all shares that were validly tendered and not withdrawn. Pursuant to the terms of the Merger Agreement, immediately prior to the effective time of the Merger, each outstanding Spark stock option, whether vested or unvested, was converted into the right to an amount in cash (less applicable tax withholdings) equal to the product of (a) the excess of $114.50 over the per share exercise price of such stock option and (b) the total number of shares of common stock subject to such stock option. Pursuant to the terms of the Merger Agreement, immediately prior to the effective time of the Merger, each outstanding Spark restricted stock unit, whether vested or unvested, was canceled and converted into the right to receive $114.50 in cash (less applicable tax withholdings). President and Head of Research and Development /s/ Joseph W. La Barge, Attorney-in-Fact 2019-12-17