Board of Directors of Generation Bio Co. appointed Dannielle Appelhans to fill the newly created vacancy as a Class III director and as a member of the Company's N&G Committee, with a term of office to continue until the Company's 2023 annual meeting of stockholders and until her successor has been duly elected and qualified, or until her earlier death, resignation or removal. Ms. Appelhans will receive compensation as a non-employee director in accordance with the Company's non-employee director compensation program that the Board approved in April 2022 Pursuant to the Program, Ms. Appelhans will be entitled to receive a cash retainer of $40,000 per year for her service on the Board and $4,000 per year for her service as a member of the N&G Committee.

This retainer is payable in arrears in four equal quarterly installments on the last day of each quarter, provided that the amount of such payment will be prorated for the third quarter of 2022. In addition, under the Program, Ms. Appelhans has received an initial grant of an option to purchase 38,400 shares of the Company's common stock under the Company's 2020 Stock Incentive Plan that will vest monthly over a three-year period, subject to Ms. Appelhans' continued service as a director through each applicable vesting date. The option grant has an exercise price of $7.18, equal to the closing sales price of the Company's common stock on July 15, 2022 as reported on The Nasdaq Global Select Market, and a term of 10 years, subject to earlier termination for cessation of continuous service.

Further, under the Program, on the date of each annual meeting of stockholders commencing in 2023, Ms. Appelhans will be entitled to receive an option to purchase 19,200 shares of the Company's common stock under the 2020 Plan that will vest in full on the earlier of the first anniversary of the grant date and the date of the annual meeting of stockholders in the year immediately following the year in which the option was granted, will be issued at an exercise price equal to the closing sales price of the Company's common stock as reported on The Nasdaq Global Select Market on the date of grant and will have a term of ten years. In conjunction with Ms. Appelhans' appointment, the Company and Ms. Appelhans entered into the Company's standard indemnification agreement, a copy of which was filed as Exhibit 10.10 to the Company's Registration Statement on Form S-1 filed with the Securities and Exchange Commission on May 22, 2020.