Transaction Details

Footnotes

Restricted Stock Units ("RSUs") are granted to the reporting person for no additional cash consideration, each of which represents a contingent right to receive one share of common stock upon vesting of these RSUs in one annual installment following the date of grant. | Under the Reporting Person's arrangement with RA Capital Management, L.P. (the "Adviser"), the Reporting Person holds the RSUs and options for the benefit of the RA Capital Healthcare Fund, L.P. (the "Fund") and RA Capital Nexus III Fund, L.P. (the "Nexus Fund III"). The Reporting Person is obligated to turn over to the Adviser any net cash or stock received upon settlement of the RSUs, or exercise of the options, as applicable, which will offset advisory fees owed by the Fund and the Nexus Fund III to the Adviser. The Reporting Person therefore disclaims beneficial ownership of the RSUs or option and underlying common stock, as applicable. | The stock option vests in 12 substantially equal monthly installments following the date of grant.