Security	Conv. / exercise price	Date	Code	Shares	A/D	Exercisable	Expires	Underlying	Underlying shares	Owned after	D/I
Series A Preferred Stock^F2,F3	—	Apr 2, 2018	C	4,204,502	D	—	—	Common Stock	4,204,502	0	I
Series B Preferred Stock^F2,F3	—	Apr 2, 2018	C	1,187,535	D	—	—	Common Stock	1,187,535	0	I

Explanation of responses

F1Following the transactions reported herein, includes 6,453,195 shares of Common Stock held of record by 5AM Ventures IV, L.P. ("Ventures IV") and 268,881 shares of Common Stock held of record by 5AM Co-Investors IV, L.P. ("Co-Investors IV").
F25AM Partners IV, LLC ("Partners IV") is the sole general partner of Ventures IV and Co-Investors IV. Dr. John Diekman, Andrew J. Schwab and Dr. Scott M. Rocklage, are the managing members of Partners IV, and have shared voting and investment power over the shares beneficially owned by Ventures IV and Co-Investors IV. Each of Partners IV, Dr. Diekman, Mr. Schwab, and Dr. Rocklage disclaims beneficial ownership of such shares except to the extent of its or their pecuniary interest therein.
F3Upon closing of the Issuer's initial public offering, each share of Series A Preferred Stock and Series B Preferred Stock was automatically converted into one share of the Issuer's common stock.