Security	Date	Code	Shares	Price	A/D	Owned after	D/I	Nature of ownership
Common Stock^F3,F1,F4	Oct 1, 2018	C	2,862,649	—	A	2,862,649	I	See footnotes
Common Stock^F3,F1,F4	Oct 1, 2018	C	1,338,679	—	A	4,201,328	I	See footnotes
Common Stock^F3,F1,F4	Oct 1, 2018	C	662,864	—	A	4,864,192	I	See footnotes
Common Stock^F3,F2,F4	Oct 1, 2018	C	73,777	—	A	73,777	I	See footnotes
Common Stock^F3,F2,F4	Oct 1, 2018	C	34,500	—	A	108,277	I	See footnotes
Common Stock^F3,F2,F4	Oct 1, 2018	C	17,083	—	A	125,360	I	See footnotes

Table II — derivative securities

Security	Conv. / exercise price	Date	Code	Shares	A/D	Exercisable	Expires	Underlying	Underlying shares	D/I
Series A Preferred Stock^F1,F4,F3	—	Oct 1, 2018	C	9,303,611	D	—	—	Common Stock	2,862,649	I
Series A Preferred Stock^F2,F4,F3	—	Oct 1, 2018	C	239,776	D	—	—	Common Stock	73,777	I
Series B Preferred Stock^F1,F4,F3	—	Oct 1, 2018	C	4,350,709	D	—	—	Common Stock	1,338,679	I
Series B Preferred Stock^F2,F4,F3	—	Oct 1, 2018	C	112,128	D	—	—	Common Stock	34,500	I
Series C Preferred Stock^F1,F4,F3	—	Oct 1, 2018	C	2,154,311	D	—	—	Common Stock	662,864	I
Series C Preferred Stock^F2,F4,F3	—	Oct 1, 2018	C	55,522	D	—	—	Common Stock	17,083	I

Explanation of responses

F1These Secruties are held of record by 5AM Ventures III, L.P. ("Ventures III").
F2These Securities are held of record by 5AM Co-Investors III, L.P. ("Co-Investors III").
F3On October 1, 2018, the Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock converted into Common Stock on a 3.25-for-one basis, upon the closing of the Issuer's initial public offering without payment of consideration. The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock were convertible at any time at the holder's election and automatically upon the closing of the Issuer's initial public offering. The shares had no expiration date.
F45AM Partners III, LLC ("Partners III") is the sole general partner of Ventures III and Co-Investors III. Dr. John D. Diekman, Andrew J. Schwab and Dr. Scott M. Rocklage, are the managing members of Partners III, and may be deemed to have shared voting and investment power over the shares beneficially owned by Ventures III and Co-Investors III. Each of Partners III, Dr. Diekman, Mr. Schwab and Dr. Rocklage disclaim beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.