Security	Date	Code	Shares	Price	A/D	Owned after	D/I	Nature of ownership
Common Stock^F1,F2	Nov 21, 2017	C	1,483,107	—	A	1,483,107	I	by 5AM Ventures IV, L.P.
Common Stock^F3,F2	Nov 21, 2017	C	1,011,623	—	A	2,494,730	I	by 5AM Ventures IV, L.P.
Common Stock^F2	Nov 21, 2017	P	628,572	$14.00	A	3,123,302	I	by 5AM Ventures IV, L.P.
Common Stock^F4,F2	Nov 21, 2017	C	61,795	—	A	61,795	I	by 5AM Co-Investors IV, L.P.
Common Stock^F5,F2	Nov 21, 2017	C	42,150	—	A	103,945	I	by 5AM Co-Investors IV, L.P.
Common Stock^F2	Nov 21, 2017	P	26,190	$14.00	A	130,135	I	by 5AM Co-Investors IV, L.P.

Table II — derivative securities

Security	Conv. / exercise price	Date	Code	Shares	A/D	Exercisable	Expires	Underlying	Underlying shares	D/I
Series A Preferred Stock^F2,F6	—	Nov 21, 2017	C	10,649,003	D	—	—	Common Stock	1,483,107	I
Series B Preferred Stock^F2,F6	—	Nov 21, 2017	C	7,263,649	D	—	—	Common Stock	1,011,623	I
Series A Preferred Stock^F2,F6	—	Nov 21, 2017	C	443,708	D	—	—	Common Stock	61,795	I
Series B Preferred Stock^F2,F6	—	Nov 21, 2017	C	302,652	D	—	—	Common Stock	42,150	I

Explanation of responses

F1Represents the total number of shares of Common Stock received by 5AM Ventures IV, L.P., upon conversion of the Issuer's Series A Preferred Stock in connection with the closing of the Issuer's initial public offering.
F25AM Partners IV, LLC is the general partner of 5AM Ventures IV, L.P. and 5AM Co-Investors IV, L.P. (the "5AM Funds"). Dr. John D. Diekman, Andrew J. Schwab, and Dr. Scott M. Rocklage are managing members of 5AM Partners IV, LLC. 5AM Partners IV, LLC may be deemed to have sole voting and investment power over the shares beneficially owned by the 5AM Funds. Dr. Diekman, Mr. Schwab, and Dr. Rocklage may be deemed to have shared voting and investment power over the shares beneficially by the 5AM Funds. Each of 5AM Partners IV, LLC, Dr. Diekman, Mr. Schwab, and Dr. Rocklage disclaim beneficial ownership of such shares except to the extent of its or their pecuniary interest therein.
F3Represents the total number of shares of Common Stock received by 5AM Ventures IV, L.P., upon conversion of the Issuer's Series B Preferred Stock in connection with the closing of the Issuer's initial public offering.
F4Represents the total number of shares of Common Stock received by 5AM Co-Investors IV, L.P., upon conversion of the Issuer's Series A Preferred Stock in connection with the closing of the Issuer's initial public offering.
F5Represents the total number of shares of Common Stock received by 5AM Co-Investors IV, L.P., upon conversion of the Issuer's Series B Preferred Stock in connection with the closing of the Issuer's initial public offering.
F6All series of Convertible Preferred Stock automatically converted into the Issuer's Common Stock on a 7.180193-for-1 basis on November 21, 2017 and had no expiration date.