Security	Date	Code	Shares	Price	A/D	Owned after	D/I
Common Stock^F1	Jul 24, 2018	P	266,667	$15.00	A	266,667	D
Common Stock^F2,F1	Jul 24, 2018	C	994,688	$0.00	A	1,261,355	D
Common Stock^F3,F1	Jul 24, 2018	C	2,579,881	$0.00	A	3,841,236	D
Common Stock^F4,F1	Jul 24, 2018	C	1,013,547	$0.00	A	4,854,783	D

Table II — derivative securities

Security	Conv. / exercise price	Date	Code	Shares	A/D	Exercisable	Expires	Underlying	Underlying shares	Owned after	D/I
Series Seed Warrants (right to buy)^F1,F5	—	Jul 24, 2018	C	25,000	D	—	—	Series Seed Preferred Stock	25,000	0	D
Common Stock Warrants (right to buy)^F1,F5	—	Jul 24, 2018	C	248,672	A	—	—	Common Stock	248,672	248,672	D
Series Seed Preferred Stock^F1,F2	—	Jul 24, 2018	C	100,000	D	—	—	Common Stock	994,688	0	D
Series A Convertible Preferred Stock^F1,F3	—	Jul 24, 2018	C	259,366	D	—	—	Common Stock	2,579,881	0	D
Series B Convertible Preferred Stock^F1,F4	—	Jul 24, 2018	C	101,896	D	—	—	Common Stock	1,013,547	0	D
Common Stock Option^F6	$15.00	Jul 19, 2018	A	13,500	A	—	—	Common Stock	13,500	13,500	D

Explanation of responses

F1The reported securities are beneficially owned by Omega Fund IV, L.P. ("Omega IV"). The reported securities may be deemed to be beneficially owned by each of Omega Fund IV GP, L.P. ("Omega IV GP"), as the general partner of Omega IV, and Omega Fund IV GP Manager, Ltd. ("Omega IV GP Manager"), as the general partner of Omega IV GP. Otello Stampacchia, Richard Lim and Anne-Mari Paster are all the shareholders and directors of Omega IV GP Manager and have shared voting and investment power over the shares held by Omega IV and, as a result, may each be deemed to beneficially own the reported securities. Otello Stampacchia is also a director of the issuer. Each of the Reporting Persons disclaims beneficial ownership of the reported securities, except to the extent of his, her or its pecuniary interest therein.
F2The Series Seed Preferred Stock ("Series Seed") converted automatically into shares of the issuer's common stock on a 1-for-9.94688 basis upon the completion of the issuer's public offering of common stock pursuant the issuer's registration statement under the Securities Act of 1933, as amended, filed with the Commission on June 22, 2018, as subsequently amended (the "IPO"). The Series Seed had no expiration date.
F3The Series A Convertible Preferred Stock ("Series A") converted automatically into shares of the issuer's common stock on a 1-for-9.94688 basis upon the completion of IPO. The Series A had no expiration date.
F4The Series B Convertible Preferred Stock ("Series B") converted automatically into shares of the issuer's common stock on a 1-for-9.94688 basis upon the completion of IPO. The Series B had no expiration date.
F5The Series Seed Warrants (the "Seed Warrants") converted automatically in warrants to purchase shares of the issuer's common stock (the "Common Stock Warrants") on a 1-for-9.94688 basis upon the completion of IPO. The exercise price of the Common Stock Warrants is $1.01 per share of the issuer's common stock. The Seed Warrants had no expiration date and the Common Stock Warrants have no expiration date.
F6The Common Stock Options (the "Options") were granted to Otello Stampacchia in his capacity as a director of the issuer on July 19, 2018 (the "Grant Date") contingent upon the closing of the IPO, with 25% of the Options vesting on the first anniversary of the Grant Date and an additional 3.125% of the Options vesting each month thereafter for 24 months. The Options expire on the tenth anniversary of the Grant Date.