Security	Conv. / exercise price	Date	Code	Shares	A/D	Exercisable	Expires	Underlying	Underlying shares	Owned after	D/I
Common Stock Warrant^F2,F3,F1	$14.004	Jan 16, 2015	J	249,932	D	Feb 14, 2014	Feb 14, 2019	Common Stock	249,932	0	D
Common Stock Warrant^F4,F5,F1	$14.004	Jan 16, 2015	J	121,396	D	Feb 14, 2014	Feb 14, 2019	Common Stock	121,396	0	I

Explanation of responses

F1The Form 4 filed on January 16, 2015 incorrectly stated the exercise price of the Common Stock Warrant as $2.694. This amendment is being filed to correct the exercise price.
F2Reflects a liquidating pro rata distribution by F2 Bioscience IV L.P. ("F2 IV") to its limited and general partners.
F3The reported securities are owned directly by F2 IV. F2 Bioscience IV GP Ltd. ("F2 IV GP") is the General Partner of F2 IV. Katherine Priestley and Globeways Holdings Limited ("Globeways") are members of F2 IV GP. F2 Capital Limited ("F2 Capital") is an investment adviser to F2 IV. Each of the reporting persons disclaims beneficial ownership of the securities reported herein except to the extent of their pecuniary interest therein, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of all of the reported shares for purposes of Section 16 or for any other purpose.
F4Reflects a liquidating pro rata distribution by F2 Bio Ventures V L.P. ("F2 Bio") to its limited and general partners.
F5The reported securities are owned directly by F2 Bio. F2 Bio Ventures GP Ltd. is the General Partner of F2 Bio. Globeways is the sole member of F2 Bio Ventures GP Ltd. F2 Capital is an investment adviser to F2 Bio. Each of the reporting persons disclaims beneficial ownership of the securities reported herein except to the extent of their pecuniary interest therein, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of all of the reported shares for purposes of Section 16 or for any other purpose.