X0206 3 2017-06-28 0 0001420565 AILERON THERAPEUTICS INC ALRN 0001553255 Apple Tree Partners II - Annex, L.P. 47 HULFISH STREET SUITE 441 PRINCETON NJ 08542 0 0 1 0 Series E Preferred Stock Common Stock 351186 D Series E-1 Preferred Stock Common Stock 304611 D The Series E Preferred Stock is convertible into Common Stock on a 9.937-for-one basis into the number of shares of Common Stock shown in column 3 at any time at the holder's election and automatically upon the closing of the Issuer's initial public offering. The shares have no expiration date. The Series E-1 Preferred Stock is convertible into Common Stock on a 9.937-for-one basis into the number of shares of Common Stock shown in column 3 at any time at the holder's election and automatically upon the closing of the Issuer's initial public offering. The shares have no expiration date. Dr. Seth L. Harrison is a principal of the general partner of Apple Tree Partners II-Annex, L.P., and Dr. Harrison disclaims beneficial ownership of the shares held by Apple Tree Partners II-Annex, L.P., except to the extent of his pecuniary interest therein. Dr. Harrison has sole voting and investment power over the shares held by Apple Tree Partners II-Annex, L.P. /s/ Dr. Seth L. Harrison 2017-06-28