X0306 4 2017-07-05 0 0001420565 AILERON THERAPEUTICS INC ALRN 0001143789 APPLE TREE PARTNERS II LP 230 PARK AVENUE, SUITE 2800 NEW YORK NY 10169 0 0 1 0 Common Stock 2017-07-05 4 C 0 18771 A 19022 D Common Stock 2017-07-05 4 C 0 1780564 A 1799586 D Series A Preferred Stock 2017-07-05 4 C 0 1250000 0.00 D Common Stock 12579 0 D Series A-1 Preferred Stock 2017-07-05 4 C 0 615384 0.00 D Common Stock 6192 0 D Series B Preferred Stock 2017-07-05 4 C 0 3706056 0.00 D Common Stock 372955 0 D Series C-1 Preferred Stock 2017-07-05 4 C 0 2967025 0.00 D Common Stock 298583 0 D Series C-2 Preferred Stock 2017-07-05 4 C 0 4238607 0.00 D Common Stock 426547 0 D Series D Preferred Stock 2017-07-05 4 C 0 6781770 0.00 D Common Stock 682476 0 D The Series A and Series A-1 Preferred Stock converted into Common Stock on a 99.37-for-one basis upon the closing of the Issuer's initial public offering without payment of consideration. The Series A and A-1 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. The Series B, Series C-1, Series C-2 and Series D Preferred Stock converted into Common Stock on a 9.937-for-one-basis upon the closing of the Issuer's initial public offering without payment of consideration. The Series B, Series C-1, Series C-2 and Series D 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. Dr. Seth L. Harrison is a principal of the general partner of Apple Tree Partners II, L.P., and Dr. Harrison disclaims beneficial ownership of the shares held by Apple Tree Partners II, 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, L.P. By: Apple Tree Ventures II, L.P., By: Seth L. Harrison, General Partner, /s/ Seth L. Harrison 2017-07-07