X0306 4 2017-07-05 1 0001420565 AILERON THERAPEUTICS INC ALRN 0001428044 EXCEL MEDICAL FUND LP 800 BOYLSTON STREET, SUITE 2825 BOSTON MA 02199 0 0 1 0 0001571997 Gullans Steven R. Ph.D. 800 BOYLSTON STREET, SUITE 2825 BOSTON MA 02199 0 0 1 0 0001572066 Blume Frederick R. 800 BOYLSTON STREET, SUITE 2825 BOSTON MA 02199 0 0 1 0 0001572090 Enriquez Juan 800 BOYLSTON STREET, SUITE 2825 BOSTON MA 02199 0 0 1 0 0001571999 Excel Medical Ventures, LLC 800 BOYLSTON STREET, SUITE 2825 BOSTON MA 02199 0 0 1 0 Common Stock 2017-07-05 4 C 0 956100 A 956100 D Common Stock 2017-07-05 4 P 0 60000 15.00 A 1016100 D Series D Preferred Stock 2017-07-05 4 C 0 5934050 0.00 D Common Stock 597167 0 D Series E-2 Preferred Stock 2017-07-05 4 C 0 1329993 0.00 D Common Stock 133842 0 D Series E-3 Preferred Stock 2017-07-05 4 C 0 1153606 0.00 D Common Stock 116091 0 D Series F Preferred Stock 2017-07-05 4 C 0 1083119 0.00 D Common Stock 108998 0 D The Series D, Series E-2, Series E-3 and Series F 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 D, Series E-2, Series E-3 and Series F Preferred Stock were convertible at any time at the holder's election and automatically upon the closing of the Issuer's initial pubic offering. The shares had no expiration date. Excel Medical Ventures, LLC is the general partner of Excel Medical Fund, L.P. Steven R. Gullans, Frederick R. Blume and Juan Enriquez are the Managing Directors of Excel Medical Ventures, LLC. Excel Medical Ventures, LLC and each of these individuals may be deemed to share voting and dispositive power with respect to all shares held by Excel Medical Fund, L.P. Each of the filing persons disclaims beneficial ownership of the shares except to the extent of any pecuniary interest therein. /s/ Frederick R. Blume, Excel Medical Fund, L.P. 2017-07-06 /s/ Steven R. Gullans 2017-07-06 /s/ Frederick R. Blume 2017-07-06 /s/ Juan Enriquez 2017-07-06 /s/ Frederick R. Blume, Excel Medical Ventures, LLC 2017-07-06