X0306 4 2017-07-05 0 0001420565 AILERON THERAPEUTICS INC ALRN 0001709690 Ambros Reinhard J. C/O NOVARTIS INTERNATIONAL AG WSJ-200.220 BASEL V8 CH-4002 SWITZERLAND 1 0 0 0 Common Stock 2017-07-05 4 C 0 2277515 A 2277515 I See Footnote Common Stock 2017-07-05 4 P 0 266667 15.00 A 2544182 I See Footnote Series C Preferred Stock 2017-07-05 4 C 0 2967025 0.00 D Common Stock 298583 0 I See Footnote Series C-2 Preferred Stock 2017-07-05 4 C 0 4238607 0.00 D Common Stock 426547 0 I See Footnote Series D Preferred Stock 2017-07-05 4 C 0 6781770 0.00 D Common Stock 682476 0 I See Footnote Series E-2 Preferred Stock 2017-07-05 4 C 0 2644558 0.00 D Common Stock 266132 0 I See Footnote Series E-3 Preferred Stock 2017-07-05 4 C 0 2293829 0.00 D Common Stock 230837 0 I See Footnote Series F Preferred Stock 2017-07-05 4 C 0 3705882 0.00 D Common Stock 372937 0 I See Footnote The Series C, Series C-2, 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 C, Series C-2, 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. The shares are directly owned by Novartis Bioventures Ltd. Novartis Bioventures Ltd. is a wholly-owned indirect subsidiary of Novartis AG, which is an indirect beneficial owner of the reported securities. The board of directors of Novartis Bioventures Ltd. has sole voting and investment power over such shares. None of the members of its board of directors has individual voting or investment power with respect to such shares and each disclaims beneficial ownership of such shares. The Reporting Person is an employee of a corporation that is affiliated with Novartis Bioventures Ltd., a position from which he will retire effective September 1, 2017. Dr. Ambros disclaims beneficial ownership of the shares held by Novartis Bioventures Ltd., except to the extent of his pecuniary interest arising as a result of his employment by such affiliate of Novartis Bioventures Ltd. Novartis Bioventures Ltd., a wholly-owned indirect subsidiary of Novartis AG, acquired 266,667 shares of Common Stock in the Issuer's initial public offering. Exhibit Index: 24.1 Power of Attorney /s/ Kira A. Nelson, attorney-in-fact for Reinhard J. Ambros 2017-07-05