X0306 4 2020-06-08 0 0001420565 AILERON THERAPEUTICS INC ALRN 0001315797 Satter Muneer A C/O SATTER MANAGEMENT CO., L.P., 676 NORTH MICHIGAN AVENUE, SUITE 4000 CHICAGO IL 60611 1 0 1 1 See Remarks Common Stock 2020-06-08 4 P 0 3700000 1.10 A 7609449 I See Footnote Reflects shares that were purchased directly from the underwriter in an underwritten public offering conducted by the Issuer. The amount in Column 4 includes (a) 350,742 shares purchased by various trusts and other entities for which the Reporting Person serves as trustee, investment advisor or manager and, in such capacity, has sole voting and dispositive power over all such shares and (b) 3,349,258 shares purchased by Satter Medical Technology Partners, L.P. ("SMTP") for which the Reporting Person has sole voting and dispositive power over all such shares. The Reporting Person disclaims beneficial ownership of all shares included in clauses (a) and (b) of this footnote (1), except to the extent of his pecuniary interest. The amount in Column 5 includes (a) 161,440 shares that are held by the Muneer A. Satter Revocable Trust for which the Reporting Person serves as trustee and, in such capacity, has sole voting and dispositive power over all such shares, (b) 367,408 shares that are held by various other trusts and other entities for which the Reporting Person serves as trustee, investment advisor or manager and, in such capacity, has sole voting and dispositive power over all such shares, and (c) the remaining balance of shares are held by SMTP for which the Reporting Person has sole voting and dispositive power over all such shares. The Reporting Person disclaims beneficial ownership of all shares included in clauses (b) and (c) of this footnote (2), except to the extent of his pecuniary interest therein. In connection with its original investment, SMTP had a contractual right to designate one member of the Board of Directors of Aileron Therapeutics, Inc. Therefore, the Reporting Person may be deemed to be a director by deputization. /s/ Robert M. Hayward, P.C., attorney-in-fact for Muneer Satter 2020-06-09