X0306 4 2019-09-12 0 0001420565 AILERON THERAPEUTICS INC ALRN 0001007706 VON RICKENBACH JOSEF H C/O AILERON THERAPEUTICS, INC. 490 ARSENAL WAY, SUITE 210 WATERTOWN MA 02472 1 0 0 0 Common Stock 2019-09-12 4 P 0 88145 0.9785 A 193188 D Common Stock 2019-09-13 4 P 0 25000 0.9702 A 218188 D The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $0.8608 per share to $1.05 per share, inclusive. The Reporting Person undertakes to provide the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $0.9360 per share to $0.99 per share, inclusive. The Reporting Person undertakes to provide the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. /s/ Richard J. Wanstall, attorney-in-fact for Josef H. von Rickenbach 2019-09-16