X0306 4 2018-08-10 0 0001420565 AILERON THERAPEUTICS INC ALRN 0001288231 LONGENECKER JOHN P PHD C/O AILERON THERAPEUTICS, INC. 281 ALBANY STREET CAMBRIDGE MA 02139 0 1 0 0 President and CEO Common Stock 2018-08-10 4 P 0 10000 2.45 A 10000 D The reported price is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $2.40 to $2.48, inclusive. The reporting person undertakes to provide to Aileron Therapeutics, Inc., any security holder of Aileron Therapeutics, Inc., 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/ Donald Dougherty, attorney-in-fact for John P. Longenecker, Ph.D. 2018-08-14