X0306 4 2022-11-18 0001267565 COLLEGIUM PHARMACEUTICAL, INC COLL 0001443841 Ciaffoni Joseph C/O COLLEGIUM PHARMACEUTICAL, INC. 100 TECHNOLOGY CENTER DRIVE STOUGHTON MA 02072 1 1 0 0 President and CEO Common Stock 2022-11-18 4 M 0 1989 15.9 A 325442 D Common Stock 2022-11-18 4 S 0 1989 22.02 D 323453 D Stock Option (Right to Purchase) 15.9 2022-11-18 4 M 0 1989 0 D 2029-01-25 Common Stock 1989 0 D The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on August 25, 2022. The price reported in column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $22.00 to $22.07, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the U.S. Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (2). All of the 1,989 option shares are exercisable. /s/ Colleen Tupper as Attorney-In-Fact For Joseph Ciaffoni 2022-11-22