X0306 4 2022-02-18 0001267565 COLLEGIUM PHARMACEUTICAL, INC COLL 0001746251 Dreyer Scott C/O COLLEGIUM PHARMACEUTICAL, INC. 100 TECHNOLOGY CENTER DRIVE STOUGHTON MA 02072 0 1 0 0 EVP & Chief Commercial Officer Common Stock 2022-02-18 4 S 0 10559 21.61 D 121226 D This Form 4 is being filed late due to an administrative error. The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on May 14, 2021 and amended on September 1, 2021. The price reported in column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $21.22 to $21.93, 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 (3). /s/ Colleen Tupper as Attorney-In-Fact For Scott Dreyer 2022-02-28