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| Collegium Pharmaceutical, Inc.’s Annual Meeting of Shareholders will be held on May 19, 2022 virtually via live webcast www.meetnow.global/MG75KXZ at 8:30 a.m. Eastern Time. Proposals to be voted on at the meeting are listed below along with the Board of Directors’ recommendations. The Board of Directors recommends a vote FOR all the nominees listed and FOR Proposals 2 and 3: 1. Election of Rita Balice-Gordon, Ph.D., Garen Bohlin, John Fallon, M.D., John Freund, M.D., Neil F. McFarlane and Gwen Melincoff as directors to hold office until the 2023 Annual Meeting; Approval of, on an advisory basis, the compensation of the Company’s named executive officers; and Ratification of the appointment of Deloitte & Touche LLP as the Company’s independent registered public accounting firm for the fiscal year ending December 31, 2022. 2. 3. PLEASE NOTE – YOU CANNOT VOTE BY RETURNING THIS NOTICE. To vote your shares you must vote online or request a paper copy of the proxy materials to receive a proxy card. Here’s how to order a copy of the proxy materials and select delivery preferences: Current and future delivery requests can be submitted using the options below. If you request an email copy, you will receive an email with a link to the current meeting materials. PLEASE NOTE: You must use the number in the shaded bar on the reverse side when requesting a copy of the proxy materials. — — — Internet – Go to www.envisionreports.com/COPI. Click Cast Your Vote or Request Materials. Phone – Call us free of charge at 1-866-641-4276. Email – Send an email to investorvote@computershare.com with “Proxy Materials Collegium Pharmaceutical, Inc.” in the subject line. Include your full name and address, plus the number located in the shaded bar on the reverse side, and state that you want a paper copy of the meeting materials. To facilitate timely delivery, all requests for a paper copy of proxy materials must be received by May 9, 2022. Shareholder Meeting Notice |