Certain Common Stock of SELLAS Life Sciences Group, Inc. are subject to a Lock-Up Agreement Ending on 19-MAY-2024. These Common Stock will be under lockup for 61 days starting from 19-MAR-2024 to 19-MAY-2024.

Details:
The directors and officers have entered into lock-up agreements. Under these agreements, these individuals have agreed, subject to specified exceptions, not to sell or transfer any shares of common stock or securities convertible into, or exchangeable or exercisable for, common stock during a period ending 60 days after the date of this prospectus supplement, without first obtaining the written consent of the purchaser party to the securities purchase agreement.