On January 25, 2023, Bradley L Radoff announced that he has issued an open letter to the Board of Directors of Sesen Bio, Inc and the Board of Directors of CARISMA Therapeutics Inc. In the letter, Bradley L Radoff reiterated his intention to vote against the proposed merger between the Company and Carisma and rejected the Company?s and Carisma?s apparent attempt to buy Bradley L Radoff? support for the Merger by offering him paid advisory roles in exchange for the vote. Bradley L Radoff stated that he alarmed by such an inappropriate offer, which reinforces his?

view that the Company Board is unfit to serve as fiduciaries and should immediately resign.