Sesen Bio Announces Leading Independent Proxy Advisory Firms ISS and Glass Lewis Recommend “FOR” Proposal to Increase Authorized Shares - Seite 2

Since the proposed increase to the number of authorized shares of common stock will not affect the number of shares outstanding, it will not by itself have a dilutive effect on the Company’s current stockholders. Sesen Bio believes this increase will be enough to achieve corporate profitability, and therefore the Company is hopeful this may be the last time it needs to request additional shares.

Sesen Bio’s stockholders are encouraged to vote as ISS and Glass Lewis recommend by voting “FOR” the proposed increase in authorized shares. Voting will be open through the conclusion of the Annual Meeting on May 3, 2021 at 8:00 a.m. EDT. Stockholders with questions about how to vote may contact the Company’s proxy solicitor, Okapi Partners, at [phone] or [e-mail].

Stockholders who have already voted and want to change their vote can update their vote at any time – Sesen Bio will count your vote in accordance with the last instruction received prior to the closing of the polls.

ISS and Glass Lewis are independent proxy advisory firms and do not have any business relationship with Sesen Bio. Sesen Bio did not engage or compensate either firm for their analysis or recommendations.

Where to Find Additional Information

On March 25, 2021, the Company filed a definitive proxy statement with the SEC in connection with the Annual Meeting (such proxy statement and any supplements or amendments thereto, “the Annual Meeting Proxy Materials”). The Annual Meeting Proxy Materials contain important information about the Annual Meeting. Stockholders are urged to read the Annual Meeting Proxy Materials carefully. Stockholders are able to obtain free copies of the Annual Meeting Proxy Materials and other documents filed with the SEC by the Company through the web site maintained by the SEC at www.sec.gov and at https://ir.sesenbio.com/financial-information/sec-filings. The Company, its directors and executive officers may be deemed participants in the solicitation of proxies from stockholders in respect of the Annual Meeting. Detailed information regarding the identity of participants, and their respective interests in the Company by security holdings or otherwise, are set forth in the definitive proxy statement for the Annual Meeting.