Washington, D.C. 20549


Pursuant to Section 13 OR 15 (d)
of the Securities Exchange Act of 1934
Date of Report (Date of earliest event reported): July 31, 2020

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Item 8.01 – Other Events.

On July 31, 2020, Sesen Bio, Inc. (the “Company”) successfully completed the final of three commercial-scale drug substance cGMP process performance qualification (“PPQ”) manufacturing runs for Vicineum™, the Company's lead product candidate, with its contract manufacturing organization partner, FUJIFILM Diosynth Biotechnologies U.S.A., Inc. (“Fujifilm”). As previously disclosed, the Company has partnered with Fujifilm and Baxter Oncology GmbH (“Baxter”) for the manufacturing process and technology transfer of Vicineum.
On August 4, 2020, the Company completed validation studies for the drug substance PPQ batches. The Company also received the interim certificate of analysis to ship drug substance to Baxter to complete the next drug product PPQ run. Based on this progress, the Company expects to complete the manufacturing of the full drug product PPQ campaign for Vicineum in late-September 2020.
The analytical comparability and stability data from the PPQ campaigns for drug substance and drug product are the last material deliverables for the Company to complete its Biologics License Application (“BLA”) submission for Vicineum to the United States Food and Drug Administration in the fourth quarter of 2020.


This Current Report on Form 8-K contains forward-looking statements, including, but not limited to, statements related to expectations regarding the timing of completion of the Company’s BLA submission for Vicineum and expectations regarding the timing of shipment of the bulk drug substance to Baxter and the manufacture of the remaining drug product PPQ batches. These forward-looking statements are based on the Company’s current expectations and inherently involve significant risks and uncertainties. The Company’s actual results and the timing of events could differ materially from those anticipated in such forward-looking statements as a result of these risks and uncertainties. A further description of the risks and uncertainties relating to the business of the Company is contained in the Company’s most recent annual report on Form 10-K and the Company’s quarterly reports on Form 10-Q, as well as any amendments thereto reflected in subsequent filings with the SEC. The Company undertakes no duty or obligation to update any forward-looking statements contained in this report as a result of new information, future events or changes in its expectations.

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.
Date: August 7, 2020
Sesen Bio, Inc.
/s/ Thomas R. Cannell, D.V.M.

Thomas R. Cannell, D.V.M.

President and Chief Executive Officer