INVESTOR ALERT: Kirby McInerney LLP Reminds Investors That a Class Action Lawsuit Has Been Filed on Behalf of Sesen Bio, Inc. (SESN) Investors and Encourages Investors to Contact the Firm Before October 18, 2021

The law firm of Kirby McInerney LLP reminds investors that a class action lawsuit has been filed in the U.S. District Court for the Southern District of New York on behalf of those who acquired Sesen Bio, Inc. (“Sesen Bio” or the “Company”) (NASDAQ: SESN) securities from December 21, 2020 through August 17, 2021, inclusive (the “Class Period”). Investors have until October 18, 2021 to apply to the Court to be appointed as lead plaintiff in the lawsuit.

Sesen Bio, a late-stage clinical company, focuses on designing, engineering, developing, and commercializing targeted fusion protein therapeutics (“TFPTs”) for the treatment of patients with cancer. The Company’s most advanced product candidate is Vicineum, a locally-administered targeted fusion protein developed as a treatment of BCG-unresponsive non-muscle invasive bladder cancer (“NMIBC”).

On August 13, 2021, Sesen Bio announced that the U.S. Food and Drug Administration (“FDA”) declined to approve its Biologics License Application (“BLA”) for its bladder cancer treatment Vicineum in its current form. The FDA provided certain “recommendations specific to additional clinical/statistical data and analyses in addition to Chemistry, Manufacturing and Controls [(“CMC”)] issues pertaining to a recent pre-approval inspection and product quality.” On this news, the Company’s share price declined by $2.80 per share, or approximately 57%, from $4.91 per share to close at $2.11 per share on August 13, 2021.

Then, on August 16, 2021, Sesen Bio further revealed that “it appears that [the Company] will need to do a clinical trial to provide the additional efficacy and safety data necessary for the FDA to assess the benefit-risk profile, which is the basis for approval.” On this news, the Company’s share price declined by $0.89 per share, or approximately 42.2%, from $2.11 per share to close at $1.22 per share on August 16, 2021.

Then, on August 18, 2021, before the market opened, the health and medicine news site STAT published an article entitled “Sesen Bio trial of cancer drug marked by misconduct and worrisome side effects, documents show.” Citing “hundreds of pages of internal documents” and “three people familiar with the matter,” the article detailed that the clinical trial for Vicineum was “marked by thousands of violations of study rules, damning investigator conduct, and worrying signs of toxicity the company did not publicly disclose.”

The lawsuit alleges throughout the Class Period, Defendants made materially false and/or misleading statements, as well as failed to disclose material adverse facts about the Company’s business, operations, and prospects. Specifically, Defendants failed to disclose to investors: (1) that Sesen Bio’s clinical trial for Vicineum had more than 2,000 violations of trial protocol, including 215 classified as major; (2) that three of Sesen Bio’s clinical investigators were found guilty of serious noncompliance, including back-dating data; (3) that Sesen Bio had submitted the tainted data in connection with the BLA for Vicineum; (4) that Sesen Bio’s clinical trials showed that Vicineum leaked out into the body, leading to side effects including liver failure and liver toxicity, and increasing the risks for fatal, drug-induced liver injury; (5) that, as a result of the foregoing, the Company’s BLA for Vicineum was not likely to be approved; (6) that, as a result of the foregoing, there was a reasonable likelihood that Sesen Bio would be required to conduct additional trials to support the efficacy and safety of Vicineum; and (7) that, as a result of the foregoing, Defendants’ positive statements about the Company’s business, operations, and prospects were materially misleading and/or lacked a reasonable basis.

If you purchased or otherwise acquired Sesen Bio securities, have information, or would like to learn more about these claims, please contact Thomas W. Elrod of Kirby McInerney LLP at 212-371-6600, by email at investigations@kmllp.com, or by filling out this contact form, to discuss your rights or interests with respect to these matters without any cost to you.

Kirby McInerney LLP is a New York-based plaintiffs’ law firm concentrating in securities, antitrust, whistleblower, and consumer litigation. The firm’s efforts on behalf of shareholders in securities litigation have resulted in recoveries totaling billions of dollars. Additional information about the firm can be found at Kirby McInerney LLP’s website: http://www.kmllp.com.

This press release may be considered Attorney Advertising in some jurisdictions under the applicable law and ethical rules.

View source version on businesswire.com: https://www.businesswire.com/news/home/20210903005451/en/