Kirby McInerney LLP | Financial Litigation Law Firm | Sesen Bio, Inc.
This links to the home page

Sesen Bio, Inc.

The law firm of Kirby McInerney LLP announces 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 patients with cancer. The Company’s most advanced product candidate is Vicinieum, 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 for its bladder cancer treatment Vicineum 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%, 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. As a result, the Company expected that it could not resubmit its BLA until 2023. On this news, the Company’s share price declined by $0.89 per share, or approximately 42%, 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. On this news, the Company’s share price declined by $0.20 per share, or 13%, to close at $1.31 per share on August 18, 2021.
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, or by filling out this contact form, to discuss your rights or interests with respect to these matters without any cost to you.  

Sesen Bio, Inc. Investor Contact Form