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Investors With Substantial Losses Have Opportunity to Lead the Sesen Bio, Inc. Class Action Lawsuit – SESN

Robbins Geller Rudman & Dowd LLP announces that purchasers of Sesen Bio, Inc. (NASDAQ: SESN) securities between December 21, 2020 and August 17, 2021, inclusive (the “Class Period”), have until October 18, 2021 to seek appointment as lead plaintiff in the Sesen Bio class action lawsuit. The Sesen Bio class action lawsuit (Bibb v. Sesen Bio, Inc., No. 21-cv-07025) charges Sesen Bio and certain of its top executives with violations of the Securities Exchange Act of 1934. The Sesen Bio class action lawsuit was commenced on August 19, 2021 in the Southern District of New York and is assigned to Judge Alvin K. Hellerstein.

If you wish to serve as lead plaintiff of the Sesen Bio class action lawsuit, please provide your information by clicking here. You can also contact attorney J.C. Sanchez of Robbins Geller by calling 800/449-4900 or via e-mail at Lead plaintiff motions for the Sesen Bio class action lawsuit must be filed with the court no later than October 18, 2021.

CASE ALLEGATIONS: The Sesen Bio class action lawsuit alleges that, throughout the Class Period, defendants made false and misleading statements and failed to disclose that: (i) Sesen Bio’s clinical trial for Vicineum had more than 2,000 violations of trial protocol, including 215 classified as “major”; (ii) 3 of Sesen Bio’s clinical investigators were found guilty of “serious noncompliance,” including “back-dating data”; (iii) Sesen Bio had submitted the tainted data in connection with its Biologics License Application (“BLA”) for Vicineum; (iv) 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; (v) as a result, Sesen Bio’s BLA for Vicineum was not likely to be approved; (vi) consequently, there was a reasonable likelihood that Sesen Bio would be required to conduct additional trials to support the efficacy and safety of Vicineum; and (vii) as such, defendants’ positive statements about Sesen Bio’s business, operations, and prospects were materially misleading and/or lacked a reasonable basis.

On August 13, 2021, Sesen Bio announced that the U.S. Food and Drug Administration (“FDA”) declined to approve its BLA for 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, Sesen Bio’s share price fell approximately 57%.

Then, on August 16, 2021, Sesen Bio further revealed that “it appears that [Sesen Bio] 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, Sesen Bio expected that it could not resubmit its BLA until 2023. On this news, Sesen Bio’s share price fell an additional 42%.

Finally, on August 18, 2021, 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, Sesen Bio’s share price fell an additional 13%, further damaging investors.

THE LEAD PLAINTIFF PROCESS: The Private Securities Litigation Reform Act of 1995 permits any investor who purchased Sesen Bio securities during the Class Period to seek appointment as lead plaintiff in the Sesen Bio class action lawsuit. A lead plaintiff is generally the movant with the greatest financial interest in the relief sought by the putative class who is also typical and adequate of the putative class. A lead plaintiff acts on behalf of all other class members in directing the Sesen Bio class action lawsuit. The lead plaintiff can select a law firm of its choice to litigate the Sesen Bio class action lawsuit. An investor’s ability to share in any potential future recovery of the Sesen Bio action lawsuit is not dependent upon serving as lead plaintiff.

ABOUT ROBBINS GELLER RUDMAN & DOWD LLP: With 200 lawyers in 9 offices nationwide, Robbins Geller Rudman & Dowd LLP is the largest U.S. law firm representing investors in securities class actions. Robbins Geller attorneys have obtained many of the largest shareholder recoveries in history, including the largest securities class action recovery ever – $7.2 billion – in In re Enron Corp. Sec. Litig. The 2020 ISS Securities Class Action Services Top 50 Report ranked Robbins Geller first for recovering $1.6 billion for investors last year, more than double the amount recovered by any other securities plaintiffs’ firm. Please visit for more information.

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Robbins Geller Rudman & Dowd LLP

655 W. Broadway, San Diego, CA 92101

J.C. Sanchez, 800-449-4900

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