Replimune (REPL) Faces Investor Lawsuit Following 77% Stock Crash After FDA Rejects Key Drug - Hagens Berman

SAN FRANCISCO, Aug. 25, 2025 (GLOBE NEWSWIRE) -- Hagens Berman is investigating claims alleged in a new securities class action against Replimune Group, Inc. (NASDAQ: REPL) and its executives after the company's stock plummeted following the FDA’s rejection of its leading cancer drug, RP1. The lawsuit alleges that Replimune misled investors by overstating the drug’s trial data and failing to disclose critical regulatory risks.

The filing, known as Jboor v. Replimune Group, Inc., et al., is on behalf of investors who bought Replimune securities between November 22, 2024, and July 21, 2025.

Hagens Berman urges Replimune investors who suffered substantial losses to submit your losses now.

Class Period: Nov. 22, 2024 – July 21, 2025
Lead Plaintiff Deadline: Sept. 22, 2025
Visit: www.hbsslaw.com/investor-fraud/repl
Contact the Firm Now: REPL@hbsslaw.com
                                         844-916-0895

The FDA’s Complete Response Letter and the Market’s Reaction

On July 22, 2025, Replimune publicly announced that the U.S. Food and Drug Administration (FDA) had issued a “Complete Response Letter” (CRL) for its Biologics License Application (BLA) for RP1. This letter effectively halted the approval process for the investigational drug, which was intended to treat advanced melanoma.

The news triggered a massive sell-off, causing Replimune's stock to plummet by 77% in a single day, wiping out billions in market value.

Allegations of Misleading Statements and Undisclosed Risks

The complaint alleges that throughout the Class Period, Replimune gave investors a false sense of security. The company highlighted the FDA’s prior Breakthrough Therapy and Accelerated Approval designations and touted “durable response” data from its IGNYTE trial, which served as the basis for its application.
According to the lawsuit, these statements were misleading because Replimune allegedly failed to disclose that:

• The company had overstated the likelihood of success for the IGNYTE trial.
  
  
• The FDA was likely to find the trial's design and data inadequate for approval.
  
  

The lawsuit points to the CRL itself as evidence, in which the FDA stated that the IGNYTE trial was not “a sufficiently well-designed or controlled investigation to provide substantial evidence of effectiveness.”

Why the FDA Rejected RP1

The FDA's rejection was rooted in specific issues with the IGNYTE trial's methodology that were not previously disclosed to the public, including:

• Patient Heterogeneity: The FDA found the patient population in the study to be too varied, making it difficult to draw reliable conclusions about the drug’s effectiveness.
• Confirmatory Trial Flaws: The agency also flagged issues with the design of the planned confirmatory trial, specifically questioning how the individual contributions of each drug in the combination therapy could be properly evaluated.
  
  

These previously undisclosed regulatory concerns led directly to the stock's dramatic collapse, resulting in significant losses for investors. While the FDA did not raise safety concerns, the CRL has effectively stalled RP1’s path to market.

Hagens Berman’s Investigation

Shareholder rights law firm Hagens Berman is actively investigating whether Replimune misled its investors.

“When a company’s valuation hinges on a single trial, the transparency around that trial’s data and design is paramount. Our investigation is focused on whether Replimune’s investors were misled about the FDA’s concerns.”

If you invested in Replimune and have substantial losses, or have knowledge that may assist the firm’s investigation, submit your losses now »

If you’d like more information and answers to frequently asked questions about the Replimune case and our investigation, read more »

Whistleblowers: Persons with non-public information regarding Replimune should consider their options to help in the investigation or take advantage of the SEC Whistleblower program. Under the new program, whistleblowers who provide original information may receive rewards totaling up to 30 percent of any successful recovery made by the SEC. For more information, call Reed Kathrein at 844-916-0895 or email REPL@hbsslaw.com.

About Hagens Berman
Hagens Berman is a global plaintiffs’ rights complex litigation firm focusing on corporate accountability. The firm is home to a robust practice and represents investors as well as whistleblowers, workers, consumers and others in cases achieving real results for those harmed by corporate negligence and other wrongdoings. Hagens Berman’s team has secured more than $2.9 billion in this area of law. More about the firm and its successes can be found at hbsslaw.com. Follow the firm for updates and news at @ClassActionLaw.  

Contact:
Reed Kathrein, 844-916-0895

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