Philadelphia, Pennsylvania--(Newsfile Corp. - February 5, 2026) - National plaintiffs' law firm Berger Montague PC announces that a class action lawsuit has been filed against Mereo BioPharma Group plc (NASDAQ: MREO) ("Mereo" or the "Company") on behalf of investors who purchased American Depositary Shares ("ADS") issued by Mereo during the period from June 5, 2023 through December 26, 2025 (the "Class Period").

Investor Deadline: Investors who purchased Mereo securities during the Class Period may, no later than April 6, 2026, seek to be appointed as a lead plaintiff representative of the class. To learn your rights, CLICK HERE.

Mereo is a biopharmaceutical company focused on developing therapies for rare and serious diseases. The Company is headquartered in London, UK.

According to the lawsuit, throughout the Class Period, defendants issued overwhelmingly positive statements to investors concerning the ORBIT and COSMIC Phase 3 programs, clinical trials to test setrusumab as a treatment for Osteogenesis Imperfecta.

When, on December 29, 2025, Mereo disclosed that neither study achieved its primary endpoint of reducing the annualized clinical fracture rate, the price of its ADS dropped more than 87%, from a closing price of $2.31 per share on December 26, 2025 to a close of $0.29 per share on December 29, 2025.

If you are a Mereo investor and would like to learn more about this action, CLICK HERE or please contact Berger Montague: Andrew Abramowitz at aabramowitz@bergermontague.com or (215) 875-3015, or Caitlin Adorni at cadorni@bergermontague.com or (267)764-4865.

About Berger Montague
Berger Montague is one of the nation's preeminent law firms focusing on complex civil litigation, class actions, and mass torts in federal and state courts throughout the United States. With more than $2.4 billion in 2025 post-trial judgments alone, the Firm is a leader in the fields of complex litigation, antitrust, consumer protection, defective products, environmental law, employment law, securities, and whistleblower cases, among many other practice areas. For over 55 years, Berger Montague has played leading roles in precedent-setting cases and has recovered over $50 billion for its clients and the classes they have represented. Berger Montague is headquartered in Philadelphia and has offices in Chicago; Malvern, PA; Minneapolis; San Diego; San Francisco; Toronto, Canada; Washington, D.C., and Wilmington, DE.

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Source: Berger Montague