Robbins LLP Reminds Investors of Mereo BioPharma Group plc Class Action Deadline

Law firm alerts shareholders to lead plaintiff deadline in lawsuit against biopharmaceutical company.

Published on Feb. 9, 2026

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Robbins LLP has filed a class action lawsuit on behalf of investors who purchased Mereo BioPharma Group plc (NASDAQ: MREO) American Depository Shares (ADS) between June 5, 2023 and December 26, 2025. The lawsuit alleges that Mereo misled investors about the results of its Phase 3 ORBIT and COSMIC studies for its drug setrusumab, which failed to meet primary endpoints.

Why it matters

The lawsuit alleges that Mereo provided investors with overly optimistic information about the prospects for setrusumab, causing shareholders to purchase the company's ADS at artificially inflated prices. The failure of the Phase 3 trials led to an 87.7% drop in Mereo's stock price, resulting in significant losses for investors.

The details

According to the complaint, Mereo told investors that it was confident setrusumab would reduce annualized fracture rates in patients with Osteogenesis Imperfecta (OI), but failed to disclose that neither the ORBIT nor COSMIC Phase 3 studies met their primary endpoints of reducing annualized clinical fracture rates compared to placebo or bisphosphonate control groups, respectively.

  • The class action was filed on behalf of investors who purchased Mereo BioPharma Group plc ADS between June 5, 2023 and December 26, 2025.
  • On December 29, 2025, Mereo announced that neither the ORBIT nor COSMIC Phase 3 studies met their primary endpoints.
  • The lead plaintiff deadline for the class action is April 6, 2026.

The players

Mereo BioPharma Group plc

A biopharmaceutical company focused on the development of therapeutics for rare diseases.

Robbins LLP

A law firm representing the plaintiffs in the class action lawsuit against Mereo BioPharma Group plc.

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What’s next

The lead plaintiff deadline for the class action is April 6, 2026. Shareholders who wish to serve as lead plaintiff for the class must submit their papers to the court by this date.

The takeaway

This case highlights the importance of transparency and accurate disclosure from biopharmaceutical companies, as investors rely on this information to make informed decisions. The significant drop in Mereo's stock price following the failed Phase 3 trials underscores the potential consequences for companies that allegedly mislead investors.