Mereo BioPharma Group (MREO) Securities Class Action Lawsuit Investigation

Shamis & Gentile P.A., a law firm that advocates for investors who are victims of securities fraud, is investigating potential claims against Mereo BioPharma Group (MREO).

If you purchased or held Mereo BioPharma securities and suffered losses, you may be eligible to join a class action lawsuit and seek compensation.

About Mereo BioPharma Group

Mereo BioPharma developes and commercializes therapies for rare diseases. The company’s lead asset is setrusumab, a monoclonal antibody being developed for the treatment of osteogenesis imperfecta (OI), a rare genetic bone disorder.

Throughout 2024 and into 2025, Mereo BioPharma partnered with Ultragenyx to advance the Phase 3 Orbit study of setrusumab.

Mereo BioPharma Group raised substantial capital, including a $50 million stock offering in June 2024, to support the continued development and commercialization of this core asset.

Items Under Investigation

Lawyers are investigating whether Mereo BioPharma Group may have made misleading statements or omitted material information regarding the progress and prospects of its Phase 3 Orbit study for setrusumab.

From June 11, 2024 through July 9, 2025, the company consistently issued optimistic updates about the study, emphasizing positive 14-month results, significant reductions in fracture rates, and the absence of serious adverse events. For example, the June 11, 2024 press release highlighted “positive 14-month results” and stated that treatment “significantly reduce[d] fractures” with continued improvement in bone mineral density.

Subsequent quarterly updates reinforced this positive outlook. The Q2 2024 update on Aug. 13, 2024 reported that setrusumab “continued to significantly reduce incidence of fractures” and noted “no treatment-related serious adverse events”, while the Q3 2024 statement on Nov. 12, 2024 celebrated Breakthrough Therapy designation and described the Phase 3 program as “on track” for 2025 topline data. The full-year 2024 report reiterated that the Orbit study was “set to read out” in mid-2025 or Q4 2025, and Q1 2025 results assured investors that the study “remains on track” for an interim mid-2025 or final Q4 analysis.

However, on July 9, 2025, Mereo BioPharma Group and Ultragenyx issued a joint press release revealing that the Orbit trial would only reach a final analysis by year-end, rather than stopping early as previously hoped. The Data Monitoring Committee advised continuing to final analysis, and Ultragenyx CEO Emil Kakkis stated they had “hoped to be able to stop the study early” but now looked forward to year-end results. This announcement implied that the expected interim efficacy had not materialized, which directly contradicted prior market expectations.

The next trading day, July 10, 2025, Mereo BioPharma Group’s American Depositary Receipts (ADRs) fell approximately 42 percent, representing a massive one-day loss in value. There was no broad market event to explain this drop, suggesting the decline was tied directly to the company-specific announcement. Legal professionals may review whether shareholders were adequately informed about the true status of the Orbit trial and if the company’s prior statements were misleading in light of the July 2025 revelation.

Legal professionals might also examine whether company insiders, including CEO Denise Scots-Knight and CFO Christine Fox, had knowledge of any adverse developments in the Orbit study prior to the July 2025 announcement. The fact that Mereo BioPharma Group’s business was heavily dependent on setrusumab’s success, combined with the timing of capital raises, could be relevant to questions about motive and knowledge.

The investigation may focus on whether the company’s repeated positive statements about the Orbit trial’s progress and lack of warnings about potential setbacks were misleading. Lawyers may examine if these statements lacked meaningful caution, especially as investors would expect timely updates given the study’s importance to the company’s future.

Your Rights and Next Steps

This is an active investigation into potential violations of federal securities laws by Mereo BioPharma Group. If lawyers determine that the company made misleading statements or failed to disclose material information, a class action lawsuit may be filed on behalf of affected investors.

Investors who purchased or held Mereo BioPharma Group securities and suffered financial losses may be eligible to participate in any future class action. Joining the investigation does not require any upfront cost, and investors’ rights are protected throughout the process.

It is important for investors to act quickly, as securities investigations are time-sensitive and deadlines may apply. By joining the investigation, investors can help ensure that their interests are represented and that any potential recovery is fairly distributed among those harmed.

You May Be Entitled to Compensation

If you purchased or held Mereo BioPharma Group securities and suffered losses, you may be eligible to join this investigation and seek compensation for your losses. Securities investigations often move quickly, and acting promptly can help protect your rights.

To join the investigation, complete the form below. Lawyers are ready to help investors understand their rights and pursue any available legal remedies.