Mereo BioPharma Sued Over Failed Trial That Caused 87.7% Plunge

Edgen Stock

·Mar 30 2026, 07:51

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Key Takeaways

Mereo BioPharma Group plc is facing a class-action lawsuit for securities fraud after its lead drug candidate, setrusumab, failed to meet its primary goals in late-stage clinical trials. The subsequent stock collapse has prompted legal action on behalf of investors who purchased shares during a period when the company is alleged to have made misleadingly positive statements.

A securities class-action lawsuit has been filed against Mereo BioPharma, alleging the company misled investors about the prospects of its Phase 3 drug trials for setrusumab.
The company announced on December 29, 2025, that two key studies, ORBIT and COSMIC, failed to meet their primary endpoints for treating Osteogenesis Imperfecta.
Mereo's stock collapsed 87.7% on the news, falling from $2.31 to $0.29 per share, erasing significant shareholder value and triggering the legal fallout.

Trial Failure Wipes Out 87.7% of Stock Value

Mereo BioPharma's American Depository Shares (NASDAQ: MREO) collapsed by 87.7% after the company announced disappointing clinical trial results on December 29, 2025. The biopharmaceutical firm revealed that its Phase 3 ORBIT and COSMIC studies for setrusumab, a drug for Osteogenesis Imperfecta (OI), failed to meet their primary endpoint. This involved reducing the annualized clinical fracture rate compared to placebo and bisphosphonate control groups. The news sent the stock price plummeting from $2.31 on December 26, 2025, to just $0.29 per share by December 29, 2025, devastating investors.

Following the sharp decline, law firms including The DJS Law Group and Robbins LLP have initiated a class-action lawsuit against Mereo BioPharma. The suit alleges violations of federal securities laws, specifically §§10(b) and 20(a) of the Securities Exchange Act of 1934. The core allegation is that between June 5, 2023, and December 26, 2025, Mereo's management made materially false and misleadingly positive statements about setrusumab's potential for success. The complaint contends that the company concealed adverse facts about the trials, causing investors to purchase shares at artificially inflated prices before the eventual crash. The legal action seeks to recover damages for shareholders who suffered significant losses.

Trial Failure Wipes Out 87.7% of Stock Value

Lawsuit Alleges Misleading Statements Inflated Share Price