Robbins LLP is Investigating Allegations that Mereo BioPharma Group plc (MREO) Misled Investors Regarding Phase 3 Orbit and Cosmic Studies for Setrusumab  

Robbins LLP informs stockholders that a class action was filed on behalf of all investors who purchased or otherwise acquired Mereo BioPharma Group plc. (NASDAQ: MREO) American Depository Shares ("ADS") between June 5, 2023 and December 26, 2025. Mereo is a biopharmaceutical company focused on the development of therapeutics for rare diseases.

The Allegations

According to the complaint, defendants provided investors with material information concerning their expected results for the Phase 3 ORBIT and COSMIC studies for setrusumab in Osteogenesis Imperfecta (OI). Defendants’ statements included, among other things, confidence in setrusumab’s ability to ultimately reduce the annualized fracture rates of the tested patients and in the study itself to put setrusumab in an opportunity to succeed in reaching statistical significance of this key endpoint. The complaint continues that defendants provided these positive statements to investors while, at the same time, disseminating false and materially misleading statements and/or concealing material adverse facts concerning the true state of the Phase 3 ORBIT and COSMIC programs; neither of which hit its primary endpoints of reducing annualized clinical fracture rate compared to the placebo or bisphosphonate control groups, respectively. Such statements absent these material facts caused Plaintiff and other shareholders to purchase Mereo’s ADS at artificially inflated prices.

The complaint alleges that on December 29, 2025, Mereo issued a press release announcing that neither the ORBIT nor the COSMIC Phase 3 studies met its primary endpoint of reduction in annualized clinical fracture rate (“AFR”) compared to placebo or bisphosphonates, respectively, despite improved bone mineral density (“BMD”).  On this news, the price of Mereo’s ADS declined from $2.31 per share on December 26, 2025, to $0.29 per share on December 29, 2025, a decline of more than 87.7%.

What Now: You may be eligible to participate in the class action against Mereo BioPharma Group plc. Shareholders who wish to serve as lead plaintiff for the class should contact Robbins LLP. The lead plaintiff is a representative party who acts on behalf of other class members in directing the litigation.  You do not have to participate in the case to be eligible for a recovery. If you choose to take no action, you can remain an absent class member.

All representation is on a contingency fee basis. Shareholders pay no fees or expenses.