Mereo Biopharma Group Plc Class Action Lawsuit – MREO

According to the complaint, defendants provided overwhelmingly positive statements to investors while, at the same time, disseminating materially false and 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. On December 29, 2025, Mereo issued a press release announcing that neither the ORBIT nor the COSMIC Phase 3 studies achieved statistical significance. The press release indicated that neither study met its primary endpoint of reduction in annualized clinical fracture rate compared to placebo or bisphosphonates, respectively, despite improved bone mineral density. Following this news, the price of Mereo’s ADS declined dramatically. From a closing market price of $2.31 per share on December 26, 2025, Mereo’s ADS price fell to $0.29 per share on December 29, 2025, a decline of more than 87.7%.