Mereo Biopharma Plunges 35.37% on Phase 3 Study Concerns

On July 10, 2025, Mereo Biopharma's stock experienced a significant drop of 35.37% in pre-market trading.

Mereo Biopharma, in collaboration with Ultragenyx Pharmaceutical Inc., has announced that the Phase 3 Orbit study for setrusumab, targeting multiple subtypes of osteogenesis imperfecta (OI), is progressing to its final analysis. This decision follows the continuation of dosing in the ongoing Phase 3 Orbit and Cosmic clinical studies, with final analyses to be conducted after patients have completed their treatment periods.

This development is part of a comprehensive late-stage program aimed at addressing various subtypes of OI. The continuation of the Phase 3 trial indicates that the companies are committed to gathering more data to support the potential approval of setrusumab. However, the market's reaction suggests that investors may be concerned about the potential outcomes of the final analysis, leading to the significant pre-market drop in Mereo Biopharma's stock price.