Ultragenyx, Mereo Continue Phase 3 UX143 Trials After Safety Review

Ultragenyx Pharmaceutical and Mereo BioPharma announced that their Phase 3 clinical trials for UX143 (setrusumab), a treatment for osteogenesis imperfecta, will continue as planned following a Data Monitoring Committee review confirming the drug's acceptable safety profile. The trials, named Orbit and Cosmic, involve pediatric and young adult patients, with final data expected by the end of the year after at least 18 months of treatment. Despite hopes for an early stop, more data is needed to confirm efficacy, which caused Ultragenyx and Mereo BioPharma stocks to drop significantly in after-hours trading. The drug shows promise in increasing bone mass and reducing fractures, addressing a high unmet medical need, as no globally approved treatments for the condition currently exist. From a financial perspective, while the continuation of the trials is positive for potential future revenue, risks related to clinical and regulatory challenges remain, with Ultragenyx aiming for profitability by 2027 amid current negative cash flows. Analyst sentiment on Ultragenyx remains cautiously optimistic, reflecting strong revenue growth and clinical progress but tempered by valuation and profitability concerns.