Mereo BioPharma Group plc (NASDAQ: MREO), a clinical-stage biotech firm focused on rare diseases, shared strategic updates today that underscore its dual therapeutic momentum: the Phase 3 Orbit Study of setrusumab for osteogenesis imperfecta (OI) is slated for a second interim analysis mid-2025, while its oral neutrophil elastase inhibitor alvelestat has earned a positive opinion for EU orphan designation, with a final decision expected in Q1 2025.

Setrusumab (UX143), partnered with Ultragenyx, continues patient dosing in the Orbit Phase 3 study, positioning itself as a potential standard-of-care in OI if the next interim and final analyses confirm promising. Simultaneously, the cosmic open-label Phase 3 study assessing setrusumab versus intravenous bisphosphonate therapy in young children will be assessed in parallel with the Orbit result.

On the alvelestat front, the EMA’s Committee for Orphan Medicinal Products (COMP) has issued a favorable opinion on its orphan designation request. This follows prior U.S. orphan drug and Fast Track designations, and if final EU approval is granted, alvelestat will benefit from incentives including ten-year market exclusivity and reduced regulatory fees.

Mereo’s announcement sends a clear message: their approach combines scientifically driven rare disease therapeutics with regulatory strategy—accelerating clinical programs while maintaining fiscal discipline. With cash reserves expected to eclipse key inflection points through 2027, the company is well-positioned to execute on both the OI and alpha-1 antitrypsin deficiency-associated lung disease (AATD‑LD) fronts, as well as pursue oncology and reproductive medicine partnerships through its diversified portfolio.