Mereo Biopharma Group (MREO) Leerink’s Global Healthcare Conference 2025 summary

Setrusumab program updates

• Phase III for osteogenesis imperfecta is fully enrolled, with first interim analysis completed and second interim analysis expected mid-year.

• Interim analyses are designed to allow early access for placebo patients and potentially accelerate filing if efficacy is overwhelming.

• Interim 2 analysis will have patients with at least 12 months' treatment, using a less stringent alpha than interim 1, increasing the chance to demonstrate efficacy.

• Variability between arms is a key unknown; not meeting the p-value does not necessarily mean lack of efficacy.

• If interim 2 is not met, the final 18-month analysis will occur in Q4, with most statistical power reserved for this endpoint.

Clinical rationale and trial design

• Setrusumab builds bone and inhibits resorption, showing significant improvements in bone strength and reduction in fractures, even with underlying collagen defects.

• Profound improvements in mobility were observed in phase II, supporting the therapy's impact beyond fracture reduction.

• Orbit study (ages 5–25) compares setrusumab to placebo, with many patients previously on bisphosphonates; Cosmic study (ages 2–6) compares to bisphosphonates for safety and numerical efficacy.

• Baseline fracture rates are higher in Cosmic, potentially increasing power for detecting differences.

• Orbit is considered the main study for regulatory purposes, focusing on setrusumab's effect versus placebo.

Market preparation and access strategy

• Identified 5,000 pediatric and 5,000 adult eligible patients in key EU5 countries, with expansion to Benelux and Scandinavia.

• Patient care is concentrated in a small number of expert centers, enabling efficient field force deployment.

• Engaged with NICE and G-BA for pricing and reimbursement groundwork; collecting real-world evidence and patient impact data through IMPACT and SATURN programs.

• Longitudinal bisphosphonate data from Italian centers is being analyzed for publication and payer discussions.