Analysts are keeping the faith in Ultragenyx’s brittle bone disease medicines despite the monoclonal antibody failing to score an early outright win in an ongoing phase 3 trial. Ultragenyx and Mereo BioPharma are evaluating UX143, also known as setrusumab, in the phase 3 Orbit study of 159 pediatric and young patients with osteogenesis imperfecta. Source: Fierce Biotech 10/7/2025