Ultragenyx Announces Phase 3 Orbit and Cosmic Results for Setrusumab (UX143) in Osteogenesis Imperfecta

Core Insights - Ultragenyx Pharmaceutical Inc. announced that neither the Phase 3 Orbit nor Cosmic studies for setrusumab (UX143) achieved their primary endpoint of reducing annualized clinical fracture rates compared to placebo or bisphosphonates [2][3] - Both studies did achieve secondary endpoints, showing statistically significant improvements in bone mineral density (BMD) [2][3] - The company plans to implement significant expense reductions in response to the study results [6] Study Results - In the Orbit study, participants showed substantial improvements in BMD compared to placebo, consistent with Phase 2 data, but did not see a corresponding reduction in fracture rates [3][4] - The Cosmic study, involving a younger patient population, indicated meaningful BMD improvements associated with a reduction in fracture rates for setrusumab-treated patients compared to those treated with bisphosphonates, although this reduction did not reach statistical significance [4][8] Company Strategy - Ultragenyx is conducting further analyses on the data from both studies to explore other bone health and clinical endpoints beyond fractures [5] - The company continues to build commercial revenue from four approved products and is preparing for potential near-term gene therapy launches and a pivotal Phase 3 readout in Angelman syndrome [6] Product Information - Setrusumab is a fully human monoclonal antibody that inhibits sclerostin, aimed at increasing new bone formation, BMD, and bone strength in Osteogenesis Imperfecta (OI) [9][10] - OI is a genetic disorder affecting bone metabolism, with no globally approved treatments available, impacting approximately 60,000 individuals in commercially accessible regions [11]