RARE, MREO Tank as Osteogenesis Study Fails to Meet Primary Endpoint

Core Insights - Shares of Ultragenyx Pharmaceutical (RARE) and Mereo BioPharma (MREO) fell significantly by 42.3% and 87.6% respectively after disappointing results from phase III studies evaluating setrusumab for osteogenesis imperfecta treatment [1][2] Study Results - The Orbit and Cosmic studies did not achieve statistical significance for their primary endpoints related to annualized clinical fracture rate compared to placebo or bisphosphonates [2][7] - Both studies showed statistically significant improvements in bone mineral density (BMD) as a secondary endpoint, with no changes in safety profiles [2][9] - In the Orbit study, participants had meaningful BMD improvements, but these did not lead to a reduction in fracture rates [9] - The Cosmic study indicated that while BMD improvements were observed in a younger patient population, the reduction in fracture rates compared to bisphosphonates was not statistically significant [10] Company Actions - Ultragenyx is reviewing its operations and will implement significant cost-reduction measures following the study results [3][7] - The company is conducting additional analyses on the data from both studies to explore other bone health and clinical endpoints beyond fractures [10] Stock Performance - Over the past six months, Ultragenyx shares have declined by 45.7%, while Mereo BioPharma shares have dropped by 89.7%, contrasting with a 25.9% increase in the industry [4]