Ultragenyx Pharmaceutical(US:RARE) TMX Newsfile·2026-03-31 13:19Core Viewpoint - Faruqi & Faruqi, LLP is investigating potential claims against Ultragenyx Pharmaceutical Inc due to alleged violations of federal securities laws related to misleading statements about the efficacy of its drug setrusumab in treating Osteogenesis Imperfecta [2][4]. Group 1: Allegations and Legal Actions - The complaint alleges that Ultragenyx and its executives misrepresented their knowledge regarding the effects of setrusumab, creating a false impression of reliability while downplaying risks associated with the Phase III Orbit study [4]. - The company reportedly failed to disclose that the optimism surrounding the Phase III Orbit study's results was unfounded, as it relied on Phase II results without a placebo control group, which could have led to misleading conclusions about the drug's effectiveness [4]. - Following the announcement on July 9, 2025, that the Phase III Orbit study did not achieve statistical significance, Ultragenyx's stock price fell by over 25% [5]. Group 2: Study Results and Stock Impact - On December 29, 2025, Ultragenyx disclosed that both the Phase III Orbit and Cosmic studies did not meet primary endpoints for reducing annualized clinical fracture rates compared to placebo or bisphosphonates, attributing the failure to a low fracture rate in the placebo group [6]. - This announcement resulted in a further decline of over 42% in Ultragenyx's stock price [7]. Group 3: Class Action Details - The deadline for investors to seek the role of lead plaintiff in the federal securities class action against Ultragenyx is April 6, 2026 [2]. - The lead plaintiff is defined as the investor with the largest financial interest in the relief sought, who will oversee the litigation on behalf of the class [8].