INVESTOR ALERT: Ultragenyx Pharmaceutical Inc. Investors with Substantial Losses Have Opportunity to Lead Class Action Lawsuit - RARE

Core Viewpoint - The Ultragenyx Pharmaceutical Inc. is facing a class action lawsuit due to alleged violations of the Securities Exchange Act of 1934, with claims that the company and its executives made misleading statements regarding the efficacy of their drug setrusumab for treating Osteogenesis Imperfecta [1][3]. Group 1: Class Action Details - The class action lawsuit is titled Bailey v. Ultragenyx Pharmaceutical Inc., and it includes purchasers of Ultragenyx common stock from August 3, 2023, to December 26, 2025 [1]. - Investors have until April 6, 2026, to seek appointment as lead plaintiff in the lawsuit [1][6]. - The lawsuit alleges that Ultragenyx misrepresented the reliability of data from its Phase III Orbit study, which failed to show a statistically significant reduction in annualized fracture rate [3]. Group 2: Allegations and Stock Impact - On July 9, 2025, Ultragenyx disclosed that the Phase III Orbit study did not achieve statistical significance, leading to a stock price drop of over 25% [4]. - Following a December 29, 2025 announcement that both the Phase III Orbit and Cosmic studies failed to meet primary endpoints, Ultragenyx's stock fell more than 42% [5]. - The company attributed the study failures to a low fracture rate in the placebo group and a trend that did not reach statistical significance [5]. Group 3: Legal Process and Firm Background - The Private Securities Litigation Reform Act of 1995 allows any investor who purchased Ultragenyx stock during the class period to seek lead plaintiff status [6]. - Robbins Geller Rudman & Dowd LLP, the law firm handling the case, is recognized as a leading firm in securities fraud litigation, having recovered over $916 million for investors in 2025 alone [7].