Law Firms Seek Ultragenyx Investors to Lead Securities Class Actions After OI Trial Miss

Overview

• Two shareholder firms announced class actions against Ultragenyx and invited RARE investors to seek lead-plaintiff roles before the April 6, 2026 deadline.
• Eligible investors are those who bought Ultragenyx shares between August 3, 2023 and December 26, 2025.
• The complaints say the company misled investors about its Osteogenesis Imperfecta drug after the Phase III ORBIT study failed to show a statistically significant drop in fracture rates.
• The suits cite federal securities fraud laws, including Exchange Act Sections 10(b) and 20(a) and SEC Rule 10b-5.
• The class is not certified yet, and the upcoming lead-plaintiff decision will determine who directs the litigation and selects counsel under the PSLRA framework.