Ultragenyx Pharmaceutical Faces Class Action
A securities fraud class action lawsuit is seeking recovery for investors in Ultragenyx Pharmaceutical Inc. (RARE). The lawsuit covers investors who purchased common stock between August 2023 and December 2025.
The lawsuit alleges that Ultragenyx made misleadingly positive statements about its drug setrusumab, a treatment for the genetic disorder Osteogenesis Imperfecta, also known as brittle bone disease. These statements concerned the Phase III ORBIT and COSMIC studies. Specifically, the complaint claims the company expressed confidence that setrusumab would significantly reduce fracture rates. However, the lawsuit alleges this optimism was unwarranted because it was based on Phase II trial results that lacked a placebo control group for comparison. The core of the allegations is that while the drug did show an increase in bone density, this did not necessarily correlate to a decrease in fractures. The suit argues that the company concealed this material risk from investors, leading to artificially inflated stock prices. On December 29, 2025, Ultragenyx announced that both the ORBIT and COSMIC studies failed to meet their primary endpoints of statistically significant fracture rate reduction. Following the announcement, the company's stock price plummeted by more than 42%. The stock fell from a closing price of $34.19 on December 26, 2025, to $19.72 per share on December 29, 2025. Multiple law firms, including Kessler Topaz Meltzer & Check and Pomerantz LLP, have filed class-action lawsuits. Investors who purchased stock between August 3, 2023, and December 26, 2025, are included in the class period. The deadline for an investor to seek appointment as lead plaintiff is April 6, 2026.
