Ultragenyx Investors Seek Lead Plaintiff Role in Class Action Lawsuit

Robbins Geller Rudman & Dowd LLP announces opportunity for investors with substantial losses to lead case against Ultragenyx Pharmaceutical Inc.

Published on Feb. 14, 2026

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Investors who purchased Ultragenyx Pharmaceutical Inc. (NASDAQ: RARE) common stock between August 3, 2023 and December 26, 2025 have until April 6, 2026 to seek appointment as lead plaintiff in a class action lawsuit against the company and certain executives. The lawsuit alleges Ultragenyx misled investors about the potential success of its Phase 3 study for the drug setrusumab in reducing fracture rates for patients with Osteogenesis Imperfecta.

Why it matters

Ultragenyx is a biopharmaceutical company focused on rare and ultra-rare genetic diseases, and the failure of its Phase 3 studies for setrusumab could have significant financial and reputational impacts. The class action lawsuit aims to recover losses for investors who were allegedly misled about the drug's prospects.

The details

The class action lawsuit, captioned Bailey v. Ultragenyx Pharmaceutical Inc., alleges that Ultragenyx and its executives made false and/or misleading statements about the effects of setrusumab on Osteogenesis Imperfecta patients and minimized the risk that the Phase 3 Orbit study would fail to achieve a statistically significant reduction in annualized fracture rate. The lawsuit claims Ultragenyx's optimism about the Orbit study results was misplaced because the Phase 2 results had no placebo control group for appropriate comparison. The lawsuit further alleges that when Ultragenyx later revealed the Phase 3 Orbit and Cosmic studies had failed to achieve statistical significance, the company's stock price dropped significantly.

  • On July 9, 2025, Ultragenyx revealed the Phase 3 Orbit study failed to achieve statistical significance for the second interim analysis.
  • On December 29, 2025, Ultragenyx announced both the Phase 3 Orbit and Cosmic studies had not achieved statistical significance against the primary endpoints.

The players

Ultragenyx Pharmaceutical Inc.

A biopharmaceutical company that focuses on the identification, acquisition, development, and commercialization of novel products for the treatment of rare and ultra-rare genetic diseases.

Robbins Geller Rudman & Dowd LLP

A law firm representing the plaintiffs in the class action lawsuit against Ultragenyx.

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What they’re saying

“If you suffered substantial losses and wish to serve as lead plaintiff of the Ultragenyx class action lawsuit, please provide your information here:”

— J.C. Sanchez, Attorney, Robbins Geller Rudman & Dowd LLP (https://www.rgrdlaw.com/cases-ultragenyx-pharmaceutical-inc-class-action-lawsuit-rare.html)

What’s next

The judge in the case will decide on April 6, 2026 whether to allow investors to serve as the lead plaintiff in the class action lawsuit against Ultragenyx.

The takeaway

This case highlights the importance of transparency and accurate disclosures from pharmaceutical companies, especially those focused on rare diseases, in order to maintain investor trust and protect shareholder value.