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ULTRAGENYX ALERT: Bragar Eagel & Squire, P.C. Announces that a Class Action Lawsuit Has Been Filed Against Ultragenyx Pharmaceutical Inc. and Encourages Investors to Contact the Firm

Key Takeaway: Bragar Eagel & Squire, P.C. has announced a class action lawsuit against Ultragenyx Pharmaceutical Inc., related to losses suffered by investors who purchased shares within a specific period. The lawsuit targets the company's misleading statements regarding the effectiveness of setrusumab in its Phase III studies. It alleges that while Ultragenyx had projected positive outcomes, the studies fell short and did not achieve the desired statistical significance, leading to a substantial drop in stock price. Investors are encouraged to contact the firm for further legal recourse as the case develops.
Price reaction · baseline $24.69 (2026-02-04 close) · hit after-hours · 1 other RARE headline(s) in the window, move may be shared
day 0 close · peak
-3.6%

Market Sentiment Analysis

CONCERNS & RISKS

  • A class action lawsuit has been filed against Ultragenyx Pharmaceutical Inc.
  • Investors are being encouraged to participate due to suffered losses.
  • Ultragenyx's Phase III studies failed to achieve statistical significance.
  • The company's stock price dropped 42.32% in one day following the announcement.

BiopharmaWatch Analysis

From our catalyst data and publicly available data · not financial advice
Best trade, last catalyst
+43%
120-day peak, hindsight
Typical move
2.9%
average across 6 past catalysts
Cash runway
~13 mo
Low dilution risk
Lead asset
BPS804
Phase 2 · Hypophosphatasia

Full Press Release Details

Bragar Eagel & Squire, P.C. Litigation Partner Brandon Walker Encourages Investors Who Suffered Losses In Ultragenyx (RARE) To Contact Him Directly To Discuss Their Options
If you purchased or acquired Ultragenyx common stock between August 3, 2023, to December 26, 2025 and would like to discuss your legal rights, call Bragar Eagel & Squire partner Brandon Walker or Melissa Fortunato directly at (212) 355-4648.
Click here to participate in the action.
NEW YORK, Feb. 05, 2026 (GLOBE NEWSWIRE) --
Bragar Eagel & Squire, P.C., a nationally recognized stockholder rights law firm, announces that a class action lawsuit has been filed against Ultragenyx Pharmaceutical Inc. (“Ultragenyx” or the “Company”) (NASDAQ:RARE) in the United States District Court for the Northern District of California on behalf of all persons and entities who purchased or otherwise acquired Ultragenyx common stock between August 3, 2023, to December 26, 2025, both dates inclusive (the “Class Period”). Investors have until April 6, 2026 to apply to the Court to be appointed as lead plaintiff in the lawsuit.
According to the complaint, during the class period, defendants provided investors with material information concerning Ultragenyx’s expected results for its Phase III Orbit and Cosmic Studies, which tested setrusumab (UX 143) in patients with Osteogenesis Imperfecta (“OI”). Defendants’ statements included, among other things, confidence in setrusumab’s ability to ultimately trigger a decrease in the OI patients’ annualized fracture rate, alongside confidence in the study designs to demonstrate such ability and reduce testing variability that could interfere with such a result.
Plaintiff alleges that defendants provided these overwhelmingly positive statements to investors while, at the same time, disseminating materially false and misleading statements and/or concealing material adverse facts concerning the true state of setrusumab’s potential and the true risk inherent in the study protocols put forth; notably, that, while setrusumab does increase material bone density, this increase does not correlate to a decrease in annualized fracture rates or otherwise the Phase III Orbit and Cosmic studies were much less likely to be able to demonstrate such a link than management claimed. Such statements absent these material facts caused Plaintiff and other shareholders to purchase Ultragenyx’s securities at artificially inflated prices.
The complaint alleges that on December 29, 2025, Ultragenyx announced that both its Phase III Orbit and Cosmic Studies had not “achieved statistical significance against the primary endpoints of reduction in annualized clinical fracture rate compared to placebo or bisphosphonates, respectively.” The Company attributed the study failure to a “low fracture rate in the placebo group” of Orbit and a trend that fell shy of statistical significance in Cosmic. On this news, the price of Ultragenyx's stock fell from a closing market price of $34.19 per share on December 26, 2025, to $19.72 per share on December 29, 2025, a decline of about 42.32% in the span of just a single day.
If you purchased or otherwise acquired Ultragenyx shares and suffered a loss, are a long-term stockholder, have information, would like to learn more about these claims, or have any questions concerning this announcement or your rights or interests with respect to these matters, please contact Brandon Walker or Melissa Fortunato by email at investigations@bespc.com, telephone at (212) 355-4648, or by filling out this contact form. There is no cost or obligation to you.
About Bragar Eagel & Squire, P.C.:
Bragar Eagel & Squire, P.C. is a nationally recognized law firm with offices in New York, South Carolina, and California. The firm represents individual and institutional investors in securities, derivative, and commercial litigation as well as individuals in consumer protection and data privacy litigation. The firm has a nationwide practice and routinely handles cases in both federal and state courts. For more information about the firm, please visit www.bespc.com.  Attorney advertising.  Prior results do not guarantee similar outcomes.
Follow us for updates on LinkedIn and Facebook, and keep up with other news by following Brandon Walker, Esq. on LinkedIn.
Contact Information:
Bragar Eagel & Squire, P.C.
Brandon Walker, Esq.
Melissa Fortunato, Esq.

Frequently Asked Questions

What is the lawsuit about regarding Ultragenyx?

The lawsuit addresses claims that Ultragenyx misled investors about the results of its Phase III studies on setrusumab.

Who should contact Bragar Eagel & Squire?

Investors who bought Ultragenyx stock between August 3, 2023, and December 26, 2025, should reach out.

When is the deadline to join the lawsuit?

The deadline to apply as lead plaintiff is April 6, 2026.

What triggered the drop in Ultragenyx's stock price?

The stock price fell after the company announced its studies did not meet primary endpoints.

How can investors get more information about the lawsuit?

Investors can contact Brandon Walker or Melissa Fortunato via email or phone for details.

Last updated: Feb 5, 2026