Rosen Law Firm Encourages Ultragenyx Investors to Secure Counsel Before Deadline

Class action lawsuit filed on behalf of Ultragenyx Pharmaceutical Inc. investors

Published on Feb. 13, 2026

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The Rosen Law Firm, a global investor rights law firm, has announced a class action lawsuit on behalf of purchasers of common stock of Ultragenyx Pharmaceutical Inc. (NASDAQ: RARE) between August 3, 2023 and December 26, 2025. The firm is encouraging investors to secure counsel before the April 6, 2026 deadline to potentially join the class action.

Why it matters

The lawsuit alleges that Ultragenyx made false and/or misleading statements and/or concealed material adverse facts concerning the true state of setrusumab's potential and the true risk inherent in the study protocols. If the allegations are true, investors who purchased Ultragenyx stock during the class period may be entitled to compensation.

The details

According to the lawsuit, the defendants claimed 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. The lawsuit alleges that when the true details entered the market, investors suffered damages.

  • The class period is from August 3, 2023 to December 26, 2025.
  • The deadline for investors to move the Court to serve as lead plaintiff is April 6, 2026.

The players

Rosen Law Firm

A global investor rights law firm that has announced the class action lawsuit on behalf of Ultragenyx investors.

Ultragenyx Pharmaceutical Inc.

A biopharmaceutical company that develops and commercializes novel products for the treatment of rare and ultra-rare genetic diseases in the United States.

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What they’re saying

“To join the Ultragenyx class action, go to https://rosenlegal.com/submit-form/?case_id=52472 or call Phillip Kim, Esq. toll-free at 866-767-3653 or email case@rosenlegal.com for information on the class action.”

— Phillip Kim, Esq. (Rosen Law Firm)

What’s next

The judge will decide on April 6, 2026 whether to allow the class action lawsuit to proceed.

The takeaway

This class action lawsuit highlights the importance for investors to be vigilant and seek qualified legal counsel if they believe a company has made false or misleading statements that have resulted in financial losses. The Rosen Law Firm is encouraging Ultragenyx investors to secure counsel before the upcoming deadline to potentially join the class action.