Rosen Law Firm Encourages Ultragenyx Investors to Secure Counsel Before Deadline

Investors who purchased Ultragenyx stock between August 2023 and December 2025 may be eligible for compensation.

Mar. 16, 2026 at 4:03am

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Rosen Law Firm, a global investor rights law firm, is reminding purchasers of Ultragenyx Pharmaceutical Inc. (NASDAQ: RARE) common stock between August 3, 2023 and December 26, 2025 of the important April 6, 2026 lead plaintiff deadline in a securities class action lawsuit. The lawsuit claims that Ultragenyx provided investors with materially false and misleading information about its drug setrusumab and the potential results of its Phase III clinical trials.

Why it matters

This case highlights the importance of transparency and accurate disclosures from pharmaceutical companies to investors. Ultragenyx is accused of overstating the potential of its drug candidate setrusumab, which could have led investors to purchase the stock at artificially inflated prices. The class action lawsuit aims to recover damages for investors who were allegedly harmed by Ultragenyx's actions.

The details

The lawsuit claims that Ultragenyx provided investors with overwhelmingly positive statements about setrusumab's ability to reduce fracture rates in patients with Osteogenesis Imperfecta, while concealing material adverse facts. Specifically, the lawsuit alleges that while setrusumab does increase bone density, this increase does not correlate to a decrease in fracture rates, and the Phase III studies were much less likely to demonstrate such a link than Ultragenyx claimed.

  • The class period is from August 3, 2023 to December 26, 2025.
  • The lead plaintiff deadline is April 6, 2026.

The players

Ultragenyx Pharmaceutical Inc.

A biopharmaceutical company focused on developing and commercializing novel products for rare and ultra-rare genetic diseases.

Rosen Law Firm

A global investor rights law firm that concentrates its practice in securities class actions and shareholder derivative litigation.

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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 case to proceed as a class action lawsuit.

The takeaway

This case highlights the importance of pharmaceutical companies providing accurate and transparent information to investors about the potential of their drug candidates. Investors who purchased Ultragenyx stock during the class period may be eligible for compensation if the lawsuit is successful.