NEW YORK , Feb. 16, 2026 /PRNewswire/ --

Why: Rosen Law Firm, a global investor rights law firm, reminds purchasers of common stock of Ultragenyx Pharmaceutical Inc. (NASDAQ: RARE) between August 3, 2023 and December 26, 2025, inclusive (the "Class Period"), of the important April 6, 2026 lead plaintiff deadline.

So what: If you purchased Ultragenyx common stock during the Class Period you may be entitled to compensation without payment of any out of pocket fees or costs through a contingency fee arrangement.

What to do next: 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. A class action lawsuit has already been filed. If you wish to serve as lead plaintiff, you must move the Court no later than April 6, 2026. A lead plaintiff is a representative party acting on behalf of other class members in directing the litigation.

Why Rosen Law: We encourage investors to select qualified counsel with a track record of success in leadership roles. Often, firms issuing notices do not have comparable experience, resources, or any meaningful peer recognition. Many of these firms do not actually litigate securities class actions, but are merely middlemen that refer clients or partner with law firms that actually litigate the cases. Be wise in selecting counsel. The Rosen Law Firm represents investors throughout the globe, concentrating its practice in securities class actions and shareholder derivative litigation. Rosen Law Firm has achieved, at that time, the largest ever securities class action settlement against a Chinese Company. Rosen Law Firm was Ranked No. 1 by ISS Securities Class Action Services for number of securities class action settlements in 2017. The firm has been ranked in the top 4 each year since 2013 and has recovered hundreds of millions of dollars for investors. In 2019 alone the firm secured over $438 million for investors. In 2020, founding partner Laurence Rosen was named by law360 as a Titan of Plaintiffs' Bar. Many of the firm's attorneys have been recognized by Lawdragon and Super Lawyers.

Details of the case: According to the lawsuit, 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.

The lawsuit claims that defendants provided these overwhelmingly positive statements to investors while simultaneously disseminating materially false and misleading statements and/or concealing material adverse facts concerning the true state of setrusumab's potential, as well as 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, that the Phase III Orbit and Cosmic studies were much less likely to be able to demonstrate such a link than management claimed. The lawsuit claims that such statements absent these material facts caused Ultragenyx shareholders to purchase Ultragenyx securities at artificially inflated prices. When the true details entered the market, the lawsuit claims that investors suffered damages.

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.

No Class Has Been Certified. Until a class is certified, you are not represented by counsel unless you retain one. You may select counsel of your choice. You may also remain an absent class member and do nothing at this point. An investor's ability to share in any potential future recovery is not dependent upon serving as lead plaintiff.

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Contact Information:

      Laurence Rosen, Esq.
      Phillip Kim, Esq.
      The Rosen Law Firm, P.A.
      275 Madison Avenue, 40th Floor
      New York, NY 10016
      Tel: (212) 686-1060
      Toll Free: (866) 767-3653
      Fax: (212) 202-3827
      case@rosenlegal.com
      www.rosenlegal.com

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