NASDAQ: RARE: Law firm announces filing of securities lawsuit

In the period between August 3, 2023, and December 26, 2025, were you a purchaser of RARE common stock? A class action lawsuit regarding securities fraud has been initiated against Ultragenyx Pharmaceutical Inc., with key allegations related to the company’s drug, setrusumab.

Throughout the Class Period, Ultragenyx Pharmaceutical Inc. (NASDAQ: RARE) allegedly made misleading statements and omissions concerning their drug, setrusumab, particularly in their Phase III Orbit study. It is claimed that Ultragenyx gave the impression that they possessed reliable information on the effects of setrusumab while downplaying the risks associated with the study’s results.

Defendants had allegedly minimized the risk that patients in the Phase III Orbit study would not achieve a statistically significant reduction in annualized fracture rate (AFR) necessary for the second interim analysis, which would then be presented to the public. The lawsuit alleges that Ultragenyx’s optimism was misplaced, as the company failed to communicate the potential risks involved in basing their benchmark figures on Phase II results that lacked a placebo control group for a proper comparison.

It is further claimed that Ultragenyx’s positive statements about the company’s business, operations, and prospects were misleading and lacked a reasonable basis. Investors who were affected by these alleged actions have until April 6, 2026, to seek lead plaintiff status in the lawsuit.

If you purchased or acquired Ultragenyx Pharmaceutical Inc. common stock during the specified period and suffered losses, it is suggested that you contact Kessler Topaz Meltzer & Check, LLP to discuss your legal rights. You can reach out to the firm for a free case evaluation and explore your options moving forward.

Investors in Ultragenyx have the opportunity to seek appointment as a lead plaintiff representative of the class by April 6, 2026. A lead plaintiff typically represents all class members in litigation and selects counsel to guide the legal proceedings. Whether or not to serve as a lead plaintiff does not affect an investor’s ability to share in any potential recovery from the lawsuit.

Kessler Topaz Meltzer & Check, LLP is experienced in handling securities-fraud class actions and is available to provide Ultragenyx investors with more information about the ongoing legal proceedings. The firm has a strong track record of securing notable recoveries in securities litigation and is dedicated to protecting the interests of individual and institutional investors alike.