Kessler Topaz Meltzer & Check, LLP announced a securities fraud class action filed on behalf of investors who purchased Ultragenyx Pharmaceutical Inc. common stock between August 3, 2023 and December 26, 2025.

Kessler Topaz Meltzer & Check, LLP (www.ktmc.com) informs investors that a securities fraud class action lawsuit has been filed against Ultragenyx Pharmaceutical Inc. (Ultragenyx) (NASDAQ: RARE) on behalf of those who purchased or acquired Ultragenyx common stock between August 3, 2023, and December 26, 2025, inclusive. The lawsuit is filed in the United States District Court for the Northern District of California and is captioned Bailey v. Ultragenyx Pharmaceutical Inc., et al, Case No. 3:26-cv-01097 (N.D. Cal.).   Investors have until April 6, 2026, to file for lead plaintiff status.  

ULTRAGENYX PHARMACEUTICAL INC. CLASS ACTION LAWSUIT - COMPLAINT ALLEGATION SUMMARY:

The complaint alleges that, throughout the Class Period, Defendants made false and/or misleading statements and/or failed to disclose that: (1) Ultragenyx created the false impression that they possessed reliable information pertaining to the effects of the company's drug, setrusumab, on patients with variable types of Osteogenesis Imperfecta, while also minimizing risk that patients in Ultragenyx's Phase III Orbit study would fail to achieve a statistically significant reduction in annualized fracture rate ("AFR"), such that the second interim analysis could be performed and presented to the investing public; (2) in truth, Ultragenyx's optimism in the Phase III Orbit study's results and interim analysis benchmark were misplaced because Ultragenyx failed to convey the risk associated with basing such threshold figures on Phase II results that had no placebo control group for appropriate comparison and thus had not ruled out that the reduction in AFR from that study could merely be triggered by an increased standard of care and the placebo effect of being provided a novel treatment; and (3) as a result, Defendants' positive statements about the company's business, operations, and prospects were materially misleading and/or lacked a reasonable basis.

WHAT RARE INVESTORS CAN DO NOW:

File to be lead plaintiff by April 6, 2026.

Contact KTMC for a free case evaluation.

Retain counsel of choice or take no action.

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