What are the main allegations in the Ultragenyx Pharmaceutical securities class action lawsuit?

The lawsuit alleges that Ultragenyx misled investors regarding the Phase III Orbit and Cosmic studies for setrusumab. Specifically, it claims the company concealed risks that improvements in bone mineral density would not translate to a statistically significant reduction in fracture rates.

What are the main allegations in the Ultragenyx Pharmaceutical securities class action lawsuit? The lawsuit alleges that Ultragenyx misled investors regarding the Phase III Orbit and Cosmic studies for setrusumab. Specifically, it claims the company concealed risks that improvements in bone mineral density would not translate to a statistically significant reduction in fracture rates. What caused the Ultragenyx stock price to drop significantly in July and December 2025?

The stock fell 25% in July 2025 after interim data for the Orbit study failed to reach statistical significance. It plunged another 42% on December 29, 2025, when Ultragenyx announced that both the Orbit and Cosmic studies failed their primary endpoints for reducing clinical fracture rates.

Who is eligible to join the Ultragenyx investor class action and what is the class period?

Investors who purchased or acquired Ultragenyx ($RARE) common stock between August 3, 2023, and December 26, 2025, may be eligible. This "class period" defines the timeframe during which the company's public statements were allegedly false or misleading, leading to investor losses.

What is the deadline for Ultragenyx shareholders to seek the role of lead plaintiff?

The deadline to file a motion with the court to be appointed as lead plaintiff is April 6, 2026. A lead plaintiff is a representative party who acts on behalf of other class members in directing the litigation, though you do not need to be a lead plaintiff to share in any future recovery.

What were the specific primary and secondary endpoints in the Ultragenyx setrusumab clinical trials?

The primary endpoint was a statistically significant reduction in the annualized clinical fracture rate compared to a placebo or bisphosphonates. While the studies achieved secondary endpoints of improved bone mineral density, they failed to prove that this improvement actually reduced fractures.

Ultragenyx Pharmaceutical Inc. - Faruqi & Faruqi LLP

Ultragenyx Pharmaceutical Inc.

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Case Details

Filed On: February 4, 2026

Ticker RARE

Class Period 08/03/2023 - 12/26/2025

Lead Plaintiff Deadline 04/06/2026

Days Left to Seek Plaintiff

If you are a Ultragenyx Pharmaceutical investor who suffered a loss and would like to learn more, you can provide your information below:

If you purchased or acquired securities in Ultragenyx between August 3, 2023 and December 26, 2025 and would like to discuss your legal rights, call Faruqi & Faruqi partner Josh Wilson directly at 877-247-4292 or 212-983-9330 (Ext. 1310).

Faruqi & Faruqi, LLP, a leading national securities law firm, is investigating potential claims against Ultragenyx Pharmaceutical Inc (“Ultragenyx” or the “Company”) (NASDAQ: RARE) and reminds investors of the April 6, 2026 deadline to seek the role of lead plaintiff in a federal securities class action that has been filed against the Company.

STOCK DROP: On July 9, 2025, Ultragenyx revealed that the Phase III Orbit study failed to achieve statistical significance for the second interim analysis and that Phase III Orbit and Cosmic studies would now be “progressing toward final analysis.” On this news, the price of Ultragenyx stock fell more than 25%, according to the complaint. Then, on December 29, 2025, Ultragenyx announced that both its Phase III Orbit and Cosmic Studies had not “achieved statistical significance against the primary endpoints of reduction in annualized clinical fracture rate compared to placebo or bisphosphonates, respectively.” Ultragenyx allegedly attributed the study failure to a “low fracture rate in the placebo group” of Orbit and a trend that fell shy of statistical significance in Cosmic. On this news, the price of Ultragenyx stock fell more than 42%, according to the complaint.

Lead Plaintiff Deadline: April 6, 2026

Call Partner Josh Wilson at 877-247-4292 or 212-983-9330 (Ext. 1310)
Or submit your information below to learn about your rights.

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