Ultragenyx Pharmaceutical Inc. Notice of April 6, 2026 Application Deadline for Class Action Lawsuit - Contact Lewis Kahn, Esq. at Kahn Swick & Foti, LLC, Before Application Deadline

Rhea-AI Impact

(Moderate)

Rhea-AI Sentiment

(Very Negative)

Rhea-AI Summary

News Market Reaction – RARE

-1.58%

-1.58% Session close to close

In the Mar 2 session, RARE declined 1.58%, reflecting a mild negative market reaction.

Data tracked by StockTitan Argus on the day of publication.

Market Context

This announcement reiterates a securities class action focused on losses following UX143’s failed Ph...

Analysis

This announcement reiterates a securities class action focused on losses following UX143’s failed Phase 3 studies, which previously drove a 42% share-price decline from $34.19 to $19.72. It highlights an April 6, 2026 deadline to seek lead-plaintiff status but does not introduce new business fundamentals. In context of recent FDA Priority Reviews and restructuring actions, this legal overhang underscores the importance of tracking trial outcomes, regulatory milestones, and any additional litigation developments alongside core operating performance.

Key Figures

Share price drop: 42% Price before drop: $34.19 per share Price after drop: $19.72 per share +4 more

7 metrics

Share price drop 42% Decline after Dec 26, 2025 UX143 Phase 3 results

Price before drop $34.19 per share Ultragenyx closing price on Dec 26, 2025

Price after drop $19.72 per share Ultragenyx closing price on Dec 29, 2025

Class period start August 3, 2023 Beginning of alleged securities fraud class period

Class period end December 26, 2025 End of alleged securities fraud class period

Lead plaintiff deadline April 6, 2026 Deadline to seek appointment as lead plaintiff

Case number 26-cv-01097 Captioned case: Steven Bailey v. Ultragenyx Pharmaceutical Inc., et al.

Historical Context

5 past events · Latest: Feb 24 (Negative)

Pattern 5 events

Date	Event	Sentiment	24h Move	Catalyst
Feb 24	Class action update	Negative	+0.7%	Reminder of class action lawsuit and April 6, 2026 lead-plaintiff deadline.
Feb 23	Investor conferences	Positive	+1.1%	Announcement of participation in three March 2026 healthcare investor conferences.
Feb 23	BLA priority review	Positive	-0.9%	FDA acceptance and Priority Review of BLA for DTX401 with August 23, 2026 PDUFA date.
Feb 20	Inducement grant	Neutral	-0.9%	Grant of 22,917 RSUs to six new non-executive officers under inducement plan.
Feb 13	Class action notice	Negative	-1.7%	Initial notice of April 6, 2026 lead-plaintiff deadline in class action lawsuit.

24h Move is the share-price change in the day after each event; other market factors may also have contributed.

Pattern Detected

Newsflow has recently mixed positive regulatory progress with legal overhang; price reactions have alternated between alignment and divergence, indicating inconsistent trading responses to catalysts.

Recent Company History

Over recent months, Ultragenyx has balanced regulatory progress with legal and restructuring headlines. An 8-K on FDA Priority Review for DTX401 and multiple UX111 updates highlighted late-stage gene therapy momentum. At the same time, the company reported heavy 2025 losses, a 10% workforce reduction, and repeated class action lawsuit notices, including a prior lead-plaintiff deadline alert on Feb 13, 2026. Price reactions to these items have been mixed, with both aligned and divergent moves versus the apparent sentiment of each event.

Key Terms

class action securities lawsuit, securities fraud, Phase 3, Phase III, +3 more

7 terms

class action securities lawsuit regulatory

"notifies investors in Ultragenyx Pharmaceutical Inc. ("Ultragenyx" ) (NasdaqGS: RARE) of a class action securities lawsuit."

A class action securities lawsuit is a legal claim brought collectively by a group of investors who say they were harmed by a company’s false or misleading statements, bad accounting, or failure to disclose important facts. It matters to investors because outcomes — settlements, fines, leadership changes or prolonged legal costs — can reduce a company’s cash, damage its reputation and depress the stock price, similar to many neighbors joining one lawsuit that drains a builder’s resources.

securities fraud regulatory

"recover losses on behalf of investors of Ultragenyx who were adversely affected by alleged securities fraud between August 3, 2023 and December 26, 2025."

Securities fraud is the illegal act of lying to or misleading investors about the true value or prospects of stocks, bonds or other traded financial instruments — for example by making false statements, hiding key facts, trading on secret information, or artificially moving prices. It matters to investors because it can cause sudden losses, distort fair market prices and undermine trust in markets; think of it as someone rigging a scoreboard so others place bets on the wrong team.

View in glossary

Phase 3 medical

"the Company announced the "results from the Phase 3 Orbit and Cosmic studies for setrusumab (UX143)"

Phase 3 is the late-stage clinical testing step for a new drug or medical treatment, where the product is given to large groups of patients to confirm effectiveness, monitor side effects, and compare it to standard care. Successful Phase 3 results are often the final scientific hurdle before regulators decide on approval and market launch—like passing a final exam before graduation—and can sharply change a company's valuation and future revenue prospects.

Phase III medical

"disclosing that both its Phase III Orbit and Cosmic studies failed to demonstrate that setrusumab"

A Phase III trial is the late-stage clinical study that tests whether a medical treatment works and is safe in a large group of patients, often comparing it to standard care. Think of it as a final dress rehearsal or full-scale road test before regulators decide on approval; positive or negative results strongly influence a drug maker’s chance to sell the treatment, future revenue, and investment risk.

statistically significant medical

"failed to demonstrate that setrusumab triggered a statistically significant reduction in annualized fracture rates"

"Statistically significant" means that a result or difference observed in data is unlikely to have occurred by chance alone, suggesting there is a real underlying effect. For investors, it indicates that the findings or patterns they see are likely meaningful and not just random noise, helping them make more informed decisions based on reliable information. Think of it as a pattern that is strong enough to stand out clearly from background randomness.

Osteogenesis Imperfecta medical

"setrusumab (UX143) in Osteogenesis Imperfecta" disclosing that both its Phase III Orbit and Cosmic studies failed"

A genetic disorder that makes bones unusually fragile because the body produces faulty or too little of the protein that gives bone its strength; think of bones like a building made from weak bricks rather than strong ones. Investors track it because treatments, diagnostics, or therapies for the condition can create markets, affect clinical trial outcomes, regulatory approvals, and potential revenue for biotech and pharmaceutical companies developing interventions.

lead plaintiff regulatory

"you have until April 6, 2026 to request that the Court appoint you as lead plaintiff"

The lead plaintiff is the representative investor chosen to speak and act on behalf of a group of shareholders in a securities lawsuit. Think of them as the elected spokesperson for a neighborhood when everyone sues a landlord: they coordinate the legal case, make strategic decisions, and negotiate settlements, so their choices can shape outcomes and any recovery that reaches all affected investors. Investors care because the lead plaintiff’s resources and approach can influence the size and speed of any payout and the costs deducted from it.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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02/27/2026 - 10:08 PM

NEW YORK and NEW ORLEANS, Feb. 27, 2026 /PRNewswire/ -- Kahn Swick & Foti, LLC ("KSF") and KSF partner, former Attorney General of Louisiana, Charles C. Foti, Jr., notifies investors in Ultragenyx Pharmaceutical Inc. ("Ultragenyx" or the "Company") (NasdaqGS: RARE) of a class action securities lawsuit.

CLASS DEFINITION: The lawsuit seeks to recover losses on behalf of investors of Ultragenyx who were adversely affected by alleged securities fraud between August 3, 2023 and December 26, 2025. Follow the link below to get more information and be contacted by a member of our team:

https://www.ksfcounsel.com/cases/nasdaqgs-rare/

Ultragenyx investors should contact KSF Managing Partner Lewis Kahn toll-free at 1-877-515-1850 or via email (lewis.kahn@ksfcounsel.com), or visit https://www.ksfcounsel.com/cases/nasdaqgs-rare/ to learn more.

CASE DETAILS: On December 26, 2025, the Company announced the "results from the Phase 3 Orbit and Cosmic studies for setrusumab (UX143) in Osteogenesis Imperfecta" disclosing that both its Phase III Orbit and Cosmic studies failed to demonstrate that setrusumab triggered a statistically significant reduction in annualized fracture rates for patients with osteogenesis imperfecta, and, as a result the Company "is evaluating its planned operations and will promptly define and implement significant expense reductions." On this news, the price of Ultragenyx's shares fell approximately 42%, from $34.19 per share on December 26, 2025 to $19.72 per share on December 29, 2025.

The case is Steven Bailey v. Ultragenyx Pharmaceutical Inc., et al., No. 26-cv-01097.

WHAT TO DO? If you invested in Ultragenyx and suffered a loss during the relevant time frame, you have until April 6, 2026 to request that the Court appoint you as lead plaintiff; however, your ability to share in any recovery does not require that you serve as a lead plaintiff.

About Kahn Swick & Foti, LLC

KSF, whose partners include former Louisiana Attorney General Charles C. Foti, Jr., is one of the nation's premier boutique securities litigation law firms. This past year, KSF was ranked by SCAS among the top 10 firms nationally based upon total settlement value. KSF serves a variety of clients, including public and private institutional investors, and retail investors - in seeking recoveries for investment losses emanating from corporate fraud or malfeasance by publicly traded companies. KSF has offices in New York, Delaware, California, Louisiana, Chicago, and a representative office in Luxembourg.

TOP 10 Plaintiff Law Firms - According to ISS Securities Class Action Services

To learn more about KSF, you may visit www.ksfcounsel.com.

Contact:
Kahn Swick & Foti, LLC
Lewis Kahn, Managing Partner
lewis.kahn@ksfcounsel.com
1-877-515-1850
1100 Poydras St., Suite 960
New Orleans, LA 70163

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