Class Action Filed Against Ultragenyx Pharmaceutical Inc.
Written by Emily J. Thompson, Senior Investment Analyst
Updated: Feb 06 2026
0mins
Should l Buy RARE?
Source: PRnewswire
- Lawsuit Background: National plaintiffs' law firm Berger Montague PC has announced a class action lawsuit against Ultragenyx Pharmaceutical Inc. on behalf of investors who purchased stock between August 3, 2023, and December 26, 2025, indicating a significant loss of investor confidence in the company's future prospects.
- Stock Price Plunge: Following the disclosure on December 29, 2025, that Ultragenyx's ORBIT and COSMIC Phase 3 trials failed to meet their primary endpoints, the stock price plummeted over 42%, from $34.19 per share on December 26, 2025, to $19.72 per share, reflecting a pessimistic outlook from the market regarding the company's future.
- Investor Rights: Investors must apply by April 6, 2026, to be appointed as lead plaintiff representatives in the class action, highlighting concerns over corporate governance and information disclosure that may influence future investment decisions.
- Law Firm's Strength: Berger Montague, a leading law firm specializing in complex civil litigation and class actions, has recovered over $50 billion for clients over the past 55 years, showcasing its significant strength and influence in the legal field.
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Analyst Views on RARE
Wall Street analysts forecast RARE stock price to rise
18 Analyst Rating
17 Buy
1 Hold
0 Sell
Strong Buy
Current: 21.420
Low
35.00
Averages
61.65
High
120.00
Current: 21.420
Low
35.00
Averages
61.65
High
120.00
About RARE
Ultragenyx Pharmaceutical Inc. is a biopharmaceutical company. The Company is focused on the identification, acquisition, development, and commercialization of novel products for the treatment of serious rare and ultrarare genetic diseases. Its therapies and clinical-stage pipeline consist of four product categories: biologics, small molecules, AAV gene therapy, and nucleic acid product candidates. Its four approved product candidates include Crysvita (burosumab) for the treatment of X-linked hypophosphatemia (XLH), and tumor-induced osteomalacia (TIO), Mepsevii (vestronidase alfa) for the treatment of mucopolysaccharidosis VII (MPSVII) or Sly Syndrome, Dojolvi (triheptanoin) for the treatment of long-chain fatty acid oxidation disorders (LC-FAOD), and Evkeeza (evinacumab) for the treatment of homozygous familial hypercholesterolemia (HoFH). Its clinical product candidates include DTX401, DTX301, UX701, UX143, UX111, and GTX-102. UX143 for the treatment of Osteogenesis Imperfecta.
About the author
Emily J. Thompson
Emily J. Thompson, a Chartered Financial Analyst (CFA) with 12 years in investment research, graduated with honors from the Wharton School. Specializing in industrial and technology stocks, she provides in-depth analysis for Intellectia’s earnings and market brief reports.
UX111 Poised to Be First Therapy for Sanfilippo Syndrome Type A
- FDA Review Progress: Ultragenyx's Biologics License Application (BLA) for UX111 has been accepted for review by the FDA, with a decision expected by September 19, 2026, marking a significant step towards providing the first effective treatment for Sanfilippo syndrome Type A, which could greatly benefit affected families.
- Clinical Data Support: Updated long-term clinical data indicate that UX111 demonstrates durable treatment effects across multiple biomarker evaluations while maintaining an acceptable safety profile, providing robust support for the FDA's accelerated approval process, which could significantly enhance patient quality of life.
- Manufacturing Capability Assurance: If approved, UX111 will be manufactured at Andelyn Biosciences and Ultragenyx's facilities in the U.S., ensuring product quality and supply chain stability, while also accelerating market entry to meet urgent patient needs.
- Significant Market Potential: Sanfilippo syndrome Type A affects approximately 3,000 to 5,000 patients with no current effective treatments; the successful launch of UX111 would fill this market gap, potentially yielding substantial economic returns and market share for Ultragenyx.
See More
Ultragenyx's Gene Therapy Application Accepted by FDA
- FDA Application Acceptance: Ultragenyx Pharmaceutical announced that its biologics license application for gene therapy candidate UX111 has been accepted by the FDA, with a target action date set for September 19, 2026, aiming for accelerated approval to treat the fatal rare lysosomal storage disease Sanfilippo syndrome Type A.
- Regulatory Feedback Response: In July 2025, the FDA issued a complete response letter declining to approve the AAV gene therapy due to manufacturing-related issues, highlighting the regulatory body's stringent requirements for product quality and safety.
- U.S. Production Plans: Pending FDA approval, Ultragenyx plans to manufacture UX111 entirely at U.S.-based sites, including its gene therapy manufacturing facility in Bedford, Massachusetts, which will help ensure compliance and quality control in production processes.
- Market Outlook: With the FDA's acceptance of the application, Ultragenyx's market potential in the rare disease sector is significantly enhanced, and a successful launch of UX111 could provide substantial commercial opportunities and competitive advantages for the company.
See More
Ultragenyx Pharmaceutical Faces Class Action Lawsuit
- Class Action Initiated: National plaintiffs' law firm Berger Montague PC has announced a class action lawsuit against Ultragenyx Pharmaceutical, representing investors who purchased shares between August 3, 2023, and December 26, 2025, highlighting significant investor concerns regarding company transparency.
- Severe Investor Losses: The lawsuit alleges that Ultragenyx misrepresented results from the ORBIT and COSMIC Phase 3 trials, leading to a more than 42% drop in share price on December 29, 2025, when the truth was revealed, reflecting a sharp decline in market confidence in the company's performance.
- Investor Representative Deadline: Investors must apply to be appointed as lead plaintiff representatives by April 6, 2026, indicating the urgency of the legal process and the protection of investor rights.
- Law Firm Background: Berger Montague is one of the nation's leading firms in complex civil litigation and class actions, having recovered over $50 billion for clients over the past 55 years, demonstrating its strong capabilities and influence in the legal field.
See More
Ultragenyx Securities Class Action Reminder
- Deadline Reminder: ClaimsFiler informs investors that those who purchased Ultragenyx shares between August 3, 2023, and December 26, 2025, must file lead plaintiff applications by April 6, 2026, to participate in the securities class action lawsuit.
- Legal Allegations: Ultragenyx and certain executives are accused of failing to disclose material information during the class period, violating federal securities laws, which has resulted in significant losses for investors.
- Stock Price Plunge: Following the December 26, 2025 announcement that setrusumab (UX143) failed to show a statistically significant reduction in fracture rates, Ultragenyx's stock price plummeted approximately 42%, from $34.19 to $19.72, indicating a pessimistic market outlook on the company's future.
- Legal Assistance Offered: ClaimsFiler provides free legal consultation services, allowing investors to access relevant information and submit claims promptly to recover losses from the securities class action lawsuit.
See More
Ultragenyx Seeks Accelerated Approval for UX111 Gene Therapy
- FDA Acceptance: Ultragenyx Pharmaceutical announced that the FDA has accepted its resubmitted Biologics License Application for UX111, aimed at accelerating approval for treating Sanfilippo syndrome Type A, indicating significant progress in the rare disease sector.
- Key Timeline: The FDA has set a Prescription Drug User Fee Act action date of September 19, 2026, which will have a crucial impact on the company's future market strategy and cash flow.
- Clinical Data Support: During the prior late-cycle review, the FDA acknowledged the robustness of neurodevelopmental outcomes and noted that biomarker data provided additional supportive evidence, indicating the potential efficacy and safety of UX111 in treatment.
- Long-term Efficacy Validation: Updated long-term clinical data show that, compared to natural disease progression, UX111 demonstrates sustained clinical benefits and durable treatment effects over up to eight years of follow-up, enhancing the company's competitive position in the gene therapy field.
See More
Ultragenyx Pharmaceutical Faces Class Action Lawsuit
- Lawsuit Background: National plaintiffs’ law firm Berger Montague PC has announced a class action lawsuit against Ultragenyx Pharmaceutical, representing investors who purchased stock from August 3, 2023, to December 26, 2025, alleging misleading information regarding clinical trials.
- Stock Price Plunge: Following the disclosure that the ORBIT and COSMIC studies did not significantly reduce clinical fracture rates for Osteogenesis Imperfecta, Ultragenyx's stock price plummeted from $34.19 on December 26, 2025, to $19.72, erasing over 42% of its value in a single day, severely impacting investor confidence.
- Investor Rights: Investors must apply by April 6, 2026, to be appointed as lead plaintiff representatives in the class action, highlighting the importance of legal processes in protecting investor rights.
- Law Firm's Strength: Berger Montague, a leading law firm specializing in complex civil litigation and class actions, has recovered over $50 billion for clients over the past 55 years, demonstrating its significant influence in the legal field.
See More
UX111 Poised to Be First Therapy for Sanfilippo Syndrome Type A
- FDA Review Progress: Ultragenyx's Biologics License Application (BLA) for UX111 has been accepted for review by the FDA, with a decision expected by September 19, 2026, marking a significant step towards providing the first effective treatment for Sanfilippo syndrome Type A, which could greatly benefit affected families.
- Clinical Data Support: Updated long-term clinical data indicate that UX111 demonstrates durable treatment effects across multiple biomarker evaluations while maintaining an acceptable safety profile, providing robust support for the FDA's accelerated approval process, which could significantly enhance patient quality of life.
- Manufacturing Capability Assurance: If approved, UX111 will be manufactured at Andelyn Biosciences and Ultragenyx's facilities in the U.S., ensuring product quality and supply chain stability, while also accelerating market entry to meet urgent patient needs.
- Significant Market Potential: Sanfilippo syndrome Type A affects approximately 3,000 to 5,000 patients with no current effective treatments; the successful launch of UX111 would fill this market gap, potentially yielding substantial economic returns and market share for Ultragenyx.
See More
Ultragenyx's Gene Therapy Application Accepted by FDA
- FDA Application Acceptance: Ultragenyx Pharmaceutical announced that its biologics license application for gene therapy candidate UX111 has been accepted by the FDA, with a target action date set for September 19, 2026, aiming for accelerated approval to treat the fatal rare lysosomal storage disease Sanfilippo syndrome Type A.
- Regulatory Feedback Response: In July 2025, the FDA issued a complete response letter declining to approve the AAV gene therapy due to manufacturing-related issues, highlighting the regulatory body's stringent requirements for product quality and safety.
- U.S. Production Plans: Pending FDA approval, Ultragenyx plans to manufacture UX111 entirely at U.S.-based sites, including its gene therapy manufacturing facility in Bedford, Massachusetts, which will help ensure compliance and quality control in production processes.
- Market Outlook: With the FDA's acceptance of the application, Ultragenyx's market potential in the rare disease sector is significantly enhanced, and a successful launch of UX111 could provide substantial commercial opportunities and competitive advantages for the company.
See More
Ultragenyx Pharmaceutical Faces Class Action Lawsuit
- Class Action Initiated: National plaintiffs' law firm Berger Montague PC has announced a class action lawsuit against Ultragenyx Pharmaceutical, representing investors who purchased shares between August 3, 2023, and December 26, 2025, highlighting significant investor concerns regarding company transparency.
- Severe Investor Losses: The lawsuit alleges that Ultragenyx misrepresented results from the ORBIT and COSMIC Phase 3 trials, leading to a more than 42% drop in share price on December 29, 2025, when the truth was revealed, reflecting a sharp decline in market confidence in the company's performance.
- Investor Representative Deadline: Investors must apply to be appointed as lead plaintiff representatives by April 6, 2026, indicating the urgency of the legal process and the protection of investor rights.
- Law Firm Background: Berger Montague is one of the nation's leading firms in complex civil litigation and class actions, having recovered over $50 billion for clients over the past 55 years, demonstrating its strong capabilities and influence in the legal field.
See More
Ultragenyx Securities Class Action Reminder
- Deadline Reminder: ClaimsFiler informs investors that those who purchased Ultragenyx shares between August 3, 2023, and December 26, 2025, must file lead plaintiff applications by April 6, 2026, to participate in the securities class action lawsuit.
- Legal Allegations: Ultragenyx and certain executives are accused of failing to disclose material information during the class period, violating federal securities laws, which has resulted in significant losses for investors.
- Stock Price Plunge: Following the December 26, 2025 announcement that setrusumab (UX143) failed to show a statistically significant reduction in fracture rates, Ultragenyx's stock price plummeted approximately 42%, from $34.19 to $19.72, indicating a pessimistic market outlook on the company's future.
- Legal Assistance Offered: ClaimsFiler provides free legal consultation services, allowing investors to access relevant information and submit claims promptly to recover losses from the securities class action lawsuit.
See More
Ultragenyx Seeks Accelerated Approval for UX111 Gene Therapy
- FDA Acceptance: Ultragenyx Pharmaceutical announced that the FDA has accepted its resubmitted Biologics License Application for UX111, aimed at accelerating approval for treating Sanfilippo syndrome Type A, indicating significant progress in the rare disease sector.
- Key Timeline: The FDA has set a Prescription Drug User Fee Act action date of September 19, 2026, which will have a crucial impact on the company's future market strategy and cash flow.
- Clinical Data Support: During the prior late-cycle review, the FDA acknowledged the robustness of neurodevelopmental outcomes and noted that biomarker data provided additional supportive evidence, indicating the potential efficacy and safety of UX111 in treatment.
- Long-term Efficacy Validation: Updated long-term clinical data show that, compared to natural disease progression, UX111 demonstrates sustained clinical benefits and durable treatment effects over up to eight years of follow-up, enhancing the company's competitive position in the gene therapy field.
See More
Ultragenyx Pharmaceutical Faces Class Action Lawsuit
- Lawsuit Background: National plaintiffs’ law firm Berger Montague PC has announced a class action lawsuit against Ultragenyx Pharmaceutical, representing investors who purchased stock from August 3, 2023, to December 26, 2025, alleging misleading information regarding clinical trials.
- Stock Price Plunge: Following the disclosure that the ORBIT and COSMIC studies did not significantly reduce clinical fracture rates for Osteogenesis Imperfecta, Ultragenyx's stock price plummeted from $34.19 on December 26, 2025, to $19.72, erasing over 42% of its value in a single day, severely impacting investor confidence.
- Investor Rights: Investors must apply by April 6, 2026, to be appointed as lead plaintiff representatives in the class action, highlighting the importance of legal processes in protecting investor rights.
- Law Firm's Strength: Berger Montague, a leading law firm specializing in complex civil litigation and class actions, has recovered over $50 billion for clients over the past 55 years, demonstrating its significant influence in the legal field.
See More
