Ultragenyx's Gene Therapy Application Accepted by FDA
Written by Emily J. Thompson, Senior Investment Analyst
Updated: 1 hour ago
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Should l Buy RARE?
Source: seekingalpha
- 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.
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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.
- 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.
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- 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.
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- 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.
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- 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.
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- 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.
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- Lawsuit Background: Kahn Swick & Foti LLC has initiated a class action lawsuit against Ultragenyx Pharmaceutical, alleging securities fraud affecting investors from August 3, 2023, to December 26, 2025, aiming to recover losses for impacted shareholders.
- Study Failure Impact: On December 26, 2025, Ultragenyx disclosed that its Phase 3 studies for setrusumab in Osteogenesis Imperfecta failed to show a statistically significant reduction in fracture rates, resulting in a dramatic 42% drop in share price within three days.
- Stock Price Volatility: Following the announcement, Ultragenyx's stock plummeted from $34.19 to $19.72 per share, indicating severe market concerns regarding the company's operational and financial outlook, prompting management to consider significant expense reductions.
- Investor Action: Affected investors have until April 6, 2026, to request lead plaintiff status, although eligibility for any recovery does not require serving as lead plaintiff, highlighting the legal avenues available for investor protection.
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