Ultragenyx Pharmaceutical Inc.

Ultragenyx Announces Marketing Authorisation Application (MAA) Submission to the European Medicines Agency (EMA) for the First Investigational Gene Therapy for MPS IIIA (Sanfilippo Syndrome Type A)

BASEL, Switzerland, Oct. 02, 2026 (GLOBE NEWSWIRE) -- Today Ultragenyx announced that the European Medicines Agency (EMA) has validated the Company's Marketing Authorisation Application (MAA) for its investigational gene therapy, rebisufligene etisparvovec, for the treatment of mucopolysaccharidosis type IIIA (MPS IIIA), also known as Sanfilippo syndrome Type A.

EMA validation confirms that the application is sufficiently complete for the Agency to begin its formal scientific review. Validation does not constitute approval of the application, nor does it represent a determination regarding the safety or efficacy of the investigational therapy, nor guarantee that the application will ultimately receive marketing authorisation. "The validation of our application by the EMA marks an important regulatory milestone in the ongoing review process for this investigational therapy," said Jane Cooper, Senior Vice President and Region Head for Europe, Middle East and Africa at Ultragenyx. "We recognize the significant unmet need within the MPS IIIA community and continue to advance our global regulatory strategy with the European Medicines Agency (EMA). We also plan to expand to other geographies over time.”

MPS IIIA is a rare, progressive inherited disorder associated with severe neurological impairment and significant unmet medical need. Currently, treatment options remain limited for affected children and their families. The investigational gene therapy has also received PRIority MEdicines (PRIME) designation and Orphan Drug Designation from the European Medicines Agency, reflecting rarity and the seriousness of MPS IIIA and the significant unmet medical need experienced by affected patients and their families. These designations are intended to support the development and evaluation of medicines for serious conditions and rare diseases and should not be interpreted as an indication that marketing authorisation will be granted.

As an investigational advanced therapy medicinal product, the application will fall within the scope of the European Union's Joint Clinical Assessment (JCA) framework introduced under the EU Health Technology Assessment Regulation. The JCA is intended to support a coordinated clinical assessment process across EU Member States and represents a new component of the broader pathway to patient access.

The Company is also continuing discussions with health authorities in multiple regions and has initiated regulatory engagement activities with the UK's Medicines and Healthcare products Regulatory Agency (MHRA) and the Saudi Food and Drug Authority (SFDA) as part of its broader objective to pursue potential future geographic expansion.

About Sanfilippo Syndrome Type A

Sanfilippo syndrome Type A is an ultra-rare, fatal lysosomal storage disease that primarily affects the brain and is marked by rapid, progressive neurodegeneration beginning in early childhood. Children with Sanfilippo syndrome Type A typically experience progressive global developmental delay, followed by the loss of cognitive, language, and motor function, ultimately leading to early death. Sanfilippo syndrome Type A is estimated to affect approximately 3,000 to 5,000 patients in commercially accessible geographies, with a median life expectancy of 15 years. The disease is caused by a deficiency of the sulfamidase (SGSH) enzyme, which results in the accumulation of heparan sulfate substrate in cells and progressive damage to the central nervous system.

About rebisufligene etisparvovec

Rebisufligene etisparvovec is a single-dose intravenous AAV9 gene therapy designed to deliver a functional copy of the deficient enzyme gene that can express and replace the SGSH enzyme. Ultragenyx received FDA approval for rebisufligene etisparvovec on September 17^th 2026.

About Ultragenyx

Ultragenyx is a biopharmaceutical company committed to bringing novel therapies to patients for the treatment of serious rare and ultra-rare genetic diseases. The company has built a diverse portfolio of approved medicines and treatment candidates aimed at addressing diseases with high unmet medical need and clear biology, for which there are typically no approved therapies treating the underlying disease. The company is led by a management team experienced in the development and commercialization of rare disease therapeutics. Ultragenyx’s strategy is predicated upon time- and cost-efficient drug development, with the goal of delivering safe and effective therapies to patients with the utmost urgency.

Forward-Looking Statements and Ultragenyx's Use of Digital Media
Except for the historical information contained herein, this press release contains forward-looking statements, including statements regarding the EMA’s review of the Marketing Authorisation Application for rebisufligene etisparvovec (UX111); the potential timing and outcome of that review and any European Commission decision; the potential safety, efficacy and benefits of UX111; the Joint Clinical Assessment process and potential patient access in EU Member States; and Ultragenyx’s plans for regulatory engagement and potential expansion in other geographies. These statements are forward-looking statements within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995. These forward-looking statements involve substantial risks and uncertainties that could cause actual results to differ materially from those expressed or implied. Such risks and uncertainties include, among others, the possibility that the EMA or other health authorities request additional data, studies or manufacturing information, delay review, or decline to grant marketing authorisation or other approvals; that clinical data do not establish the safety and efficacy required for approval; that manufacturing, quality or supply issues arise; that the Joint Clinical Assessment or national pricing and reimbursement processes delay or limit patient access; and that engagement with authorities outside the EU does not result in submissions or approvals. PRIME and orphan designations, and EMA validation of the application, do not assure approval or patient access.

For further information about risks and uncertainties affecting Ultragenyx, see its Quarterly Report on Form 10-Q filed on August 5, 2026, and subsequent periodic reports filed with the SEC. Ultragenyx undertakes no obligation to update or revise these forward-looking statements, except as required by law

In addition to its SEC filings, press releases and public conference calls, Ultragenyx uses its investor relations website and social media outlets to publish important information about the company, including information that may be deemed material to investors, and to comply with its disclosure obligations under Regulation FD. Financial and other information about Ultragenyx is routinely posted and is accessible on Ultragenyx’s Investor Relations website (https://ir.ultragenyx.com/) and LinkedIn website (https://www.linkedin.com/company/ultragenyx-pharmaceutical-inc-/).

Contact
media@ultragenyx.com

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