Abeona Therapeutics® Congratulates Ultragenyx on U.S. FDA Approval of FAYUVI™ Gene Therapy for Sanfilippo Syndrome Type A (MPS IIIA)

- FDA approval represents a monumental milestone for patients with MPS IIIA and validates Abeona’s foundational R&D and clinical development efforts -

- Ultragenyx successfully brought a life-changing therapy across the finish line for MPS IIIA patients and families -

CLEVELAND, Sept. 18, 2026 (GLOBE NEWSWIRE) -- Abeona Therapeutics Inc. (Nasdaq: ABEO), a commercial-stage biopharmaceutical company developing genetic medicines for serious diseases with high unmet need, today congratulated Ultragenyx Pharmaceutical Inc., on the U.S. Food and Drug Administration (FDA) approval of FAYUVI™ (rebisufligene etisparvovec-hopf), also known as UX111, a gene therapy for the treatment of patients with Sanfilippo syndrome type A (mucopolysaccharidosis IIIA, or MPS IIIA), a rare and progressive neurodegenerative lysosomal storage disorder.

FAYUVI originated from pioneering research conducted by Drs. Haiyan Fu and Douglas McCarty at The Ohio State University and Nationwide Children's Hospital and was subsequently advanced through clinical development by Abeona Therapeutics as ABO-102. In 2022, Abeona entered into an out-licensing agreement with Ultragenyx granting the company global development and commercialization rights to the program.

“FDA approval of FAYUVI represents an extraordinary milestone for patients and families affected by Sanfilippo syndrome type A, a devastating disease that has lacked effective therapeutic options,” said Vish Seshadri, Chief Executive Officer of Abeona Therapeutics. “The journey to this achievement is a testament to years of scientific innovation and determination across multiple organizations. Abeona was privileged to help advance this program from its academic origins into clinical development, generating the foundational data that supported its continued progress. We are grateful that Ultragenyx continued its advancement through regulatory approval and commend everyone involved in bringing this important therapy to patients.”

The approval of FAYUVI also represents a meaningful value-creation event for Abeona. Pursuant to its licensing agreement with Ultragenyx, Abeona is eligible to receive certain commercial milestone payments and royalties tied to future product sales.

About the FAYUVI development history
Abeona initially advanced the FAYUVI program through critical preclinical and clinical development stages, demonstrating proof-of-concept and establishing safety and efficacy profiles in clinical studies. To ensure the program received the substantial resources required for late-stage development, regulatory filing, and eventual commercialization, Abeona out-licensed the asset to Ultragenyx in May 2022.

About MPS IIIA (Sanfilippo Syndrome Type A)
MPS IIIA is a devastating, progressive, and fatal pediatric neurodegenerative disease caused by a deficiency of the enzyme N-sulfoglucosamine sulfohydrolase, (SGSH), which leads to the accumulation of heparan sulfate in cells throughout the body, particularly in the central nervous system. Children with MPS IIIA experience severe developmental regression, loss of motor skills, and premature death, creating an urgent, high-unmet medical need. FAYUVI is designed to deliver a functional copy of the SGSH gene to the central nervous system via an AAV9 viral vector, addressing the root genetic cause of the disease.

About Abeona Therapeutics
Abeona Therapeutics Inc. is a commercial-stage biopharmaceutical company developing cell and gene therapies for serious diseases. Abeona’s ZEVASKYN^® (prademagene zamikeracel) is the first and only autologous cell-based gene therapy for the treatment of wounds in adult and pediatric patients with recessive dystrophic epidermolysis bullosa (RDEB). The Company’s fully integrated cell and gene therapy cGMP manufacturing facility in Cleveland, Ohio, serves as the manufacturing site for ZEVASKYN commercial production. The Company’s development portfolio features ABO-701 (PSMA-SIR-T™), a potentially first-in-class engineered T-cell therapy targeting PSMA, engineered to overcome the core failures of cell therapies in solid tumors. For more information, visit www.abeonatherapeutics.com.

ZEVASKYN^®, Abeona Assist^®, Abeona Therapeutics^®, and their related logos are trademarks of Abeona Therapeutics Inc.

Forward-Looking Statements
This press release contains certain statements that are forward-looking within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, and that involve risks and uncertainties. We have attempted to identify forward-looking statements by such terminology as “may,” “will,” “believe,” “anticipate,” “expect,” “intend,” “potential,” and similar words and expressions (as well as other words or expressions referencing future events, conditions or circumstances), which constitute and are intended to identify forward-looking statements. Actual results may differ materially from those indicated by such forward-looking statements as a result of various important factors, numerous risks and uncertainties, including but not limited to our ability to maintain existing and obtain additional regulatory approvals of ZEVASKYN® and any future product candidates; our ability to successfully commercialize and market ZEVASKYN® and any future product candidates, if approved, and the timing of any commercialization and marketing efforts; our ability to manufacture sufficient batches of ZEVASKYN® to meet demand; our ability to manufacture ZEVASKYN® batches that meet certain product release specifications that were required by FDA at the time of BLA approval and implemented based on a limited clinical dataset; the FDA’s willingness to revise such release specifications to reflect real-world manufacturing experience; our ability to manufacture from provided biopsy material a ZEVASKYN® batch for which revenue may ultimately be recognized, which depends on such factors as qualified treatment centers obtaining biopsy samples from ZEVASKYN® patients of sufficient quality to act as starting material for manufacturing ZEVASKYN®, patient-to-patient variability in cell growth during the ZEVASKYN® manufacturing process, patient health deterioration in close proximity to ZEVASKYN® treatment such that treatment is no longer possible, and expiration of ZEVASKYN®’s 84-hour shelf-life before surgical application of ZEVASKYN® can be performed; our ability to activate additional qualified treatment centers to administer ZEVASKYN® on patients; the ability of qualified treatment centers to enroll patients for treatment or administer ZEVASKYN® on patients; the ability of our partners to obtain FDA approval and generate revenue from partnered programs and our ability to collect associated royalty and milestone payments; our ability submit an investigational new drug application for ABO-701 and enroll patients in new clinical trials; our ability to access additional financial resources and/or our financial flexibility to reduce operating expenses if required; our ability to obtain additional equity funding from current or new stockholders; the potential impact of unpredicted changes in the structure and/or administration of the United States government or its agencies; our ability to out-license technology and/or other assets, deferring and/or eliminating planned expenditures, restructuring operations and/or reducing headcount, and sales of assets; the dilutive effect that raising additional funds by selling additional equity securities would have on the relative equity ownership of our existing investors, including under our existing at-the-market sale agreement; the outcome of any interactions with the FDA or other regulatory agencies relating to any of our products or product candidates; our ability to continue to secure and maintain regulatory designations for our product candidates; our ability to develop manufacturing capabilities compliant with current good manufacturing practices for our product candidates; our ability to manufacture cell and gene therapy products and produce an adequate product supply to support clinical trials and potentially future commercialization; the rate and degree of market acceptance of our product candidates for any indication once approved; our ability to meet our obligations contained in license agreements to which we are party; and macroeconomic uncertainty resulting from changes to U.S. trade policy, including current or future tariffs or other trade restrictions.