FDA Approves First Gene Therapy for Rare Immune Disorder Wiskott-Aldrich Syndrome, Expanding Treatment to Patients Aged 6 Months and Older

Washington, Dec. 9, 2025 — The U.S. Food and Drug Administration (FDA) has approved Waskyra (etuvetidigene autotemcel), a gene therapy developed by nonprofit organization Fondazione Telethon ETS, for the treatment of Wiskott-Aldrich Syndrome (WAS), a rare and life-threatening congenital immune deficiency. This marks the first FDA-approved gene therapy for WAS and expands the treatment indication to patients aged six months and older.

WAS is caused by mutations in the gene that encodes the WAS protein, leading to severe immune dysfunction manifested as recurrent infections, bleeding, eczema, and low platelet counts. Traditionally, allogeneic hematopoietic stem cell transplantation has been the mainstay of treatment but is limited by donor matching challenges and risk of complications. Waskyra uses gene-corrected autologous hematopoietic stem cells engineered ex vivo to express functional WAS protein and reconstitute the patient’s immune system.

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The FDA’s approval was supported by real-world evidence drawn from two open-label studies and an expanded access protocol involving 27 WAS patients. Data showed that treatment with Waskyra resulted in an approximate 93% reduction in serious infections and about 60% reduction in moderate to severe bleeding events, indicating substantial clinical benefit and manageable safety.

The agency emphasized the importance of continued long-term follow-up and careful safety monitoring in patients receiving gene therapies. Waskyra’s approval reflects the FDA’s commitment to facilitating access to innovative treatments for rare genetic diseases while ensuring patient safety.

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Industry Insight — Hillgene Perspective

The approval of Waskyra signals a pivotal advance in gene replacement therapies for inherited immune disorders, particularly as it opens treatment access to very young patients. This development underscores regulators’ increasing reliance on real-world evidence and long-term outcome data. For CDMOs and the broader manufacturing ecosystem, high-complexity gene correction products place heightened emphasis on viral vector quality, process consistency, and longitudinal stability analytics. Hillgene believes that as such treatments come to market, the industry will see growing investment in GMP-grade viral vector production, process reproducibility frameworks, and extended monitoring systems to meet evolving regulatory and clinical demands.

Source: Reuters, FDA approves first gene therapy for rare immune disorder, December 9, 2025.