In a landmark development for rare disease treatment, the U.S. Food and Drug Administration (FDA) has approved Waskyra (etuvetidigene autotemcel), the first gene therapy for Wiskott-Aldrich syndrome (WAS), a life-threatening genetic immunodeficiency that primarily affects young boys.

The approval follows decades of scientific work led by the San Raffaele Telethon Institute for Gene Therapy (SR-Tiget) in Milan, alongside a recent positive opinion from the European Medicines Agency’s Committee for Medicinal Products for Human Use.

Breakthrough for a Rare and Severe Disorder

Wiskott-Aldrich syndrome is caused by mutations in the WAS gene, resulting in dysfunctional immune and blood cells. Children with the disorder face recurrent infections, bleeding complications, eczema, and a higher risk of autoimmune disease and lymphoma. The condition affects an estimated 1 in 250,000 male births, and until now, treatment options have been limited to supportive care or bone marrow transplantation—procedures that carry significant risks and depend on matched donors.

How Waskyra Works

Waskyra is an ex vivo autologous gene therapy. It uses a patient’s own stem cells, which are collected, genetically corrected with a lentiviral vector carrying the functional WAS gene, and then reinfused after chemotherapy prepares the bone marrow.

Clinical trials conducted at IRCCS Ospedale San Raffaele showed that the therapy reduces severe bleeding and infections, offering a potentially life-changing alternative for patients who lack a suitable stem cell donor.

Decades of Research Behind the Approval

Fondazione Telethon, the non-profit research foundation behind the therapy, described the FDA approval as a milestone for scientific innovation and the rare disease community.

“The FDA’s approval of Waskyra is an extraordinary achievement—not only for Italian research and for Fondazione Telethon, but for the global rare disease community,” said Ilaria Villa, CEO of the foundation. “It confirms the value of a patient-centered model that turns research into real treatments, especially where the market fails to act.”

Dr. Alessandro Aiuti, Deputy Director of Clinical Research at SR-Tiget and a leading figure in WAS therapy development, called the approval a significant moment for caregivers, clinicians, and families alike.

“Seeing years of scientific research and dedication translate into real therapeutic opportunities for people gives profound meaning to our work,” he said.

A First for Non-Profit–Led Gene Therapy

Telethon is the first non-profit organisation to shepherd an ex vivo gene therapy from early laboratory work through to regulatory approval. The achievement sets a precedent for how charitable foundations can drive innovation for diseases that lack commercial incentives.

FDA approval solidifies Telethon’s position as a global leader in rare genetic research and advanced therapies.

Eligibility and Safety Information

Waskyra is approved for children aged six months and older, as well as adults, who have a confirmed WAS gene mutation and are eligible for stem cell transplantation but lack a matched related donor.

While the gene therapy itself did not cause adverse reactions in trials, doctors note that the preparatory steps—including stem cell mobilisation, apheresis, rituximab therapy, and reduced-intensity chemotherapy—carry known risks.

Patients and physicians are encouraged to report any adverse effects associated with treatment to the FDA through its MedWatch programme.