Waskyra (etuvetidigene autotemcel)

A one-time gene therapy made from the patient's own blood stem cells, given as an infusion into a vein at a qualified treatment center after reduced-intensity chemotherapy with busulfan and fludarabine. The FDA approved it on December 9, 2025 as the first gene therapy for Wiskott-Aldrich syndrome (WAS), for patients 6 months and older who need a stem cell transplant but have no suitable HLA-matched related donor. It is the first cell or gene therapy the FDA has approved from a non-profit applicant, the Italian charity Fondazione Telethon.

Wiskott-Aldrich syndrome is caused by changes in the WAS gene, which makes the WAS protein (WASP). WASP organizes actin, the internal scaffolding that blood and immune cells need to move, fight infection and form normal platelets. To make Waskyra, doctors collect the patient's own blood-forming stem cells, and a lab adds working copies of the WAS gene using a lentiviral vector, a disabled virus that places the gene into the cells' DNA. After conditioning chemotherapy, the corrected cells are infused back, settle in the bone marrow and produce blood and immune cells that make WASP. In the studies, gene-corrected cells were found in all evaluated patients for up to 9 years, and restored WASP led to higher platelet counts and better immune function.

Waskyra has no boxed warning. It should not be used in people allergic to its ingredients, people who had a donor stem cell transplant in the past 6 months or still have donor cells, people who already had stem cell gene therapy, or people who cannot have the mobilization or conditioning drugs. The studies had no placebo group, and side effects were counted during conditioning and the first year, so many reflect rituximab, chemotherapy and the disease itself; no adverse reactions were attributed to the gene therapy. Among 27 treated patients, the most common were rash (85%), respiratory infections (67%), catheter-related infections (59%), diarrhea (59%), liver injury (59%), petechiae, tiny bleeding spots under the skin (59%), vomiting (44%), anemia (41%), fever (41%), conjunctivitis (37%), head injury (37%), catheter site problems (37%), nosebleeds (33%), cytomegalovirus infection (30%) and febrile neutropenia (26%)^[1]. There were 45 serious adverse reactions in 21 patients, most often catheter-related infections and bacterial or viral infections. A patient died about 4.5 months after infusion from neurological decompensation, and a thyroid cancer found 5 years after treatment in another patient did not contain the vector^[1]. The label warns about allergic and infusion reactions to the DMSO preservative, failure of the new cells to take, severe low blood counts lasting several weeks, serious infections, liver veno-occlusive disease and a lifelong risk of blood cancer from the vector inserting into DNA. Treated patients can test falsely positive on PCR tests for HIV and should never donate blood, organs, tissues or cells^[1].

Waskyra is given once, at a qualified treatment center. Stem cells are first moved into the blood with G-CSF and plerixafor and collected by apheresis, and a back-up supply of at least 3 million CD34+ cells per kg is frozen before treatment. About 22 days before the infusion, patients receive rituximab to clear B cells and lower the risk of an Epstein-Barr virus-driven lymph disorder, followed by reduced-intensity conditioning chemotherapy with busulfan and fludarabine. An antihistamine such as chlorpheniramine is given 15 to 30 minutes before the infusion. The minimum dose is 7 million CD34+ cells per kg, infused through a central venous line; each bag is given within 30 minutes, at no more than 5 mL per kg per hour, and within 2 hours of thawing. Blood pressure, heart rate and oxygen levels are checked about every 10 minutes during the infusion and every hour for 3 hours after^[1]. In the studies, rituximab was a single dose of 375 mg per square meter of body surface, busulfan was given as 8 doses over 3 days and fludarabine totaled 60 mg per square meter^[1]. UCSF Benioff Children's Hospitals became the first US qualified treatment center for Waskyra in September 2026, with more centers expected^[6].

Yes, Etuvetidigene autotemcel (Waskyra) is FDA approved (2025) for the treatment of Wiskott-Aldrich Syndrome.

On September 28, 2026, UCSF Benioff Children's Hospitals in San Francisco became the first US qualified treatment center contracted to give Waskyra, and Fondazione Telethon and Orphan Therapies said more centers are expected in the coming months. Ask your immunology team about a referral.

Waskyra is approved for children 6 months and older and adults who have a mutation in the WAS gene, for whom a stem cell transplant is appropriate, and who have no suitable HLA-matched related donor. It cannot be given to people who had a donor transplant in the past 6 months or still have donor cells, or who already had stem cell gene therapy.

In the 26 patients included in the main efficacy analysis, severe infections fell from 2.0 to 0.2 per patient-year, comparing months 6 to 18 after treatment with the year before. Moderate and severe bleeding fell by 60% in the first year, and most patients had no moderate or severe bleeding after 4 years. No trial has compared Waskyra with a donor stem cell transplant.