Aqneursa (levacetylleucine)

Ataxia-telangiectasia (A-T) is an autosomal recessive disorder caused by mutations in the ATM gene. It causes progressive loss of muscle control and coordination (ataxia) that typically begins in early childhood, small dilated blood vessels (telangiectasias), immune deficiencies, and an elevated risk of cancer. A 2022 systematic review found no population-based prevalence study, and published estimates differ by source. GeneReviews gives an estimated prevalence of 1 to 9 per 100,000 and a reported incidence between 1 in 300,000 and 1 in 40,000. MedlinePlus Genetics gives 1 in 40,000 to 100,000 people worldwide. A European Respiratory Society statement gives 1 per 150,000 in Europe and 3 per million in the United Kingdom, and the Ataxia-Telangiectasia Society estimates approximately 170 cases in the United Kingdom and Ireland, a prevalence of approximately 1 in 400,000. IntraBio stated 1 in 40,000, 1 in 40,000 to 100,000, and approximately 1 in 70,000 in three releases during 2026. In the United States, approximately 350 children are known to the A-T Children's Project, and Quince Therapeutics, the developer of another investigational A-T treatment, cites approximately 4,600 diagnosed people from IQVIA claims data.

In classic A-T, ataxia first appears in the toddler years and most children use a wheelchair from about age 10 years. In a cohort of 57 individuals with variant A-T, 42 used a wheelchair, first obtained at a median age of 20 years. Median survival was 25 years in a prospective U.S. cohort and 19 years in a retrospective U.S. cohort. The Kaplan-Meier 20-year survival rate was 53.4% in a French cohort of 240 individuals and 52.6% in a Latin American cohort of 218 individuals. Chronic lung disease and cancer each account for about one-third of deaths, and GeneReviews states that most individuals with classic A-T do not live longer than age 30 years.

Before September 2026, no treatment was approved for A-T in any country. Published guidance recommends symptomatic and supportive care from a multidisciplinary team that includes neurology, pulmonology, immunology, rehabilitation medicine, nutrition, and physical, occupational, and speech-language therapy, and states that no treatment is known to slow or stop the neurological decline. A 2026 systematic review of 13 studies with 314 participants concluded that no intervention had demonstrated sustained efficacy in adequately powered controlled trials.