Aqneursa (levacetylleucine)

The FDA approved levacetylleucine on 18 September 2026 for ataxia in adults and pediatric patients with A-T weighing at least 15 kg and describes it as the first treatment approved for ataxia in A-T. The evidence is one randomized, double-blind, placebo-controlled crossover trial of 73 participants with 12 weeks of each treatment. The prescribing information reports a treatment effect of -0.6 (95% CI -0.9 to -0.2) on the 16-point fSARA, and the publication reports a treatment effect of -1.88 (95% CI -2.70 to -1.06) on the 40-point SARA, the protocol primary endpoint. The prescribing information gives no numerical SARA result and states that the fSARA results were supported by consistent results on the original SARA. Adverse reactions with an incidence of at least 5% and greater than placebo were fall, skin laceration, and urinary tract infection; the label has no contraindications and one warning, embryo-fetal toxicity.

The controlled comparison covers 12 weeks of treatment. Participants who crossed from levacetylleucine to placebo had a mean SARA increase of 1.81 points over the following 12 weeks, and efficacy and safety beyond 12 weeks depend on the open-label extension phase, which was ongoing at publication. Eligibility required an age of 4 years or older and a SARA score of 7 to 34, and 55 of 73 participants (75%) were White. The investigators state that the study was too short to investigate effects on immunological defects and oncological risks. An earlier randomized crossover trial in 16 participants found no significant effect of N-acetyl-L-leucine on the SARA, and the phase 2 trial IB1001-203 was terminated after 17 of approximately 39 planned participants were enrolled. No cost-effectiveness analysis, budget impact model, or health technology assessment in A-T has been published, and no source states a WAC announced with the A-T approval; the WAC reported at the 2024 introduction was $13,450 per carton of 28 packets, and a 2025 state Medicaid review listed $691,718.40 per year at 4 g per day.