Three years of levacetylleucine (Aqneursa) continues to hold back Niemann-Pick disease type C. New extension data from the phase 3 IB1001-301 trial show that both adults and children on the drug experienced far less disease progression than historical untreated patients — and the drug has since earned a second FDA approval for a related rare condition.
Three years in, levacetylleucine is still delivering for Niemann-Pick patients
Long-term follow-up data from the phase 3 IB1001-301 trial, presented at the 2026 Child Neurology Society Annual Meeting, show that levacetylleucine (Aqneursa) continued to slow disease progression in both adults and children with Niemann-Pick disease type C (NPC) over 36 months. The drug, which became the first FDA-approved standalone therapy for NPC in September 2024, is showing durable long-term benefit.
Of the 39 participants who completed the 36-month extension visit, disease severity scores barely budged compared to what natural history data would predict for untreated patients — a striking difference that held up across both age groups and multiple measurement scales.
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Why it matters: NPC is a rare, progressive neurodegenerative disease with no other approved standalone treatments. These 3-year results reinforce levacetylleucine's disease-modifying potential and are especially meaningful for pediatric patients, where slowing progression early can significantly impact quality of life. The drug has also recently received FDA approval for ataxia-telangiectasia, broadening its reach in rare neurological disease.
