Following a reexamination at the request of the product manufacturer, the European Medicines Agency’s Committee for Medicinal Products for Human Use concluded that the active substance of Aqneursa, levacetylleucine, could not be considered a new active substance.

This confirmed their earlier recommendation at their July 2025 meeting not to consider levacetylleucine as a new active substance, when the agency also recommended granting a marketing authorization in the EU for Aqneursa (levacetylleucine, IntraBio Ireland Ltd) for the treatment of neurologic manifestations of Niemann-Pick type C (NPC) disease.

Obtaining new active status is important for drug manufacturers, as it offers 10 years of protection against generic competition. Companies must show that their product contains a “chemical active substance that is not previously authorized” and is ”not related to any other authorized substances.” They must also demonstrate that the substance “differs significantly” in safety or efficacy.

Fatal Genetic Disorder

NPC is a rare, progressive, and fatal genetic disorder caused by mutations encoding lysosomal proteins that are essential for the intracellular transport and metabolism of body fats, including cholesterol. Over time, the cells of the central nervous system and body organs stop working. There are no curative therapies for NPC.

The course of the disease varies highly depending on the age of onset, but most NPC patients are children and die before the age of 20. 

Improvement In Neurologic Signs, Symptoms, and Functioning 

Aqneursa is indicated for the treatment of neurologic manifestations of Niemann-Pick type C (NPC) disease, in combination with miglustat, or as a monotherapy in patients where miglustat is not tolerated, in adults and children aged 6 years or older and weighing at least 20 kg.

The active substance, levacetylleucine, is a modified form of the amino acid leucine that targets underlying processes of neurologic dysfunction. While the mechanism of action of levacetylleucine is not yet fully understood, nonclinical studies have demonstrated that it corrects energy metabolism. This includes improved production of adenosine triphosphate, the main source of energy for cerebellar tissues and cells.

A randomized, double-blind, placebo-controlled, two-period crossover phase 3 study demonstrated that Aqneursa offered improvement in neurologic signs, symptoms, and functioning — measured using the scale for the assessment and rating of ataxia — in patients with NPC disease after 12 weeks of treatment compared with placebo.

The only adverse event causally related to treatment with Aqneursa — which is available as 1-g granules for oral suspension — is flatulence.

Rob Hicks is a retired National Health Service doctor. A well-known TV and radio broadcaster, he has written several books and has regularly contributed to national newspapers, magazines, and online publications. He is based in the United Kingdom.