An experimental drug appears to slow the progression of Niemann-Pick disease type C1 (NPC1), a fatal neurological disease, according to results of a clinical study led by researchers at the National Institutes of Health. The study appears in The Lancet.

NPC1 is a rare genetic disorder that primarily affects children and adolescents, causing a progressive decline in neurological and cognitive functions. The U.S. Food and Drug Administration has not approved any treatments for the condition.