Biomarker Validation for Niemann-Pick Disease, Type C: Safety and Efficacy of N-Acetyl Cysteine

Niemann-Pick Disease, type C (NPC) is an autosomal recessive lysosomal storage disease with progressive neurodegeneration. It is characterized by intracellular accumulation of cholesterol and glycosphingolipids. The age of onset is variable with cases manifesting from infancy to adulthood. Classically, initial neurological symptoms are observed in early to late childhood. Symptoms and signs of NPC include prolonged neonatal jaundice, splenomegaly, and various neurological manifestations, especially ataxia, dysmetria, dysarthria, vertical supranuclear gaze palsy and cognitive decline. Currently there are no approved therapies for NPC. A recent controlled study and a series of case reports suggest some efficacy for miglustat. Miglustat inhibits the biosynthesis of glycosphingolipids. The pathophysiological processes contributing to neurodegeneration in NPC have been intensively studied in NPC mouse models. Potential pathological processes include toxic effects of cholesterol or glycosphingolipid accumulation, deficient oxysterol production, peroxisomal dysfunction, mitochondrial dysfunction, perturbed intracellular calcium homeostasis, inflammation, induction of apoptosis, deficient neurosteroid synthesis, and increased oxidative stress. The degree to which each of these pathological processes contributes to the pathology of NPC is not known; however, the multiple processes involved suggest that combinatorial therapy addressing various aspects of this disorder will be necessary. A major impediment to the development of clinical trials for NPC has been the prior lack of outcome measures. Identifying biomarkers was a major goal of our NPC natural history trial (06-CH-0186). We now have identified multiple biochemical abnormalities in our cohort of patients that may prove useful as biomarkers in a therapeutic trial. The next step is to attempt to validate these potential biomarkers in a therapeutic trial. Thus in this protocol we plan to evaluate the safety and efficacy of N-acetylcysteine to improve a group of biomarkers related to increased oxidative stress. The goals of this protocol are: 1. To validate the use of biomarkers in a therapeutic trial for NPC. 2. To evaluate the safety of N-acetylcysteine in NPC patients. 3. To evaluate the efficacy of N-acetylcysteine to improve biomarkers associated with increased oxidative stress in NPC patients.