In the Parent Study, Patients will be assessed during three study phases: a baseline period, a 6-week treatment period, and a 6-week post-treatment washout period. If within 6 weeks prior to the initial screening visit, a patient has received any of the prohibited medications defined in the eligibility criteria (irrespective of the preceding treatment duration) a wash-out study-run in of 6 weeks is required prior to the first baseline assessment. All patients will receive the study drug during the treatment period. For each individual patient, the Parent Study lasts for approximately 3.5 - 4 months during which there are 6 visits to the study site.~This Extension Phase allows patients who have completed the Parent Study to, at the discretion of the Principal Investigator (PI), continue treatment with N-Acetyl-L-Leucine (IB1001). Patients will receive treatment with IB1001 for two one-year treatment periods, separated by a 6-week washout. All patients will receive the study drug during the two one-year treatment periods. For each individual patient, the Extension Phase lasts for approximately 25.5 months, during which there are 6 visits to the study site.
This is a multinational, multicenter, open-label, rater-blinded prospective Phase II study which will assess the safety and efficacy of N-Acetyl-L-Leucine (IB1001) for the treatment of Niemann-Pick type C disease (NPC).~There are two phases to this study: the Parent Study, and the Extension Phase.~The Parent Study evaluates the safety and efficacy of N-Acetyl-L-Leucine (IB1001) for the symptomatic treatment of NPC.~The Extension Phase evaluates the long-term safety and efficacy of IB1001 for the neuroprotective, disease-modifying treatment of NPC.