NPC is a rare, relentlessly progressive, neurological disease and associated with serious morbidity and shortened life expectancy. The purpose of this Expanded Access Program is to provide early access to arimoclomol for patients with Niemann-Pick Type C disease who, in the opinion and the clinical judgement of the treating physician, may benefit from treatment with arimoclomol. Participants will receive treatment with arimoclomol until their doctor finds it does not help them anymore, they withdraw, or the study is stopped for any reason.