The maximum dose proposed for this study is below the maximum dose for which long term clinical data is available in 2 patients (2800 mg/kg weekly for 3-5 years). Although individual clinicians have not always utilized an escalating rate of infusion, the reports of infusion related reactions in three patients suggest that this is an appropriate clinical strategy to mitigate the risk of such events and is consistent with dosing administration for other therapeutic agents. In the proposed study, treatment will be administered less frequently than has been undertaken in compassionate use. This longer dosing interval is supported by nonclinical data comparing the metabolism of cholesterol in non-human species with that in man; although a once weekly dosing interval was initially studied in man based on data in the mouse, HP-β-CD cholesterol metabolism/turnover in the mouse is 13-fold higher than in man which, in NPC, likely translates into a 13-fold slower accumulation of cholesterol in human cells compared with those of the mouse.Therefore, it is theorized that, given the slower cholesterol metabolism in humans, the dosing interval could be much less frequent in man than in mouse; however, based on what is known about cholesterol metabolism in humans and the pharmacokinetic and pharmacodynamic effect of HP-β-CD in the mouse, a dosing interval of 2 weeks in man is likely to be well within the therapeutic dosing interval and also minimizes the amount of infusions required to be administered.