Intravenous 2-hydroxypropyl-β-cyclodextrin (Trappsol® Cyclo™) demonstrates biological activity and impacts cholesterol metabolism in the central nervous system and peripheral tissues in adult subjects with Niemann-Pick Disease Type C1: Results of a phase 1 trial

Background: Niemann-Pick Disease Type C1 (NPC1) is a disorder of intracellular cholesterol and lipid trafficking that leads to the accumulation of cholesterol and lipids in the late endosomal/lysosomal compartment, resulting in systemic manifestations (including hepatosplenomegaly and lung infiltration) and neurodegeneration. Preclinical studies have demonstrated that systemically administered 2-hydroxypropyl-beta-cyclodextrin (HP beta CD; Trappsol (R) Cyclo (TM)) restores cholesterol metabolism and homeostasis in peripheral organs and tissues and in the central nervous system (CNS). Here, we assessed the safety, pharmacokinetics, and pharmacodynamics of HP beta CD in peripheral tissues and the CNS in adult subjects with NPC1. Methods: A Phase 1, randomized, double-blind, parallel group study enrolled 13 subjects with NPC1 who received either 1500 mg/kg or 2500 mg/kg HP beta CD intravenously every 2 weeks for a total of 7 doses (14 weeks). Subjects were 18 years or older, with a confirmed diagnosis of NPC1 and evidence of systemic involvement on clinical assessment. Pharmacokinetic evaluations in plasma and cerebrospinal fluid (CSF) were performed at the first and seventh infusions. Pharmacodynamic assessments included biomarkers of systemic cholesterol synthesis (serum lathosterol) and degradation (serum 4 beta-hydroxycholesterol), secondary sphingomyelin storage (plasma lysosphingomyelin-509, now more accurately referred to as N-palmitoyl-O-phosphocholineserine [PPCS]), and CNS-specific biomarkers of neurodegeneration (CSF total Tau) and cholesterol metabolism (serum 24(S)-hydroxycholesterol [24(S)-HC]). Safety monitoring included assessments of liver and kidney function, infusion related adverse events, and hearing evaluations. Results: Ten subjects completed the study, with 6 at the 1500 mg/kg dose and 4 at the 2500 mg/kg dose. One subject withdrew following the first infusion after experiencing hypersensitivity pneumonitis, and 2 subjects withdrew after meeting a stopping rule related to hearing loss. Overall, HP beta CD had an acceptable safety profile. The observed pharmacokinetic profile of HP beta CD was similar following the first and seventh infusions, with a plasma half-life of 2 h, a maximum concentration reached at 6 to 8 h, and no evidence of accumulation. Serum biomarkers of cholesterol metabolism showed reduced synthesis and increased degradation. Compared to Baseline, filipin staining of liver tissue showed significant reductions of trapped unesterified cholesterol at both dose levels at Week 14. Plasma PPCS levels were also reduced. HP beta CD was detected at low concentrations in the CSF (maximum, 33 mu M) at both dose levels and persisted longer in CSF than in plasma. Total Tau levels in CSF decreased in most subjects. Serum levels of 24(S)-HC, a cholesterol metabolite from the CNS that is exported across the blood-brain barrier and into the circulation, decreased after both the first and seventh doses. Hence, pharmacodynamic assessments in both peripheral and CNS-related tissue show target engagement. While not the aim of the study, subjects reported favorable impacts on their quality of life. Conclusions: The plasma pharmacokinetics and pharmacodynamics of HP beta CD administered at two intravenous dose levels to subjects with NPC1 were comparable to those observed in preclinical models. HP beta CD cleared cholesterol from the liver and improved peripheral biomarkers of cholesterol homeostasis. At low CSF concentrations, HP beta CD appeared to be pharmacologically active in the CNS based on the increased efflux of 24(S)-HC and reduction in CSF total Tau, a biomarker of CNS neurodegeneration. These data support the initiation of longer-term clinical trials to evaluate the safety and efficacy of intravenous HP beta CD in subjects with NPC1. (C) 2022 The Authors. Published by Elsevier Inc.

Automated summary

This study evaluated the safety, pharmacokinetics, and pharmacodynamics of HP beta CD in adult subjects with NPC1. Results showed that HP beta CD cleared cholesterol from the liver and improved peripheral biomarkers of cholesterol homeostasis, while also demonstrating pharmacological activity in the CNS.