There is solid scientific rational and preclinical data supporting a clinical trial of isradipine CR as a potential disease modifying agent in early PD. Human pharmacokinetic data demonstrate that it is feasible to achieve the serum concentrations in humans that were neuroprotective in preclinical models with the FDA approved dosage range. Pilot data demonstrate acceptable tolerability of isradipine CR in the PD population. Tolerability is inversely proportional to the dosage dependent. Considering that tolerability of isradipine CR is inversely proportional to the dosage exposure, it is essential to proceed with the dose selection tolerability study in preparation for the future efficacy trials.~The tolerability, defined as the ability to complete the study, of three dosages of isradipine CR relative to placebo in subjects with early Parkinson's disease will be examined first. The dosage that is tolerable and demonstrates preliminary efficacy will be evaluated further in the future pivotal efficacy studies.
The primary purpose of this study is to establish a dosage of isradipine CR that is tolerable and demonstrates preliminary efficacy for utilization in future pivotal efficacy studies.