Allopregnanolone as a Regenerative Treatment for Parkinson's Disease

This is an open-label, pilot clinical trial of allopregnanolone (Allo) as a regenerative treatment for Parkinson's disease. A total of 10 study participants will receive weekly infusions of Allo for 12 weeks. Participants will be male and female, age 40-80 years with a history of idiopathic, sporadic PD who have a Hoehn \& Yahr stage 1-4. Allo is a potent neuroregenerative agent that promotes proliferation of human neural stem cells and has the potential to function as a regenerative therapeutic to restore motor function in persons with PD. Results from several preclinical studies in rodent models of PD confirm improved motor function after Allo treatment. Primary Objective: To assess the feasibility of a large-scale trial to determine the efficacy of weekly infusions of Allo in in patients with Idiopathic sporadic PD. Secondary Objectives: To evaluate the safety and tolerability of weekly infusions of Allo in participants with idiopathic sporadic PD, and assess single-dose pharmacokinetics of allopregnanolone. Tertiary / Exploratory Objectives: To assess efficacy signals of weekly infusions of Allo in participants with idiopathic sporadic PD. * Determine target engagement of Allo using dopamine transporter (DaT) imaging and magnetic resonance imaging (MRI). * Evaluate effect of Allo on motor function tests. * Evaluate the effect of Allo on cognitive function tests and clinical ratings. * Compare response to Allo administration between APOE4 carriers and non-carriers.