A Phase I, First-in-Human, Healthy Volunteer Study to Investigate the Safety, Tolerability, and Pharmacokinetics of CVN424, a Novel G Protein-Coupled Receptor 6 Inverse Agonist for Parkinson's Disease.

CVN424 is a novel small molecule and first-in-class candidate therapeutic to selectively modulate GPR6, an orphan G-protein coupled receptor. Expression of GPR6 is largely confined to the subset of striatal projection neurons that give rise to the indirect (striatopallidal) pathway, important in the control of movement. CVN424 improves motor function in preclinical animal models of Parkinson's disease. Here, we report results of a phase 1, first-in-human study investigating the safety, tolerability, and pharmacokinetics of CVN424 in healthy volunteers. The study (NCT03657030) was randomized, double-blind, and placebo controlled. CVN424 was orally administered in ascending doses to successive cohorts as inpatients in a clinical research unit. Single doses ranged from 1 mg to 225 mg, and repeated (7 day) daily doses were 25, 75, or 150 mg. CVN424 peak plasma concentrations were reached within 2 h post-dose in the fasted state and increased with increasing dose. Dosing after a standardized high-fat meal reduced and delayed the peak plasma concentration, but total plasma exposure was similar. Mean terminal half-life ranged from 30 to 41 h. CVN424 was generally well tolerated: no serious or severe adverse effects were observed, and there were no clinically significant changes in vital signs or laboratory parameters. We conclude that CVN424, a nondopaminergic compound that modulates a novel therapeutic target, was safe and well tolerated. A phase 2 study in patients with Parkinson's disease is underway. SIGNIFICANCE STATEMENT: This is the first-in-human clinical study of a first-in-class candidate therapeutic. CVN424 modulates a novel drug target, GPR6, which is selectively expressed in a pathway in the brain that has been implicated in the motor dysfunction of patients with Parkinson's disease. This study paves the way for investigating this novel mechanism of action in patients with Parkinson's disease.