Abstract
We conducted a phase I study investigating the efficacy, safety, and tolerability of ONO-2160, a newly developed levodopa pro-drug, and carbidopa compared with levodopa and carbidopa to stabilize levodopa plasma concentration fluctuations in Japanese patients with Parkinson's disease. In an open-label two-period design, patients (n = 12) with Parkinson's disease received levodopa and carbidopa for 3 days before 7 days of treatment with ONO-2160 and carbidopa. Patients were primarily evaluated using the Unified Parkinson's Disease Rating Scale Part III, a Parkinson's disease symptom diary, and analysis of adverse events. Pharmacokinetic analysis of plasma levodopa concentration was also performed. ONO-2160 and carbidopa therapy stabilized effective plasma levodopa concentration. No adverse events with safety concerns were observed. The combination of ONO-2160 and carbidopa produced a prolonged and stable plasma levodopa concentration with a reduction in Unified Parkinson's Disease Rating Scale Part III total scores. The combination was well tolerated, with no safety concerns, when administered to Japanese patients with Parkinson's disease.