This is a multicentre, open-label extension study to evaluate the long-term safety, tolerability, and efficacy of Perampanel (E2007) as an adjunctive therapy in levodopa treated PD subjects with motor fluctuations. All subjects who have completed E2007-E044-213 or E2007-G000-309 will be candidates for entering this extension trial, provided that they meet the inclusion/exclusion criteria and have completed the core study, up to and including the final efficacy visit.