An Open-label Safety Study of Pimavanserin in Parkinson's Disease Patients

Inclusion Criteria- * Patients of any age, male or female with a clinical diagnosis of idiopathic Parkinson's disease, who participated in a previous (Phase II) clinical trial that evaluated pimavanserin * Patients who may, in the opinion of the treating physician, benefit from continued therapy with pimavanserin * Patient is willing and able to provide consent Exclusion Criteria- * Female patient of childbearing potential * Patient has a clinically significant concurrent medical illness * Patient is judged by the treating physician to be inappropriate for the study.