A Safety, Tolerability, and Plasma Concentration Study of Levodopa/Carbidopa Subcutaneous Solution (ND0612) in Parkinson's Disease (PD) Patients

Main Inclusion Criteria: * Men and women with idiopathic Parkinson's disease * Subjects must experience motor fluctuations associated with LD/CD dosing * Modified Hoehn and Yahr stage \< 5 * Subjects must be taking optimized and stable levodopa/dopa decarboxylase inhibitor therapy * Women must be postmenopausal, surgically sterilized, or using adequate birth control. Women of childbearing potential must have a negative pregnancy test (serum beta-HCG) at screening. * Subjects must be age 30 or older. * Subjects must be willing and able to give informed consent. Main Exclusion Criteria: * Subjects with a clinically significant or unstable medical or surgical condition * Subjects with clinically significant psychiatric illness. * Pre-menopausal women, not using birth control method. * Subjects who have taken experimental medications within 60 days prior to baseline. * Subject who have undergone a neurosurgical intervention for Parkinson's disease (e.g., pallidotomy, thalamotomy, transplantation and deep brain stimulation).