PK, PD and Safety of Multiple Doses of V1512 Tablets in PD Patients Compared to Standard Levodopa/Carbidopa Oral Tablets

Inclusion Criteria: 1. Male or female, \>30 years of age of any race; 2. A Body Mass Index between 18.5 and 29.9 kg/m2 (inclusive); 3. Clinical diagnosis according to the Brain Bank diagnostic criteria of idiopathic Parkinson's Disease (2 of 3 cardinal symptoms - bradykinesia, rigidity, tremor -must be present, with a positive response to L-dopa); 4. Presence of fluctuations in motor performance with \>2 hours inclusive of daytime OFF episodes (not applicable for cohort 1 patients); 5. At least 1 hour delay to ON time with afternoon doses; 6. Discontinued use of COMT inhibitors (cathecol-o-methyl transferase) for at least 2 weeks prior to study entry (not applicable for cohort 3 patients); 7. Stable doses of dopamine agonists or selegiline for at least 2 weeks before entry into the study; 8. Stable comorbidity for 4 weeks; 9. Female patients must be of non-childbearing potential (post-menopausal or physically incapable of childbearing); 10. Willing and able to give informed consent according to national legal requirements prior to initiation of any study-related procedures Exclusion Criteria: 1. Clinically relevant abnormal vital sign values or safety laboratory data. 2. Patients who smoke and are unable to refrain from smoking during the in-clinic period 3. Diagnosis of atypical parkinsonism; 4. A history and/or the presence of gastro-intestinal disorders (or surgery) that could interfere with absorption of the test medication; 5. A history of intolerance or clinically relevant allergy to L-dopa and/or carbidopa taken in any formulation or combination; 6. A history of intolerance or clinically relevant allergy to entacapone or any ingredients of Comtan (cohort 3 patients only) 7. Any other condition which, in the opinion of the Investigator, would interfere with optimal participation in the study e.g. inability to complete patient diary; 8. Participation in any clinical study or receiving treatment with another investigational drug within 30 days or 5 half lives (whichever is longer) before the screening visit; 9. Blood donation within 3 months before study participation; 10. History of neuroleptic malignant syndrome (NMS) or NMS-like syndromes, or non-traumatic rhabdomyolysis; 11. Patients taking non-selective MAO inhibitors; 12. Patients with a history of, or clinical indication of, narrow angle glaucoma; 13. Patients with a history of, or clinical indication of, malignant melanoma; 14. Patients with a history of, or clinical indication of, depression or psychosis; 15. Patients taking iron containing medications (ferrous sulphate, ferrous gluconate)