Patient description: The patient is a 55-year-old man who was recently diagnosed with Parkinson's disease. He is complaining of slowness of movement and tremors. His disease is ranked as mild, Hoehn-Yahr Stage I. His past medical history is significant for hypertension and hypercholesterolemia. He lives with his wife. They have three children. He used to be active with gardening before his diagnosis. He complains of shaking and slow movement. He had difficulty entering through a door, as he was frozen and needed guidance to step in. His handwriting is getting smaller. He is offered Levodopa and Trihexyphenidyl. He is an alert and cooperative man who does not have any signs of dementia. He does not smoke or use any illicit drugs.

Clinical trial eligibility criteria: eligible ages (years): 30.0-75.0,  Parkinson's Disease Male or female of non-childbearing potential (by reason of surgery or postmenopausal) Aged between 30 and 75 years, inclusive A diagnosis of PD according to the UK PDS Brain Bank diagnostic (bradykinesia and at least one of the following: muscular rigidity, rest tremor and postural instability) Predictable signs of end-of-dose deterioration despite "optimal" levodopa/carbidopa or levodopa/benserazide therapy Been treated with a stable regimen of 3 to 8 doses of standard release 100 mg/25 mg levodopa/carbidopa or 100 mg/25 mg levodopa/benserazide per day within at least 1 week prior to randomisation Modified Hoehn and Yahr stage of less than 5 in the off-state Mean duration of OFF stage ≥ 1.5 h during waking hours (based on historical information) Concomitant anti-Parkinsonian medication (other than apomorphine, entacapone or tolcapone) in stable doses for at least 4 weeks prior to randomisation Results of clinical laboratory tests acceptable by the investigator (not clinically significant for the well-being of the subject or for the purpose of the study) Able and willing to give written informed consent  Non-idiopathic parkinsonism (atypical parkinsonism, symptomatic parkinsonism, Parkinson-plus syndrome) Treated with levodopa/carbidopa or levodopa/benserazide in a 10:1 ratio, or with levodopa/carbidopa in a controlled-release formulation Treated with entacapone, tolcapone, neuroleptics, antidepressants (except serotonin-specific reuptake inhibitors or imipramines [desipramine, imipramine, clomipramine and amitriptyline]), monoamine oxidase inhibitors (except selegiline up to 10 mg/day in oral formulation or 1.25 mg/day in buccal absorption formulation or rasagiline up to 1 mg/day) or antiemetics (except domperidone) within 4 weeks prior to randomisation Treated with apomorphine within 7 days prior to randomisation Treated with any investigational product within 2 months prior to randomisation (or within 5 half-lives, whichever is longer) A psychiatric or any medical condition that might place him/her at increased risk or interfere with assessments Known hypersensitivity to any of the ingredients of the investigational products A history of abuse of alcohol, drugs or medications within the last 2 years A clinically relevant ECG abnormality A history or current evidence of heart disease, including but not limited to myocardial infarction, angina, congestive heart failure and cardiac arrhythmia