Inclusion Criteria

• Male or female ≥ 18 years of age
• Clinical diagnosis of Idiopathic Parkinson's Disease, consistent with UK Brain Bank Criteria
• Clinically meaningful response to L-Dopa with well-defined early morning "OFF" episodes, as determined by the Investigator
• Receiving stable doses of L-Dopa/carbidopa (immediate or CR) administered at least 4 times per day OR Rytary™ administered 3 times per day, for at least 4 weeks before the initial screening visit
• No planned medication change(s) or surgical intervention anticipated during the course of study
• Patients must experience at least one well defined "OFF" episode per day with a total daily "OFF" time duration of ≥ 2 hours during the waking day, based on patient self-assessment
• Stage III or less on the modified Hoehn and Yahr scale in the "ON" state
• MMSE score > 25

Exclusion Criteria

• Must not meet any of the following exclusion criteria
  • Atypical or secondary parkinsonism
  • Previous treatment with any of the following
    • a neurosurgical procedure for PD
    • continuous s.c. apomorphine infusion
    • or Duodopa/Duopa
  • Treatment with any form of s.c. apomorphine within 7 days prior to the initial screening visit (SV1)
    • Patients that stopped s.c. apomorphine for any reason other than systemic safety concerns or lack of efficacy may be considered
  • Contraindications to
    • APOKYN®, or hypersensitivity to apomorphine hydrochloride or any of the ingredients of APOKYN® (notably sodium metabisulfite)
    • Tigan® trimethobenzamide hydrochloride (patients from US sites only)
    • Domperidone (patients from non-US sites only)
  • Participation in a clinical trial within 30 days prior to the initial screening visit (SV1)
  • Currently taking
    • Selective 5HT3 antagonists (i.e., ondansetron, granisetron, dolasetron, palonosetron, alosetron)
    • Dopamine antagonists (excluding quetiapine or clozapine)
    • Dopamine depleting agents
  • Drug or alcohol dependency in the past 12 months
  • History of malignant melanoma
  • Clinically significant medical, surgical, or laboratory abnormality in the opinion of the Investigator
  • Major psychiatric disorder including, but not limited to, dementia, bipolar disorder, psychosis, or any disorder that, in the opinion of the Investigator, requires ongoing treatment that would make study participation unsafe or make treatment compliance difficult
  • History of clinically significant hallucinations during the past 6 months
  • History of clinically significant impulse control disorder
  • Dementia that precludes providing informed consent or would interfere with participation in the study