A Study to Assess the Safety and Efficacy of the of the Gastric-retentive AP-CD/LD in Advanced Parkinson's Patients

Main Inclusion Criteria:

1. Subjects must be approved for suitability by an Enrollment Approval Committee

2. Able and willing to give written (signed and dated) informed consent and adhere tovisit schedule and available to complete the study

3. Men or women 30 years of age and higher at initial screening assessment. (For the 100subjects who enter the Gastroscopy sub study, the age limits are 30-80 years of age,inclusive, at initial screening assessment)

4. Diagnosed with Parkinson's disease, consistent with UK brain bank criteria

5. Has a good response to Levodopa and is taking at least 4 doses of a Levodopacontaining medication (or 3 doses of Rytary) per day during waking hours (notincluding nighttime long acting levodopa) at a stable dose for at least 28 days priorto initial screening assessment

6. Other Anti-PD treatment (such as dopamine agonists, selective MAO-B inhibitors,anticholinergic agents or Amantadine) are permitted if stable for at least 28 daysprior to study entry and provided they are not anticipated to be changed during thecourse of the study

7. Total LD immediate release daily dose of 400 mg to 1300 mg or equivalent prior toinitial screening assessment. Specifically for Rytary, doses up to 1755 mg daily areacceptable.

8. Able to complete a Hauser Home Diary and can tell the difference between "On" and "Off" time

9. Achieved at least 75% diary concordance with an approved site rater in a 4-hourtraining session including at least one "Off time" assessment

10. Returned a valid 2-day practice diary after training has been completed.

11. At least 2.5 hours "Off time" per day during waking hours on Screening 2-day PracticeHauser Home Diary (morning akinesia should be incorporated into the total "Off time"assessment).

12. Other than PD, the subject is in satisfactory health, as assessed by physicalexamination and screening tests. No clinically significant medical, psychiatric orlaboratory abnormality that could compromise safety or interfere with study proceduresin the opinion of either the investigator or the Enrollment ApprovalCommittee/Sponsor.

13. Living in an area that is within 3 hours driving distance from the study site or iswilling to stay in such a place the night before each study visit

Main Exclusion Criteria:

1. Participation in another drug clinical trial within 28 days prior to initial screeningassessment (calculated from the previous study's last dosing date)

2. Atypical Parkinsonism (subjects with Parkinsonian features caused by disorder such asmultiple system atrophy, progressive supranuclear palsy, dementia with Lewy bodies ormultiple brain infarcts)

3. Clinically significant cardiac, pulmonary, hepatic or renal disease or other conditionor any major complication/illness which contraindicates his/her participation in theopinion of either the investigator or the Enrollment Approval Committee/Sponsor.

4. Severe dyskinesia in the opinion of either the investigator or the Enrollment ApprovalCommittee.

5. Treatment with non-selective monoamine oxidase (MAO) inhibitors during the last 28days prior to initial screening assessment or planning to take during studyparticipation

6. Previous or planned neurosurgical treatment for Parkinson's Disease (e.g., proceduresincluding ablation or deep brain stimulation) during the course of the study

7. Significant cognitive impairment as defined by the Mini-Mental State Examination (MMSE) score < 26.

8. Clinically significant psychiatric illness, including major depression (HamiltonDepression Rating Scale-17 ≥14). Subjects with a lifetime history of suicidal attempt (including an active attempt, interrupted attempt or aborted attempt)

9. Current or previous treatment for more than 1 month within the past 2 years with anyneuroleptic drug (antipsychotic) or any other drug with anti-dopaminergic properties (e.g. metoclopramide, domperidone)

10. Currently experiencing or any known history of psychosis or delusions within 2 yearsprior to Screening.

11. Known history of substance abuse within the past 2 years

12. Moderate or greater level of alcohol consumption

13. Unable to swallow large pills (e.g., large vitamin pills)

14. History of Melanoma or suspicious skin lesion which could be a Melanoma

15. Narrow-angle Glaucoma

16. History of small bowel or gastric surgery (Including PEG-J placement forDuopa/Duodopa) or bowel obstruction, diagnosis of small bowel narrowing, diagnosis ofCrohn's disease, or frequent nausea or emesis, regardless of etiology, (Previousappendectomy or hernioplasty will not be exclusionary).

17. Active peptic ulcer disease or a history of peptic ulcer or upper GI bleeding

18. Regular use of opioids (Intermittent opioid use is not exclusionary)

19. Symptomatic gastroparesis with frequent vomiting (at least once a week)

20. Concomitant use of NSAIDs and oral steroids within the past 28 days

21. Allergy to the study drug or any of its excipients, or to Yellow Dye #5 (tartrazine)

22. Women who are pregnant or nursing. Women of childbearing potential who are not willingto use a medically acceptable method of contraception.