A Study to Evaluate the Safety and Efficacy of IPX203 in Parkinson's Disease Patients With Motor Fluctuations

This is a multicenter, randomized, double-blind, double-dummy, active-controlled,
parallel-group study. The study will consist of a 3-week, open-label IR CD-LD dose adjustment
period; a 4-week, open-label period for conversion to IPX203; followed by a 13-week
double-blind treatment period with subjects randomized in a 1:1 ratio, stratified by center,
to receive either IPX203 (with matching IR CD-LD placebo) or IR CD-LD (with matching IPX203
placebo). Approximately 510 subjects will be enrolled to randomize 420 subjects.

Inclusion Criteria:

- Male or female subjects diagnosed at age ≥ 40 years with PD, consistent with the
United Kingdom Parkinson's Disease Society Brain Bank Diagnostic Criteria and who are
being treated with stable regimens of CD-LD but experiencing motor fluctuations.

- Able to provide written informed consent prior to the conduct of any study-specific
procedures.

- Female subjects of childbearing potential must have a negative urine pregnancy test at
Screening Visit.

- Negative urine screen for drugs of abuse and negative alcohol breath test at
Screening.

- Hoehn and Yahr Stages 1, 2, 3, or 4 in the "On" state (part of Movement Disorders
Society version of the Unified Parkinson's Disease Rating Scale [MDS-UPDRS] Part III)

- Agrees to use a medically acceptable method of contraception throughout the study and
for 6 weeks after completing the study. Medically acceptable methods of contraception
that may be used by the subject and/or partner include but are not limited to:
abstinence, oral contraception, NuvaRing or transdermal systems, diaphragm with
vaginal spermicide, intrauterine device, condom and partner using vaginal spermicide,
surgical sterilization (6 months), progestin implant or injection, or postmenopausal
female (no menstrual period for ˃ 2 years) or vasectomy (˃ 6 months).

- Montreal Cognitive Assessment (MoCA) score ≥ 24 at Screening Visit in "On" state.

- Able to differentiate "On" state from "Off" state as determined by at least 75%
concordance with a trained rater in "On/Off" ratings for 8 ratings over a 4-hour
training period. The concordance must include at least 1 "On" and 1 "Off" rating and
must be achieved within two 4-hour training sessions.

- Able and willing to comply with the protocol, including completion of diaries and
availability for all study visits.

- Responsive to CD-LD therapy and currently being treated on a stable regimen with CD-LD
for at least 4 weeks prior to Visit 1.

- At Screening, the subject has predictable "Off" periods.

Exclusion Criteria:

- Received any investigational medications within 30 days or 5 times the half-life,
whichever is longer, prior to Visit 1.

- Female subjects who are currently breastfeeding or lactating.

- Had prior neurosurgical treatment for PD or if such procedure is planned or
anticipated during the study period.

- Allergic to any excipient in the study drugs.

- History of medical conditions or of a prior surgical procedure that would interfere
with LD absorption, such as gastrectomy, proximal small-bowel resection, or bariatric
surgery.

- History of upper gastrointestinal hemorrhage in patients with peptic ulcer disease
within the past 5 years.

- History of glaucoma with intraocular pressures that are elevated despite appropriate
medical management.

- History of seizure or epilepsy and experienced at least 1 seizure during the past 12
months or has not been compliant with medically recommended therapy or visits.

- History of myocardial infarction with residual atrial, nodal, or ventricular
arrhythmias that are not controlled with medical and/or surgical interventions. A
recent (≤ 12 months) history of myocardial infarction with secondary arrhythmias is
exclusionary regardless of the therapeutic control.

- History of neuroleptic malignant syndrome or of nontraumatic rhabdomyolysis.

- Liver enzyme values ≥ 2.5 times the upper limit of normal; or history of severe
hepatic impairment.

- Serum creatinine level ≥ 1.75 times the upper limit of normal; or requires dialysis at
the time of Screening.

- Subject with a history of malignant melanoma or with a suspicious undiagnosed skin
lesion which in the opinion of the investigator could be melanoma.

- History of drug or alcohol abuse within the 12 months prior to Screening.

- Received within 4 weeks of Screening or planning to take during participation in the
clinical study:

- Any doses of a CR CD-LD apart from a single daily bedtime dose, any doses of
Rytary, additional CD (eg, Lodosyn) or benserazide (eg, Serazide), or
catechol-O-methyl transferase inhibitors (entacapone or tolcapone) or medications
containing these inhibitors (Stalevo),

- Nonselective monoamine oxidase inhibitors (MAOI), apomorphine, or
antidopaminergic agents, including antiemetics.

- Employees or family members of the investigator, study site, or sponsor.

- Subjects who have previously participated in an IPX203 study.

- Subjects who, in the opinion of the clinical investigator, should not participate in
the study.

- Based on clinical assessment, subject does not adequately comprehend the terminology
needed to complete the PD diary.