Extended Release Amantadine Safety and Efficacy Study in Levodopa-Induced Dyskinesia (EASED Study)

Inclusion Criteria:

- Signed a current IRB/IEC-approved informed consent form

- Parkinson's disease, per UK Parkinson's Disease Society (UKPDS) Brain Bank Clinical
Diagnostic Criteria

- On a stable regimen of antiparkinson's medications , including any levodopa
preparation administered not less than three times daily, and willing to continue the
same doses and regimens during study participation

- Experiencing troublesome dyskinesia following levodopa dosing (peak dose dyskinesia)

- Able to understand and complete a standardized PD home diary, following training

Exclusion Criteria:

- History of neurosurgical intervention related to Parkinson's disease (e.g. deep brain
stimulation)

- History of seizures or stroke/TIA within 2 years of screening

- History of cancer within 5 years of screening, except adequately treated
non-melanomatous skin cancers, localized bladder cancer, non-metastatic prostate
cancer or in situ cervical cancer

- Estimated GFR < 50 mL/min/1.73m2

- Presence of cognitive impairment, as evidenced by a Mini-Mental Status Examination
(MMSE) score of less than 24 during screening

- If female, is pregnant or lactating, or has a positive pregnancy test result pre-dose

- If a sexually active female, is not surgically sterile or at least 2 years
post-menopausal, or does not agree to utilize an effective method of contraception
from screening through at least 4 weeks after the completion of study treatment

- Treatment with an investigational drug or device within 30 days prior to screening

- Treatment with an investigational biologic within 6 months prior to screening