A Study of MK0657 in Parkinson’s Disease Patients (0657-006)


In this clinical trial, the safety of MK0657 when given with levodopa will be assessed in patients with Parkinson's Disease. This study will also measure the effectiveness of MK0657, when given in combination with levodopa, to improve motor symptoms and ameliorate dyskinesias (uncontrolled movements of a part of the body) as compared to placebo.

Full Title of Study: “A Randomized, Double-Blind, Placebo-Controlled, 2-Period Crossover Study to Evaluate Effectiveness of Single-Dose MK0657 in Combination With Levodopa on Motor Symptoms and Dyskinesias in Patients With Parkinson’s Disease”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Crossover Assignment
    • Primary Purpose: Treatment
    • Masking: Double (Participant, Investigator)
  • Study Primary Completion Date: February 2008


  • Drug: MK0657
    • 7mg MK0657 capsules
  • Drug: Comparator: Placebo (unspecified)
    • 7mg MK0657 Pbo capsules
  • Drug: Comparator: levodopa
    • levodopa >/=1.0 mg/kg/hr dose of levodopa. levodopa infusions will occur over a 2 hour period
  • Drug: Comparator: carbidopa
    • carbidopa 25mg administered 3 times: at 1 hour before levodopa infusion and at 1 and 3 hours after the start of levodopa infusion.

Arms, Groups and Cohorts

  • Other: 1
    • 7mg MK0657 capsules + >/=1.0 mg/kg/hr dose of levodopa.
  • Other: 2
    • 7mg MK0657 Pbo capsules + >/=1.0 mg/kg/hr dose of levodopa.

Clinical Trial Outcome Measures

Primary Measures

  • Efficacy will be assessed for up to 8 hours by the Unified Parkinson’s Disease Rating Scale-Motor Examination and a modified AIMS dyskinesia scale
    • Time Frame: 45 Days

Secondary Measures

  • Safety and Tolerability
    • Time Frame: 45 Days

Participating in This Clinical Trial

Inclusion Criteria

  • Parkinson's Disease patients between the ages of 40 and 80 inclusive – Patient is in general good health based on screening assessments – Patient is willing to discontinue anti-parkinson's medications at least 8 hours prior to dosing – Patient is levodopa responsive with levodopa-induced peak-dose dyskinesias – Patient taking selective serotonin inhibitors (SSRIs), sleep medications and neuroleptics, have been on a stable dose for at least 30 days and has not experienced any CNS-related side effects – Patient is not a heavy smoker or drinker Exclusion Criteria:

  • Patient has atypical Parkinson's syndrome due to drugs, identified metabolic and/or neurologic disorders, encephalitis, or other degenerative syndrome – Patient has known intolerance or hypersensitivity to levodopa or carbidopa – Patient has been on anticholinergics or memantine within 30 days prior to dosing – Patients have a history of the following: seizure disorder, stroke or head trauma, pronounced cognitive impairment, psychiatric disorder, cardiovascular disease, cancer, diabetes as defined by HbA1c of greater than 8% – Patient has a systolic BP or less than 80 mm Hg or greater than 150 mm Hg

Gender Eligibility: All

Minimum Age: 40 Years

Maximum Age: 80 Years

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • Merck Sharp & Dohme Corp.
  • Provider of Information About this Clinical Study
    • Sponsor
  • Overall Official(s)
    • Medical Monitor, Study Director, Merck Sharp & Dohme Corp.

Citations Reporting on Results

Addy C, Assaid C, Hreniuk D, Stroh M, Xu Y, Herring WJ, Ellenbogen A, Jinnah HA, Kirby L, Leibowitz MT, Stewart RM, Tarsy D, Tetrud J, Stoch SA, Gottesdiener K, Wagner J. Single-dose administration of MK-0657, an NR2B-selective NMDA antagonist, does not result in clinically meaningful improvement in motor function in patients with moderate Parkinson's disease. J Clin Pharmacol. 2009 Jul;49(7):856-64. doi: 10.1177/0091270009336735. Epub 2009 Jun 2.

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