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Study of Istradefylline (KW-6002) for the Treatment of Restless Legs Syndrome

This study has been completed.
Information provided by:
Kyowa Hakko Kirin Pharma, Inc. Identifier:
First received: September 13, 2005
Last updated: June 22, 2010
Last verified: February 2007

The primary purpose of this study is to evaluate the efficacy, safety, and tolerability of 40 mg per day of istradefylline (KW6002) in patients with Restless Legs Syndrome.

Condition Intervention Phase
Sleep Disorder
Restless Legs Syndrome
Drug: Istradefylline (KW-6002)
Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Parallel Assignment
Masking: Double-Blind
Primary Purpose: Treatment
Official Title: A Phase 2, Double-blind, Placebo-controlled, Randomized, Parallel-Group, Multicenter Study to Evaluate the Efficacy and Safety of 40mg/Day KW-6002 (Istradefylline) in Subjects With Restless Legs Syndrome

Resource links provided by NLM:

Further study details as provided by Kyowa Hakko Kirin Pharma, Inc.:

Primary Outcome Measures:
  • Change from baseline in an RLS rating scale score at endpoint (6 weeks of treatment or early discontinuation).

Secondary Outcome Measures:
  • Change from baseline values in an RLS rating scale score, in the a sleepiness scale, in values for Clinical Global Impression, in quality of life, and in actigraphic measurements.
  • Safety

Estimated Enrollment: 160
Study Start Date: July 2005
Estimated Study Completion Date: September 2006
Detailed Description:

Restless Legs Syndrome (RLS) is a very common neurological disorder with a prevalence of approximately 10% in the adult population. It is characterized by an almost irresistible urge to move the legs, usually accompanied by feelings of intense discomfort. The feelings are usually present while at rest and are temporarily relieved by activity. Symptoms are worse in the evening and at night and lead to profound sleep disturbance and daytime fatigue.

Although a number of therapeutic approaches have been used to treat the symptoms of RLS, none have been universally adopted. While it has been shown that some dopaminergic anti-parkinsonian medications are effective in treating RLS, their use may be somewhat limited by side effects associated with long-term dopaminergic activation. Istradefylline may provide a nondopaminergic approach to the treatment of RLS.

This study will compare the efficacy of 40 mg per day of istradefylline in improving the symptoms of RLS with placebo.


Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No

Inclusion Criteria:

RLS that is mild to moderate in severity, non-nursing and non-pregnant if female, with an otherwise normal examination.

Exclusion Criteria:

Unable to stop other RLS medication, treatment with excluded medications, abnormal medical status.

  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT00199446

United States, New Jersey
Kyowa Pharmaceutical Inc.
Princeton, New Jersey, United States, 08540
Sponsors and Collaborators
Kyowa Hakko Kirin Pharma, Inc.
Study Director: James Williams, MD Kyowa Hakko Kirin Pharma, Inc.
  More Information

No publications provided Identifier: NCT00199446     History of Changes
Other Study ID Numbers: 6002-US-201
Study First Received: September 13, 2005
Last Updated: June 22, 2010
Health Authority: United States: Food and Drug Administration

Keywords provided by Kyowa Hakko Kirin Pharma, Inc.:
Sleep -Sleep Disorder
Sleep- Restless Legs Syndrome
Clinical Trial

Additional relevant MeSH terms:
Psychomotor Agitation
Restless Legs Syndrome
Sleep Disorders
Mental Disorders
Nervous System Diseases
Neurobehavioral Manifestations
Neurologic Manifestations
Pathologic Processes
Psychomotor Disorders
Signs and Symptoms
Sleep Disorders, Intrinsic
Adenosine A2 Receptor Antagonists
Molecular Mechanisms of Pharmacological Action
Neurotransmitter Agents
Pharmacologic Actions
Physiological Effects of Drugs
Purinergic Agents
Purinergic Antagonists
Purinergic P1 Receptor Antagonists processed this record on November 25, 2014