A Placebo-Controlled Study for SPM 962 in Restless Legs Syndrome (RLS) Patients

Inclusion Criteria: 1. Subject is 20 and more and less than 80 years of age and is able to think about her/his participation at the time of informed consent. 2. Subject meets the diagnosis of idiopathic RLS based on the 4 cardinal clinical features according to the IRLSSG/NIH. 3. The following subject will be included in the study * Subject is not currently receiving treatment for RLS. * Subject has previously received treatment of either L-dopa or dopamine agonists and efficacy was observed in either of drugs. 4. At baseline, subject has a score of ≧ 15 on the IRLS sum score and RLS symptoms occur twice and more a week (≧score 2 in IRLS Question 7) 5. Subject has a score of ≧ 4 on the CGI Severity score at baseline Exclusion Criteria: 1. Subject has secondary RLS in association with renal impairment such as uremia，iron deficiency anemia, and drug associated symptoms. 2. Subject has, is suspected of having or has a history of sleep disorders such as sleep apnea syndrome, narcolepsy, sleep attacks/sudden onset of sleep. 3. Subject has additional clinically relevant concomitant diseases or symptoms such as polyneuropathy (including diabetic neuropathy), akathisia，claudication varicoses，muscle fasciculation，painful legs moving toes and radiculopathy. 4. Subject has other central nervous diseases like Parkinson's disease, dimentia, progressive supranuclear paresis, multisystem atrophy, Huntington's Chorea, amyotrophic lateral sclerosis, or Alzheimer's disease. 5. At screening or baseline, subject has psychiatric condition like confusion, hallucination, delusion, excitation, deliria, abnormal behaviour. 6. Subject has orthostatic hypotension or systolic BP marks ≦ 100 mm Hg and with a decrease of BP from supine to standing position of ≧ 30 mm Hg. 7. Subject has a history of epilepsy, convulsion etc. 8. Subject has serious cardiac dysfunction and/or arrhythmias (e.g., congestive heart failure Class III or IV by NYHA, myocardial infarction, angina pectoris, conduction system dysregulations, second or third degree AV block, complete left bundle branch block, sick-sinus-syndrome, ventricular fibrillation within twelve months prior to enrollment). 9. Subject has arrhythmia and receiving Class Ia antiarrhythmic drugs(e.g., quinidine, procainamide), Class III antiarrhythmic drugs (e.g., amiodarone, sotalol) 10. At screening and baseline, subject develops serious ECG abnormality. Subjects has QTc-interval \>450 msec twice at screening. Subject has a the average QTc-interval from two ECGs \>450 msec in males and \>470 msec in females at baseline. 11. Subject has long QT syndrome congenital. 12. Subject has a serum potassium level \< 3.5 mEq/L at screening. 13. Subject has a total bilirubin ≧3.0 mg/dL or AST(GOT) and/or ALT(GPT) greater than 2.5 times the upper limit of the reference range (or ≧100 IU/L) at screening. 14. Subject has BUN ≧ 30 mg/dL or serum creatinine ≧2.0 mg/dl at screening. 15. Subject has a history of allergic reaction to topical agents such as transdermal patch. 16. Subject is pregnant or nursing or woman who plans pregnancy during the trial. 17. Subject pursues shift work or is subject to other continuous non-disease-related life conditions which do not allow regular sleep at night. 18. Subject has autoimmune disease, chronic active hepatitis or immune deficiency disorder. 19. Subject has a malignant neoplastic disease requiring therapy within twelve months prior to screening. 19\. Subject received an investigational drug from other clinical trial within the last 12 months prior to baseline. 20\. Subject is judged to be inappropriate for this trial by investigator on the other than above.