 The IRLSSG has developed and validated a 10-item scale for assessing the severity of RLS. The IRLS Rating scale will be assessed at the screening visit, the placebo initiation visit, the baseline visit and end of study visit and at the ET visit for subjects who withdraw prematurely. The investigator-rated CGI-I will be recorded at Baseline end of placebo administration and at the end of the Treatment Period and at the ET visit, if applicable. 