XenoPort and GSK report positive results of Phase III RLS trial

XP13512 demonstrated statistically significant improvements compared to placebo on both of the co-primary endpoints of the trial and was generally well-tolerated. Results from the pre-specified analysis indicate that treatment with 1200mg of XP13512 was associated with statistically significant improvements in the co-primary endpoints compared to placebo. Improvements in the IRLS scale score were significantly greater for 1200mg XP13512 than for placebo (unadjusted mean values: -13.0 for 1200mg XP13512; -9.8 for placebo; p=0.0015). At the end of treatment, significantly more patients treated with 1200mg of XP13512 were reported as ‘much improved’ or ‘very much improved’ on the CGI-I scale compared to those treated with placebo (78% for 1200mg XP13512; 45% for placebo; p< 0.0001). Treatment with 600mg of XP13512 was also associated with statistically significant improvements in the IRLS and CGI-I endpoints compared to placebo. The unadjusted mean reduction in the IRLS scale score was -13.8 for 600mg XP13512 patients (p<0.0001 compared to placebo). At the end of treatment, 73% of patients treated with 600mg of XP13512 were reported as 'much improved' or 'very much improved' on the CGI-I scale (p<0.0001 compared to placebo). Atul Pande, senior vice president, GlaxoSmithKline Neurosciences Medicines Development Center, said: "This novel compound is the first non-dopaminergic agent to demonstrate efficacy in controlled clinical trials for the treatment of primary RLS and may offer patients a new treatment option. With the completion of this third Phase III clinical trial, we look forward to filing the NDA for primary RLS in the third quarter of 2008."