GSK and Xenoport report positive RLS results

GlaxoSmithKline (GSK) and Xenoport have announced positive top-line results for a phase III clinical trial of XP13512 (GSK1838262) for the treatment of moderate-to-severe restless leg syndrome.

The candidate demonstrated significant improvements compared to placebo in both of the co-primary endpoints and was well-tolerated.

Over 300 patients with primary RLS were enrolled and administered with 1200 mg or 600 mg of XP13512 or placebo once per day.

The co-primary endpoints of the trial were the change from baseline for the International RLS rating scale score and the percentage of patients showing improvement on the Investigator Clinical Global Impression of Improvement (CGI-I) scale at end of treatment.

While improvements in the IRLS scale score were significantly greater for the 1200 mg regimen compared to placebo, treatment with 600 mg of XP13512 was also associated with statistically significant IRLS and CGI-I endpoints.

“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,” said Atul Pande, senior vice-president of GSK’s Neurosciences Medicine Development Centre.

This week has seen GSK publicly reject the findings of a new study which suggests antidepressants have limited clinical benefit to most patients.