Efficacy Study of Arbaclofen to Treat Spasticity in Multiple Sclerosis

This is a multicenter, randomized (1:1:1), double-blind, active and placebo controlled, parallel group study to evaluate safety, tolerability and efficacy of oral arbaclofen in MS patients with spasticity. Eligible subjects will be removed from anti-spasticity medications for at least one week and then begin study drug treatment with daily doses increasing up to the target dose which will then be maintained for at least 12 weeks. A down-titration will then occur over two weeks with the final study visit occurring at 19 weeks from start of achieving the target dose or 22 weeks from the Study Visit 1.