This is a multicenter, randomized, double-blind, placebo-controlled, parallel-group study to evaluate the safety and efficacy of oral arbaclofen ER tablets (80 mg/day) in MS patients with spasticity. Arbaclofen ER will be compared with placebo. The treatment groups will be randomized in a 1:1 ratio. There will be a 49-day dose escalation period, followed by a 84-day maintenance treatment period, followed by a 21-day taper period.
