Clinical protocol OS440-3003 is a multicenter, open-label, non-randomized, uncontrolled, dose escalation study to evaluate the safety and tolerability of Arbaclofen Extended Release Tablets (AERT) over 1 year in MS subjects with spasticity. All subjects in this study will receive arbaclofen in the extended release tablet formulation.~All subjects will begin treatment with arbaclofen at 20 milligrams (mg) per day (2 X 10 mg) for two weeks, then increase to 30 mg per day (2 X 15 mg) for two weeks, and then increase to 40 mg per day (2 X 20 mg) based on the Dose Escalation Criteria. Once the subject reaches the Maintenance Dose, they will remain on that dose for approximately 1 year. The Maintenance Dose is the highest tolerated dose, not to exceed 40 mg per day.~In this study, the Up Titration Period begins with Visit 2 and ends when the Maintenance Dose is determined. The Maintenance Period is the time from establishment of the Maintenance Dose until the down-titration visit. For subjects that complete the study, the Maintenance Period is for approximately 1 year in duration. The Down Titration Period will be 2 weeks for subjects on the maintenance dose of 40 mg per day and 1 week for subjects on the maintenance dose of 30 mg per day. There is no down titration phase for subjects on a 20 mg per day maintenance dose.~Subjects for whom the Maintenance Dose is 20 mg per day (i.e., subjects who did not tolerate the 30 mg/ day dose) will begin the 1 year Maintenance Period at Visit 4 and complete the study at Visit 8. Subjects for whom the Maintenance Dose is either 30 mg or 40 mg per day will begin the Maintenance Period at Visit 5 and complete the maintenance portion of the study at Visit 9.~The next portion of the study is down titration. The subjects on the 20 mg per day Maintenance Dose will not have a down-titration. For subjects on the 30 mg per day Maintenance Dose, down-titration will begin at Visit 9 and continue for 1 week. These subjects will return for Visit 10 after the 1 week down-titration. For subjects on the 40 mg per day Maintenance Dose, down titration will begin at Visit 9 and continue for 2 weeks. These subjects will return for Visit 10 after the 2 week down-titration.~Study visits will occur every two weeks until the Maintenance Dose is reached and then study visits will occur every three months with telephone follow-up calls monthly in between visits
Clinical protocol OS440-3003 is a multicenter, open-label, non-randomized, uncontrolled, dose escalation study to evaluate the safety and tolerability of Arbaclofen Extended Release Tablets over 1 year in Multiple Sclerosis (MS) subjects with spasticity. All subjects in this study will receive arbaclofen in the extended release tablet formulation.