A Study to Investigate Arbaclofen ER Tablets for the Treatment of Spasticity in Patients With Multiple Sclerosis

Inclusion Criteria: * Subjects 18 to 65 years of age, inclusive * An established diagnosis per McDonald Criteria (Polman et al 2011) of MS (either RR or SP course) that manifests a documented history of spasticity for at least 6 months prior to screening * Spasticity due to MS as shown by a TNmAS-MAL score ≥ 2 * Expanded Disability Status Scale (EDSS) score greater than or equal to (≥) 3.0 and less than or equal to (≤) 7.0 * Absence of infections, peripheral vascular disease, painful contractures, advanced arthritis, or other conditions that hinder evaluation of joint movement * Use of a medically highly effective form of birth control (see Section 7.8) during the study and for 3 months thereafter for women of child-bearing potential (including female subjects and female partners of non-sterile male subjects) * Willing to sign the informed consent form (ICF) Exclusion Criteria: * Any concomitant disease or disorder that has symptoms of spasticity or that may influence the subject's level of spasticity * In the opinion of the investigator, the patient is unable to rate their level of spasticity or distinguish it from other MS symptoms * Concomitant use of medications that would potentially interfere with the actions of the study medication or outcome variables * Pregnancy, lactation, or planned pregnancy during the course of the study and for 3 months after the final study visit * Current significant cognitive deficit, severe or untreated anxiety, severe or untreated depres…