Safety and Preliminary Effectiveness of AV650 in Patients With Spasticity Associated With Multiple Sclerosis

Inclusion Criteria: * Male or female subjects between 18 and 70 years of age (inclusive) * Signed and dated informed consent * Definite MS as per Poser or MacDonald Criteria (either relapsing remitting or secondary progressive course) * Expanded Disability Status Score (EDSS) from 3.0 to 6.5 (inclusive) at Screening * Stable MS for at least 30 days before screening * Female of child bearing potential and male subjects whose partner is of child bearing potential who are willing to ensure that they or their partner use effective double-barrier contraception during the study and for 90 days thereafter * If female, be neither pregnant nor nursing (Confirmation that the subject is not pregnant must be established by a negative serum hCG pregnancy test at baseline.) * Significant spasticity in at least two muscle groups defined as a score of 2 or more on the Ashworth scale for each muscle group * If a subject is on anti-spastic treatments, the dosage, frequency, and route of administration must be stable for at least 30 days before Screening * If a subject is on MS treatments, the dosage, frequency, and route of administration must be stable for at least 30 days before Screening Exclusion Criteria: * Subjects who have participated in another research study within 90 days of Screening * Significant changes in anti-spasticity medications (dosage, frequency, or route of administration) within 30 days of Screening * Known hypersensitivity to tolperisone HCl, its components, or other lidocaine/lidocaine-like products * Use of tolperisone HCl within 30 days of screening * Significant changes in MS treatments (dosage, frequency, or route of administration) within 30 days of Screening * Spasticity due to neurological disorders other than MS * Any psychiatric disorder or cognitive impairment that precludes fully informed consent or safe participation in the study * Subjects who have suffered an acute relapse of MS or who continue to suffer from an acute relapse of MS within 90 days of Baseline * History of alcohol or substance abuse within one year of Screening * Concurrent clinically significant immunologic, pulmonary, renal, hepatic, or endocrine disease and/or other unstable or major disease other than MS * Clinically significant cardiovascular disorders, such as ischemic heart disease, arrhythmias, poorly controlled hypertension, or acute myocardial infarction * QT prolongation greater than 480 msec or greater than 450 msec if accompanied by a partial bundle branch block, or other ECG abnormality in the judgment of the Investigator * Diastolic blood pressure \<50mmHg or \>105mmHg; heart rate \<50 beats per minute (bpm) or \>110bpm, after 3 minutes in a sitting position; heart rate by ECG \<50bpm or \>110bpm * History of epilepsy (except childhood febrile seizures) * Current malignancy or history of malignancy that has not been in remission for more than five years, except basal cell skin carcinoma and cervical cancer (with treatment) * Female subject who is pregnant, nursing, or planning pregnancy during the course of the study * Scheduled elective surgery or other procedures requiring general anesthesia during the study * Subject who is terminally ill in the judgment of the Investigator * Subject who is inappropriate for placebo medication in the judgment of the Investigator * Systemic corticosteroid therapy within 28 days of randomization, with the exception of inhaled medications for asthma * Exacerbation of MS within 30 days of Baseline * Regular levo-dopa therapy within 7 days of randomization * Subjects taking antiarrhythmic medications * Donation of blood during the study