Efficacy and safety of botulinum type A toxin in adductor spasticity due to multiple sclerosis

Objective: To assess the efficacy of Clostridium botulinum type A toxin-hemagglutinin complex [BoNT-A, Dysport (R)] in the treatment of adults with adductor muscle spasticity due to definite or probable multiple sclerosis [MS]. Methods: In this 12-week multinational, randomized, double-blind, placebo-controlled trial, patients received a single treatment of either BoNT-A 1,000-1,500 Ipsen units or placebo injected into the adductor muscles of each leg [500-750 Ipsen units per leg]. The primary outcome measure was it novel, patient-selected, functional outcome measure at week 4. Results: Fifty-five subjects were treated with BoNT-A, and 51 received the placebo. Treatment benefit in favor of BoNT-A, which tended toward significance, was seen for most endpoints but not the subjective patient-selected key outcome measure. As with a previous dose-ranging study of BoNT-A, pain was significantly reduced in both legs [P<0.05 at weeks 8 and 12]. Lack of significance for the other endpoints was probably due to the low number of patients who received the full 1,500 Ipsen unit dose of BoNT-A, which has previously been shown to be effective. The majority of adverse events were mild-to-moderate in severity and resolved within it few days. Conclusion: The BoNT-A was shown to provide effective pain relief in patients with severe adductor spasticity due to MS, and the trend toward treatment benefit for the primary endpoint is in line with previously published literature.