Botulinum toxin type B: An effective treatment for alleviating pain associated with cervical dystonia.

Neck pain is reported in 75% is strongly associated with greater disability and decreased quality of life. Botulinum toxin type B (BoNT-B; Myobloc™) is a new botulinum toxin that has been proven safe and effective in reducing the pain, severity, and disability of patients with cervical dystonia. We analyzed a subset of efficacy data from two randomized, double blind, placebo-controlled clinical trials. The first study consisted of three treatment groups in patients who were responders to the type A toxin, including placebo (n=36), 5000 units (U) (n=36), 10,000 U (n=37). The second study consisted of placebo (n=38) and 10,000-U treatment groups (n=39) in patients not responding to the type A toxin. For this analysis, the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS)-subscale scores for pain and three visual analog scales (Patient Analog Pain, Patient Global, and Principal Investigator Global Assessments) were evaluated. A dose-response effect was observed in the reduction of pain based on the TWSTRS-subscale scores. In both studies, mean improvements from baseline to week 4 for all patients were significant compared with placebo (P<0.005). BoNT-B also significantly improved mean values for all VAS assessments. Our analysis confirms that BoNT-B significantly reduces the pain associated with cervical dystonia and improves patients' overall condition. This clinical benefit suggests that BoNT-B may be useful in other pain syndromes involving involuntary muscle spasms or contractions.