232) Botulinum Toxin Type B Decreases Pain in Patients with Cervical Dystonia

Neck pain occurs in a majority of patients with cervical dystonia. The cause of pain is unknown but may be attributable to the presence of spasms in dystonic or compensatory cervical muscles. Pain also occurs in other dystonic conditions. Because it acts to alleviate excessive muscle contraction, botulinum toxin may be a reasonable therapeutic treatment of painful dystonic conditions. In this analysis, the efficacy of the type B serotype (BoNT-B; Myobloc™) in reducing pain was evaluated using pain and quality of life data from two randomized, placebo-controlled clinical trials of patients with cervical dystonia (Brashear A et al. Neurology. 1999;53:1439–1446; Brin MF et al. Neurology. 1999;53:1431–1438). The first study consisted of three BoNT-B dose groups, including placebo (n = 36), 5000 units (U) (n = 36), 10,000 U (n = 37). The second study included placebo (n = 38) and 10,000-U dose groups (n = 39). Efficacy outcomes included the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS)-pain scores and three VAS (Patient Analog Pain, and Patient and Principal Investigator Global Assessments). Based on the TWSTRS-pain scores, BoNT-B produced a dose-dependent reduction in pain. In the first study, mean improvements from baseline to week 4 were 0.5, 3.6, and 4.2 for the placebo, 5000-U, and 10,000-U dose groups, respectively. In the second study, they were 0.1 and 3.6 for the placebo and 10,000-U dose groups, respectively. All differences were significant compared with placebo (P < 0.005). BoNT-B also significantly improved mean values for all VAS assessments. Patients who received BoNT-B generally felt better and had less pain compared with their pretreatment status. Based on this analysis, BoNT-B significantly reduces the pain associated with cervical dystonia and improves patients' overall quality of life, suggesting that BoNT-B may be useful in other painful dystonic conditions. The support of Elan Pharmaceuticals is gratefully acknowledged.