[A double-blind comparative study to evaluate the efficacy and safety of NerBloc® (rimabotulinumtoxinB) administered in a single dose to patients with cervical dystonia].

We conducted a single-dose, placebo-controlled, double-blind, dose-response study of NerBloc®(rimabotulinumtoxinB) in patients with cervical dystonia (placebo, 2,500 U, 5,000 U, 10,000 U). The primary endpoint, the change in Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS)-total score at 4 weeks post dose from baseline, showed a significant improvement in all treatment groups (2,500 U, 5,000 U, 10,000 U) compared with the placebo group. As for the secondary endpoints, the change of TWSTRS subscales, severity, disability and pain scores, at 4 weeks post dose in 10,000 U group, showed a significant improvement compared with the placebo group, however, no significant differences were observed between 2,500 U or 5,000 U and placebo group. The subject's and physician's global assessments (visual analog scale; VAS) at 4 weeks post dose also showed significant improvement in all treatment groups relative to the placebo group, whereas subject's pain assessment (VAS) at 4 weeks post dose did not show significant improvement in any of treatment groups. The incidence rate of adverse events was not substantially different between the placebo group and 2,500 or 5,000 U group, but significantly higher in 10,000 U group than in the placebo group. Adverse events frequently observed in active drug groups included dry mouth/thirst and dysphagia, all of which were mild in severity. There were no adverse events that led to death, serious disorders or study discontinuations. The incidence rate of abnormal laboratory values did not show significant difference in any of parameters between the placebo group and any of treatment groups. NerBloc® possessing muscle relaxing effect is expected to be a potential treatment to improve symptoms of cervical dystonia. Clinically recommended dose will range from 2,500 U to 10,000 U. In this study, 10,000 U group was the most effective and the effect lasted the longest. The efficacy and safety profile of NerBloc ® in this study was similar to that in AN072-009 study conducted in the US.