A Double-Blind, Randomized, Placebo-Controlled, Two-Dose Comparative Study of Botulinum Toxin Type A for Treating Glabellar Lines in Japanese Subjects

BACKGROUND: Systematic, well-controlled clinical trials of botulinum toxin type A (BoNTA) in diverse patient populations are needed. The aim of this study was to characterize the safety and efficacy of 10-U and 20-U BoNTA doses versus placebo for treating glabellar lines in Japanese subjects. METHODS: A 16-week, multicenter, double-blind, randomized, placebo-controlled trial comparing 10 or 20 U of BoNTA versus placebo in 142 Japanese subjects with glabellar lines of at least moderate severity at maximal contraction. The primary efficacy endpoint was physician-rated line severity at maximal contraction 4 weeks after treatment. Secondary efficacy endpoints included physician/subject ratings and estimates of the effect's duration. RESULTS: Response rates by physician-rated line severity at maximal contraction (week 4) were 86.4% (10 U), 88.6% (20 U), and 0% (placebo, p < 0.001). Line severity at maximal contraction in each BoNTA group (p < 0.001) improved significantly from baseline at each visit. BoNTA and placebo differed significantly on all other efficacy measures. Mean duration of effect was 9.4 weeks in the 20-U group and 7.9 weeks in the 10-U BoNTA group. No serious adverse events occurred. CONCLUSION: Doses of BoNTA of 10 and 20 U are effective and safe for treating glabellar lines in Japanese subjects, and the 20-U dose provides greater efficacy and longer duration of effect.