OnabotulinumtoxinA: A Meta-Analysis of Duration of Effect in the Treatment of Glabellar Lines

BACKGROUND Duration of effect of aesthetic treatments with botulinum toxin potentially influences subject satisfaction, treatment frequency, and annual costs, but quantitative outcomes for measuring duration of effect and correlations with subject satisfaction have yet to be fully elucidated. METHODS AND MATERIALS Phase III clinical trials with similar designs were identified and their data pooled to ascertain duration of clinical effect of onabotulinumtoxinA in glabellar muscles. Duration was calculated using the KaplanMeier method for investigator-rated Facial Wrinkle scale (FWS) scores and subject global assessment (SGA) of glabellar lines. Responders were determined according to FWS score at maximum contraction and at repose 30 days after injection. RESULTS Data from four trials with 621 onabotulinumtoxinA-treated (20 U) subjects were analyzed, 523 of these (84.2%) were identified as day-30 responders on the FWS at maximum contraction. Pooled median duration of effect for day-30 responders was 120 days for FWS at maximum contraction and 131 days for FWS at repose. Higher day 30 SGA scores were correlated with a greater duration of effect on dynamic, but not static lines. CONCLUSION Treatment of glabellar lines with 20 U of onabotulinumtoxinA resulted in sustained clinical benefit for 4 months in more than 50% of responders; subject satisfaction increased with duration of effect.