Repeated OnabotulinumtoxinA Treatment of Glabellar Lines at Rest Over Three Treatment Cycles

BACKGROUND OnabotulinumtoxinA has demonstrated the ability to eliminate mild glabellar lines at rest; however, less is known regarding the effect of repeat treatment on more severe lines at rest. OBJECTIVE To assess the effect of repeated onabotulinumtoxinA treatment for reduction of glabellar lines at rest. METHODS Subjects 18 to 75 years old with at least mild glabellar lines at rest, as assessed by the validated Facial Wrinkle Scale (FWS) with photonumeric guide (score ≥ 1), received 3 treatments of 20 U onabotulinumtoxinA 4 months apart (N = 225). "Response" was defined as elimination of glabellar lines at rest (FWS score = 0) at any time point (Days 7, 30, 60, 90, and 120). Effect of treatment cycle on response was analyzed using repeated measures logistic regressions (p < .05). RESULTS Most subjects were female (85%) and white (88%) (age range: 35-54 years). The likelihood of significant response was as follows: for all subjects combined (odds ratio [OR]: 1.31), for subjects with mild resting lines at baseline (OR: 1.49), and for older women (≥55 years) with mild resting lines at baseline (OR: 2.22). Of all subjects, 76% responded after 1 treatment, and 45% responded in all 3 cycles. CONCLUSION Subjects repeatedly treated with onabotulinumtoxinA showed progressive improvement in glabellar lines at rest.