Lateral canthal lines or crow's feet lines (CFL) may be treated with onabotulinumtoxinA. We identified several key concepts important to understanding the use of onabotulinumtoxinA for treatment of moderate-to-severe CFL. To contextualize and integrate data on the recommended dose and injection patterns of onabotulinumtoxinA for treatment of CFL, we summarized data from pivotal clinical studies in the development of onabotulinumtoxinA for treatment of CFL. Data from key studies of onabotulinumtoxinA for CFL are presented. The efficacy and safety of onabotulinumtoxinA treatment of moderate-to-severe CFL were evaluated in 2 randomized, controlled phase 3 studies comprising 1362 patients. The 24U total dose of onabotulinumtoxinA used in these studies was based on a phase 2 dose-ranging trial. Two injection patterns were available to investigators; each involved 3 injection sites per side in the lateral orbicularis oculi muscle. A cross-sectional analysis of photographs from the phase 3 trials provided detailed information on the frequency of 4 distinct CFL patterns. In the primary efficacy analysis for each phase 3 trial, CFL responder rates were significantly greater with onabotulinumtoxinA vs placebo at day 30 (P< .001). Eyelid edema (1%) was the only adverse event reported in ≥ 1% of patients receiving onabotulinumtoxinA, occurring more frequently with onabotulinumtoxinA than with placebo. The studies showed that onabotulinumtoxinA is effective and generally well-tolerated for CFL treatment. Additionally, 2 different injection patterns allow physicians to tailor treatment based on a patient's CFL pattern.
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