Background: IncobotulinumtoxinA and onabotulinumtoxinA are indicated for the temporary improvement in the appearance of glabellar frown lines (GFL). This is the first randomized direct comparator study to date, at the Food and Drug Administration-recommended dose of 20 units (U), for the treatment of GFL.
Objective: To investigate the dose equivalence of incobotulinumtoxinA (20 U) and onabotulinumtoxinA (20 U) for the treatment of moderate-to-severe GFL.
Materials and methods: Prospective, randomized (1:1), double-blinded, parallel-group study in 250 females (18-50 years), employing a single treatment with incobotulinumtoxinA or onabotulinumtoxinA, followed by a 4-month observational period.
Results: At the primary efficacy endpoint (1 month after treatment), incobotulinumtoxinA was equivalent to onabotulinumtoxinA in the treatment of GFL at the 20 U dose within the prespecified ± 15% margin of equivalence. Efficacy remained similar between treatment groups through 4 months after treatment as assessed by the independent masked panel and the masked treating physicians. Patient satisfaction ratings were similar between groups and favorable (>90%) throughout. Both treatments were well tolerated.
Conclusion: Equivalence was demonstrated at the primary endpoint between incobotulinumtoxinA and onabotulinumtoxinA in the treatment of GFL at the 20 U dose at 1 month. Similar efficacy and tolerability profiles were observed through 4 months after treatment.