Objective: To measure and compare the duration of action of abobotulinumtoxinA and onabotulinumtoxinA.
Design: Randomized, double-blind, contralateral (split-face) study.
Setting: Two United States clinical sites.
Participants: Twenty subjects with severe frontalis lines at maximum elevation.
Measurements: Subjects randomly received equal volumes of abobotulinumtoxinA or onabotulinumtoxinA (0.2mL) in five injection points on contralateral sides of the frontalis (N=40) using a dose ratio of 2.5:1.0 (total 25U abobotulinumtoxinA:10U onabotulinumtoxinA), respectively. Subjects were evaluated using a 4-point Frontalis Rating Scale and a new objective Frontalis Activity Measurement Standard for 210 days using predefined endpoints for efficacy.
Results: Using the Frontalis Activity Measurement Standard, the median duration of "complete efficacy" was 72 days for abobotulinumtoxinA and 56 days for onabotulinumtoxinA (p=0.01), "full efficacy" was 103 days for abobotulinumtoxinA and 87 days for onabotulinumtoxinA (p<0.003), and "partial efficacy" was 105 days for abobotulinumtoxinA and 99 days for onabotulinumtoxinA (p=0.006). Using the Frontalis Rating Scale, the median duration of "complete efficacy" was 63 days for abobotulinumtoxinA and 44 days for onabotulinumtoxinA (p=0.006), "full efficacy" was 119 days for abobotulinumtoxinA and 77 days for onabotulinumtoxinA (p=0.005), and "partial efficacy" was 160 days for abobotulinumtoxinA and 145 days for onabotulinumtoxinA (p=NS). Adverse events included local bruising and occasional headache, but no significant inter-group differences.
Conclusion: The contralateral Frontalis Activity Measurement Standard is well-suited for assessing the pharmacodynamic and clinical attributes of botulinum toxin type A and can be used to measure differences in the clinical properties of abobotulinumtoxinA and onabotulinumtoxinA. Using a dose ratio of 2.5:1.0, abobotulinumtoxinA displayed significantly longer duration of action than onabotulinumtoxinA.