Comparison of the spread of three botulinum toxin type A preparations.

Botulinum toxins are frequently used in esthetics to improve the appearance of facial wrinkles. In this setting, precise localization of the neurotoxin is required to produce the desired clinical effects. Unwanted effects can occur if the neurotoxin diffuses into untargeted muscle. Therefore, a neurotoxin with low and predictable spread would be preferable for esthetic applications. The aim of this study was to investigate the spread of three approved botulinum toxin type A preparations, with and without complexing proteins, by measuring and comparing the size of the anhidrotic halos they produced following injection of equivalent doses in an identical volume into the forehead of patients. The results showed that incobotulinumtoxinA and onabotulinumtoxinA displayed comparable spread at 6 weeks (maximal area of anhidrosis within 6 weeks) and area under the effect curve (AUEC) over 6 months. However, abobotulinumtoxinA, when assuming a 1:2.5 injection volume ratio, produced a statistically significantly greater maximal area of anhidrosis within 6 weeks and AUEC over 6 months compared with incobotulinumtoxinA. All preparations were well tolerated. The results of this study demonstrate that incobotulinumtoxinA and onabotulinumtoxinA have comparable spread, while abobotulinumtoxinA has significantly greater spread than incobotulinumtoxinA.