OnabotulinumtoxinA displayed larger fields of effect than abobotulinumtoxinA in forehead injections

Diffusion of onabotulinumtoxinA injected into patients’ foreheads had greater fields of anhidrotic effect than doses of a similar size of abobotulinumtoxinA in a recent study.

Researchers in Brazil conducted a prospective randomized, double blind study of 18 women injected with 2 U per 0.02 mL reconstituted onabotulinumtoxinA and 2 U per 0.02 mL reconstituted abobotulinumtoxinA on each side of their foreheads. Primary outcomes were the horizontal and vertical diameters and fields of anhidrotic effect (FAE), plus 4-point validated Wrinkle Severity Scale (WSS) scores at 28 days.

At follow-up, the FAE and horizontal and vertical diameters were larger on the sides of patients’ foreheads where onabotulinumtoxinA was injected compared with the abobotulinumtoxinA-injected side (P<.001).

At baseline and at 28 days, WSS scores indicated no significant differences between either injection when assessing muscle contraction or at rest, although patients had lower WSS scores after treatments. Researchers also found evoked compound muscle action potential (ECMAP) values similar between products, with each producing significant reductions in ECMAP from baseline to follow-up (P<.001 for both).

“OnabotulinumtoxinA has significantly larger FAE than abobotulinumtoxinA when isovolumetric injections of the same labeled unit doses of the products were injected,” the researchers concluded, “supporting the theory that the FAE is mainly related to the dose used in clinical practice and equivalent ratios in clinical trials.

“Both products had similar results for cosmetic use and muscular effect after 28 days,” the study authors wrote.

Disclosure: Researcher Doris Hexsel, MD, received research funding from L’Oréal, Cynosure, Syneron, Ipsen, Allergan, Galderma and Medicis; has served as a consultant for Ipsen and Galderma; and has been a member of the speaker bureaus for Ipsen and Galderma.