Comparing the clinical attributes of abobotulinumtoxinA and onabotulinumtoxinA utilizing a novel contralateral Frontalis model and the Frontalis Activity Measurement Standard.

Studies on the pharmacodynamics of abobotulinumtoxinA (ABO) and onabotulinumtoxinA (ONA) have produced inconsistent results. This may be due to the lack of objective measurement methods.To assess and compare pharmacodynamic attributes, including onset of action, spread and efficacy of ABO and ONA using a novel Frontalis Activity Measurement Standard (FMS) and 4-point Frontalis Rating Scale (FRS).Twenty subjects with severe frontalis lines at maximum elevation received equal volumes of ABO or ONA using a dose ratio of 2.5:1 in five injection points on contralateral sides of the frontalis (statistical n=40). Subjects were evaluated using the FMS and FRS for 30 days using pre-defined endpoints for onset and effectiveness. Other assessments included areas of effectiveness and injection pain.For ABO vs. ONA, the FMS revealed a median Initial Onset of 12 vs. 48 hours (P is less than 0.001), Full Onset of 24 vs. 72 hours (P is less than 0.001) and Complete Onset of three vs. five days (P=0.01). The FRS indicated an Initial Onset for ABO and ONA of 18 hours vs. two days (P=0.002), Full Onset of two vs. three days (P=0.001) and Complete Onset of four days vs. eight days (P=0.01). The FMS showed 90 percent of ABO treatment achieved Complete Efficacy vs. 75 percent for ONO, while 90 percent of ABO treatments reached Complete Efficacy using the FRS vs. 65 percent for ONO. No differences in area of effectiveness or spread were observed. Most subjects (80%) reported ABO injections were less painful than ONA injections (P< 0.05).The FMS appears to be a sensitive, objective tool for measuring ABO and ONA pharmacodynamics. Using a dose ratio of 2.5:1, ABO displayed significantly earlier onset of effect and less injection pain than ONA but similar areas of effectiveness.