A Pharmacodynamic Comparison Study of Different Botulinum Toxin Type A Preparations

BACKGROUND Because more botulinum toxin (BoNT) preparations have become available worldwide, there is a clinical need to compare the pharmacologic profiles of these products. OBJECTIVE We compared three different preparations: onabotulinumtoxinA (ona-BoNT/A), abobotulinumtoxinA (abo-BoNT/A), and Neuronox (neu-BoNT/A), in a mouse model using a digit abduction scoring (DAS) assay. METHODS The efficacy, duration of effect, and safety margin of each preparation was determined after delivering a single injection to the right gastrocnemius (0–240 U/kg body weight of neu-BoNT/A or ona-BoNT/A; 0–600 Speywood Units/kg body weight of abo-BoNT/A). RESULTS Neu-BoNT/A (intramuscular (IM) median effective dose (ED50) 11.2 ± 2.7 U/kg) and ona-BoNT/A (IM ED50 11.9 ± 2.4 U/kg) had similar effects in terms of muscle weakness at significantly lower doses than abo-BoNT/A (IM ED50 41.2 ± 2.4 U/kg; p < .001). The safety margin (ratio between IM ED50 and IM median lethal dose (LD50)) of neu-BoNT/A (10.7 ± 2.6 U/kg) was also similar to that of ona-BoNT/A (10.3 ± 1.3 U/kg) but significantly higher than that of abo-BoNT/A (5.9 ± 0.4 U/kg; p < .02). Neu-BoNT/A and ona-BoNT/A also produced comparable patterns of DAS response and body weight recovery by day 29. CONCLUSION Neu-BoNT/A and ona-BoNT/A may be interchangeable based on a simple dose ratio.