No abstract

Botulinum neurotoxin injections are a valuable treatment modality for many therapeutic indications and have revolutionized the field of aesthetic medicine so that they are the leading cosmetic procedure performed worldwide. Studies show that onabotulinumtoxinA, abobotulinumtoxinA, and incobotulinumtoxinA are comparable in terms of clinical efficacy. Differences between the products relate to the botulinum neurotoxin complexes, specific biological potency, and their immunogenicity. Protein complex size and molecular weight have no effect on biological activity, stability, distribution, or side effect profile. Complexing proteins and inactive toxin (toxoid) content increase the risk of neutralizing antibody formation, which can cause secondary treatment failure, particularly in chronic disorders that require frequent injections and long-term treatment. These attributes could lead to differences in therapeutic outcomes, and, given the widespread aesthetic use of these three neurotoxin products, physicians should be aware of how they differ to ensure their safe and effective use.

Background: Botulinum neurotoxin type A (BoNT/A) is the active substance in preparations used for the highly effective treatment of neurologic disorders such as cervical dystonia, blepharospasm, or spasticity, as well as other indications such as axillary and palmar hyperhidrosis, and urologic disorders.Objective: To determine the amount of BoNT/A protein present in pharmaceutical preparations of Botox®, Dysport®, and Xeomin®, which are identical with Vistabel®, Azzalure®, and Bocouture®, respectively.Methods: Rabbit and guinea pig antibodies raised against the 150kD BoNT/A neurotoxin purified from Clostridium botulinum type A, strain ATCC 3502 (‘Hall strain’), were used in a sensitive sandwich ELISA to determine the overall mean concentration of the 150kD neurotoxin present in four batches of Botox® (C2344C3, C2384C3, C2419, and C2385), two batches of Dysport® (678F and 689X) and three batches of Xeomin® (61111, 70604, and 81 208). The specific neurotoxin potency, defined as the potency or biologic activity (units) per mass of neurotoxin protein (ng), was calculated based on the overall mean concentration of BoNT/A neurotoxin.Results: Overall, the mean concentration of BoNT/A neurotoxin in Botox® was 0.73 ng per 100 unit vial (coefficient of variation [CV] = 3.5%), 3.24 ng per 500 unit vial of Dysport®, corresponding to 0.65 ng in 100 units (CV = 11.4%), and 0.44 ng per 100 unit vial of Xeomin® (CV = 1.9%). The specific potency of the 150kD BoNT/A neurotoxin was calculated as 137 units/ng for Botox®, 154 units/ng Dysport®, and 227 units/ng Xeomin®.Conclusions: The current study has shown that of the three products, Xeomin® contains the highest specific neurotoxin activity, followed by Dysport®, with Botox® having the lowest specific activity. This result suggests that Xeomin® contains only active neurotoxin in contrast with Botox®, which is likely to contain additional denatured/inactive neurotoxin.

Botulinum toxin type A is a high molecular weight protein complex containing active neurotoxin and complexing proteins, the latter of which, it is believed, protect the neurotoxin when in the gastrointestinal tract, and may facilitate its absorption. Comparisons of conventional botulinum toxin type A drugs that include complexing proteins with the complexing protein-free formulation of Xeomin® strongly suggest that complexing proteins do not affect diffusion of the active neurotoxin. Studies of Xeomin have also shown that complexing proteins do not enhance product stability in storage. However, complexing proteins may stimulate antibody development against botulinum toxin type A. Numerous observational studies have been published showing that some patients receiving conventional botulinum toxin may develop neutralizing antibodies, leading to antibody-induced therapy failure. Studies have shown that Xeomin is not associated with the development of neutralizing antibodies in animal models or in patients. In conclusion, complexing proteins do not contribute to the stability of botulinum toxin type A drugs and do not contribute to their therapeutic effects, but may be associated with a secondary nonresponse due to the development of neutralizing antibodies.

Background: Botulinum neurotoxin type A (BoNT/A) is the active substance in preparations used for the highly effective treatment of neurologic disorders such as cervical dystonia, blepharospasm, or spasticity, as well as other indications such as axillary and palmar hyperhidrosis, and urologic disorders. Objective: To determine the amount of BoNT/A protein present in pharmaceutical preparations of Botox