OnabotulinumtoxinA Displays Greater Biological Activity Compared to IncobotulinumtoxinA, Demonstrating Non-Interchangeability in Both In Vitro and In Vivo Assays.

David Rupp,Mark Washburn,Ron S Broide,Amy Brideau-Andersen,David Canty,Joanne Wang,Greg Nicholson,Wolfgang G Philipp-Dormston,Lance E Steward,Mitchell F Brin,Linh Le,Birgitte P Jacky,Catherine Rhéaume

doi:10.3390/toxins12060393

Abstract

Differences in botulinum neurotoxin manufacturing, formulation, and potency evaluation can impact dose and biological activity, which ultimately affect duration of action. The potency of different labeled vials of incobotulinumtoxinA (Xeomin®; 50 U, 100 U, or 200 U vials; incobotA) versus onabotulinumtoxinA (BOTOX®; 100 U vial; onabotA) were compared on a unit-to-unit basis to assess biological activity using in vitro (light-chain activity high-performance liquid chromatography (LCA-HPLC) and cell-based potency assay (CBPA)) and in vivo (rat compound muscle action potential (CMAP) and mouse digit abduction score (DAS)) assays. Using LCA-HPLC, incobotA units displayed approximately 54% of the protease activity of label-stated equivalent onabotA units. Lower potency, reflected by higher EC50, ID50, and ED50 values (pooled mean ± SEM), was displayed by incobotA compared to onabotA in the CBPA (EC50: incobotA 7.6 ± 0.7 U/mL; onabotA 5.9 ± 0.5 U/mL), CMAP (ID50: incobotA 0.078 ± 0.005 U/rat; onabotA 0.053 ± 0.004 U/rat), and DAS (ED50: incobotA 14.2 ± 0.5 U/kg; onabotA 8.7 ± 0.3 U/kg) assays. Lastly, in the DAS assay, onabotA had a longer duration of action compared to incobotA when dosed at label-stated equivalent units. In summary, onabotA consistently displayed greater biological activity than incobotA in two in vitro and two in vivo assays. Differences in the assay results do not support dose interchangeability between the two products.

Highlights

Botulinum neurotoxin serotype A (BoNT/A) is a highly potent toxin that causes muscle relaxation by inhibition of synaptic vesicle docking and fusion, thereby blocking acetylcholine release at neuromuscular junctions [1,2,3]
Strain [4,5], which synthesizes a complex of a 150 kDa neurotoxin, along with a group of non-toxic neurotoxin-associated proteins (NAPs)
Available BoNT/A products are in the form of a complex with varying degrees of NAPs or only as the core 150 kDa neurotoxin devoid of NAPs

Summary

Introduction

Botulinum neurotoxin serotype A (BoNT/A) is a highly potent toxin that causes muscle relaxation by inhibition of synaptic vesicle docking and fusion, thereby blocking acetylcholine release at neuromuscular junctions [1,2,3]. 1989 (BOTOX; Allergan, an AbbVie company, North Chicago, Illinois, USA; hereafter referred to as onabotA); abobotulinumtoxinA, approved in 2009 (DYSPORT® ; Ipsen Ltd., Slough, UK; hereafter referred to as abobotA); incobotulinumtoxinA, approved in 2010 (Xeomin; Merz Pharmaceuticals; Frankfurt, Germany; hereafter referred to as incobotA); and prabotulinumtoxinA-xvfs, approved in 2019 (Jeuveau® ; Evolus, Inc., Newport Beach, CA, USA; hereafter referred to as prabotA) [6]. These products are biological agents that are not chemically synthesized; as such, their compositions are structurally complex, having unique characteristics specific to each product that are key to their biological activity. OnabotA is formulated as an ~900 kDa BoNT/A complex [7,8], abobotA is formulated as an ~400 kDa BoNT/A complex [8,9,10], incobotA is formulated containing only the 150 kDa purified neurotoxin devoid of NAPs [9,11], and prabotA is formulated as a ~900 kDa

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