IncobotulinumtoxinA (Xeomin(®)) can produce antibody-induced therapy failure in a patient pretreated with abobotulinumtoxinA (Dysport(®)).

IncobotulinumtoxinA has not produced a single case of antibody-induced therapy failure after 8 years of worldwide usage. We are reporting a patient with progressive hereditary juvenile onset generalised dystonia who was pretreated with abobotulinumtoxinA for 15 years, before she received incobotulinumtoxinA. To the fifth and sixth applications, she responded with complete therapy failure. Mouse hemidiaphragm assay testing revealed a maximal botulinum toxin antibody titre. Improved specific biological activity and lack of complexing proteins seem to reduce the antigenicity of incobotulinumtoxinA. However, this first ever report indicates that it does not eliminate it entirely.