Editorial Comment

Abstract

In therapy with botulinum toxin type A (BoNT/A), antibodies against BoNT/A (BoNT/A-AB) may be a reason for a complete secondary therapy failure.1 Currently, approximately 5% of patients with cervical dystonia that are receiving repeated BoNT/A injections have complete secondary therapy failure due to BoNT/A-AB.2 This manuscript is interesting and the first paper to investigate BoNT/A-AB in patients receiving BoNT/A injections at the lower urinary tract.3 The study demonstrates that the incidence of BoNT/AB was 16% after treatment and there was no correlation between the presence of BoNT/A-AB and the total number of previous injections. It is unclear why the prevalence of BoNT/A-AB was much higher in bladder injections than that in other fields. On these points this study is very interesting; however, there are some shortcomings. This study clearly demonstrated that BoNT/A-AB can develop after injections to the lower urinary tract. However, the results of this study cannot conclude that antibodies will cause therapeutic failure. Objective success was noted in seven patients, in whom one had antibodies (14%); and objective failure was noted in 11 patients, in whom three had antibodies (27%). It is difficult to conclude that BoNT/A-AB has a direct association with therapeutic failure in this study. In neurology, re-injection at too short intervals contributes to BoNT/A resistance. Therefore, they recommended ‘drug holiday’ to prevent BoNT/A-AB.4 What should we do if patients become clinically non-responsive to BoNT/A? Botulinum toxin type B might be effective to such patients.5 In the future, application of a new BoNT/A preparation with low antigenic potency might be a promising treatment option.6