Xeomin® in the treatment of cervical dystonia

Background and purpose: Botulinum toxin type A (BoNT/A) is a highly effective and well-tolerated treatment for focal dystonias. The BoNT/A in Botox (R) and Dysport (R) is part of a high-molecular-weight complex that contains hemagglutinins and other non-toxic proteins, whilst Xeomin (R) is a highly purified BoNT/A free of such complexing proteins. In the largest controlled study of BoNT/A published to date (Neurology 2005; 64: 1949), it was demonstrated that Xeomin (R) is non-inferior to Botox (R) and has 1:1 efficacy in the treatment of cervical dystonia. A possible limitation of continued BoNT/A treatment is antibody development. Based on its physiochemical properties and toxicological evidence, Xeomin (R) is expected to have a reduced incidence of non-responders after long-term treatment compared with other marketed BoNT/A products. Methods and results: In our ongoing open-label study, 100 patients suffering from cervical dystonia are continuously treated with Xeomin (R); 50 patients were treated de novo, the remaining patients had been previously treated with Botox (R), Dysport (R) or NeuroBloc (R)/Myobloc (R). All patients showed negative results in antibody testing at the beginning of Xeomin (R) treatment. During continuous treatment with Xeomin (R) up to 2 years, patients continued to respond well to Xeomin (R) treatment. Conclusion: The treatment was well tolerated and no patient has developed neutralizing antibodies as measured using the sensitive mouse hemidiaphragma assay within these first 2 years.