Respective potencies of Botox and Dysport: a double blind, randomised, crossover study in cervical dystonia
- 1Service de Neurologie, Hôf.pital Sainte-Anne, Paris, France
- 2Pharmacie, Hôf.pital Sainte-Anne, Paris, France
- 3Département de statistiques, Hôf.pital Salvator, Marseille, France
- Correspondence to: Dr D Ranoux, Service de Neurologie, Hô;f.pital Sainte-Anne, 1 rue Cabanis, 75 674 Paris Cedex 14, France; ranoux{at}chsa.broca.inserm.fr
- Received 30 May 2001
- Accepted 5 November 2001
- Revised 17 September 2001
Abstract
Objectives: Botulinum toxin type A is a potent neuromuscular paralyzing agent used in various disorders including cervical dystonia. Two preparations of botulinum toxin are now commercially available ( Dysport and Botox), but much controversy remains about their respective potencies. The aim of the study was to compare the efficacy of Botox with two different ratios of Dysport.
Methods: A double blind, randomised, three period cross over study involving 54 patients with cervical dystonia was performed. The patients received the following treatments in a randomised order: Botox at the usually effective dose, Dysport at a dose of 1:3 (conversion factor of 3 between Botox and Dysport units—that is, one Botox unit=three Dysport units) and at a dose of 1:4 (conversion factor of four). The improvement of the Tsui (primary outcome criteria) and of the TWSTRS pain scales between baseline and a control visit 1 month after each of the three injections, as well as the incidence of adverse events, were assessed.
Results: Comparison of the Tsui scores and of the TWSTRS pain scores showed a better effect on impairment and pain with Dysport 1:3 (p=0.02 and 0.04, respectively) and 1:4 (p=0.01 and 0.02, respectively) than with Botox. The number of adverse events was higher with both Dysport treatments. The most frequent adverse event was dysphagia, found in 3%, 15.6%, and 17.3% (Botox, Dysport 1:3 and 1:4, respectively) of the patients. No adverse event required withdrawal of therapy or specific management.
Conclusions: Dysport 1:3 (and Dysport 1:4 to a greater extent) is more efficient than Botox for both impairment and pain in cervical dystonia although with a somewhat higher incidence of minor adverse effects. This strongly suggests that the most appropriate conversion factor between Botox and Dysport units is less than 3 in cervical dystonia.
