Double-blind, randomised, parallel group pilot study comparing two botulinum toxin type A products for the treatment of blepharospasm

Botulinum neurotoxins (BoNTs) are the primary treatment for focal dystonias such as blepharospasm. Several different BoNT products are available in various countries. Given the variability in manufacturing, formulation, and unit doses of BoNTs, it is important to compare the profiles of products from different manufacturers. This double-blind, randomised, parallel-group pilot study compared the efficacy and safety of the BoNT type A product Xeomin^® from Merz to BOTOX^® from Allergan. Subjects (n = 65) were randomly assigned to receive one or the other BoNTA in a 1:1 proportion at a dose equal to that of their most recent treatment (≥20 U/eye). Symptoms were assessed on the Blepharospasm Disability Index (BSDI), Jankovic Rating Scale (JRS), and Patient Global Assessment (PGA) scale at 4 and 8 weeks. Both BoNTA products reduced scores on the BSDI and JRS (no statistically significant difference, tendency toward greater improvements with BOTOX^® than Xeomin^® at 4 and 8 weeks). A post hoc analysis showed a significantly greater number of BOTOX^® treated patients reaching a responder threshold of 4 points on the total BSDI score and 0.67 points on the BSDI mean item score. No significant differences between products were noted in PGA and adverse events at the doses used in this study.