Clinical bioequivalence of the current commercial preparations of Botulinum toxin

In an attempt to obtain the clinical bioequivalence of the two commercial preparations of botulinum toxin (BOTOX(R) and Dysport(R)), we performed an open label study to evaluate the effective dose of the two toxins in 60 patients (blepharospasm: 26; hemifacial spasm: 34). To determine the minimal effective dose, injections were repeated monthly until at least a 50% improvement was apparent for one month. The optimal dose was then evaluated using a cross-over study with a six-month wash-out period between injections of the two toxins. The same procedures were used when injecting the toxins; the dilutions were 2.5 U/0.1 ml and 20 U/0.1 ml for BOTOX(R) and Dysport(R), respectively. The results suggest that the clinical equivalence of 1 unit of BOTOX(R) is 5.3-6.0 units of Dysport(R).