A 2-year open-label study of botulinum toxin type B in botulinum toxin type A resistant/responsive cervical dystonia patients (AN072-401 EU/CD)

Abstract

Objective : To evaluate the long-term safety and efficacy of repeated doses of botulinum toxin type B (BoNT-B) in patients with cervical dystonia (CD) previously naive to BoNT-B but exposed to BoNT-A. Methods : BoNT-B-naive CD patients previously exposed to BoNT-A were enrolled in this 2-year open-label study. The initial BoNT-B dose was 10,000 U and thereafter Investigators could increase/decrease the dose (maximum 25,000 U). Efficacy was assessed via a Patient Global Visual Analogue Scale (VAS) and a Treatment Assessment Scale (TAS). Safety was assessed by evaluating adverse events (AEs), clinical laboratory data and vital signs. Results : 130 BoNT-B naive patients (67 BoNT-A-resistant and 63 BoNT-A-non resistant) were enrolled. The reasons for withdrawal during the 7 sessions included: AE ( n =7), removal of consent ( n =15), failure to respond ( n =18), protocol violation ( n =1), study discontinuation ( n =5) and other ( n =6). The mean dose of BoNT-B at session 7 was 17,593U (range 10,000–25,000 U). BoNT-B demonstrated a statistically significant benefit at Week 4 in the Patient Global VAS and the TAS following each injection throughout the 2 years. No study drug-related serious AEs were reported. Moderate/severe dysphagia, xerostomia and injection site pain occurred after at least one injection in 7.7%, 23.8% and 3.1% of patients, respectively, for the first 7 treatment sessions (most after injections 1–3). Four treatment-related AEs caused withdrawal. No clinically significant changes in laboratory values or vital signs occurred. Conclusions : Repeated administration of BoNT-B therapy in CD patients who were previously naive to BoNT-B but not BoNT-A was well-tolerated and provided long-term benefit. Supported by Eisai Europe Ltd.