The effects of repeated dosing of botulinum toxin type B (neurobloc ®) in patients with cervical dystonia previously naïve to botulinum toxin: An open-label extension study (AN072-402 EU/CD)

Abstract

Objective: To evaluate the safety and efficacy of repeated doses of botulinum toxin type B (BoNT-B) in patients with cervical dystonia (CD) previously naive to BoNT. Methods: BoNT-naive CD patients completing a double-blind, comparator (BoNT-A vs. BoNT-B) phase continued in this open-label (OL) extension study. All OL patients received 10,000 U BoNT-B. Investigators could then modify dose by 5000 U increments/decrements during the subsequent 5 sessions (range 5000–25,000 U). Efficacy was assessed via Patient Global Visual Analogue Scale (VAS), and safety by evaluating adverse events (AEs), clinical laboratory data and vital signs. Results: 94 patients (45 and 49 had received BoNT-B and BoNT-A, respectively, during the previous double-blind study) were enrolled. 55 patients (58%) completed 6 OL treatment sessions (TS). Reasons for withdrawal included: AE (n=4); transportation/lost to follow-up (n=11); lack of efficacy (n=9); subject/sponsor decision (n=11); or other (n=4). Mean BoNT-B dose at TS 6 was 15,170 U (range 5000–25,000 U). BoNT-B demonstrated statistically significant benefit at Week 4 in the Patient Global VAS following each TS injection. No drug-related serious AEs were reported. Four subjects experienced 9 AEs leading to withdrawal: only dry mouth in 1 subject and fatigue, anorexia, influenza-like illness, and nausea in another subject were considered study drug-related. Moderate or severe dysphagia and dry mouth occurred in 9.6% and 16.0% of patients, respectively. No clinically significant changes in laboratory values or vital signs occurred. Conclusions: Repeated administration of BoNT-B provided persistent benefit and was well-tolerated in patients with CD previously naive to BoNT treatment. Supported by Eisai Europe Ltd.