Abobotulinumtoxina (Dysport®): Doses Used to Treat Upper Limb Muscles of Adults with Spasticity Participating in a Phase III Randomized, Double-Blind Placebo- Controlled Study

Introduction/Background: In a Phase III, randomized, double-blind placebo-controlled study conducted in 34 sites from 9 countries, two doses of abobotulinumtoxinA (Dysport®) 500 and 1000 units (U) were shown to be efficacious on muscle tone for the treatment of hemiparetic adults post stroke or traumatic brain injury (TBI) with a favourable safety profile.1. Materials and Methods: 243 patients received abobotulinumtoxinA 500 or 1000 U or placebo by intramuscular injection into their primary targeted muscle group (PTMG, selected from extrinsic finger flexors, wrist flexors and elbow flexors) and at least two other upper limb muscles, including shoulder muscles. Treatment was administered in a volume of 5.0 mL using electrostimulation. Doses administered to upper limb muscles are reported here. Results: For the abobotulinumtoxinA 500 U group, mean (SD) doses (U) administered in fingers flexors were: 93.5 (17.0) for flexor digitorium profundus (FDP), 95.4 (14.3) for flexor digitorium superficialis (FDS) and 76.9 (26.8) for other finger flexors (flexor pollis longus, adductor pollicis); in wrist flexors: 92.2 (18.1) for flexor carpi radialis (FCR) and 89.9 (25.7) for flexor carpi ulnaris (FCU); in elbow flexors: 88.3 (28.5) for brachioradialis, 148.5 (60.2) for brachialis and 108.6 (49.5) for other elbow muscles (biceps brachii, pronator teres) and 122.2 (44.1) in shoulder muscles (triceps brachii, pectoralis major, subscapularis, latissimus dorsi). For the abobotulinumtoxinA 1000 U group, doses administered were 195.5 (25.9) for FDP, 196.8 (28.4) for FDS, 157.0 (53.3) for other finger flexors, 178.1 (45.5) for FCR, 171.2 (45.2) for FCU, 172.1 (44.8) for brachioradialis, 321.4 (103.2) for brachialis, 216.5 (92.2) for other elbow muscles and 300.0 (129.1) in shoulder muscles. Conclusion: In this Phase III worldwide study in hemiparetic patients with upper limb spasticity post stroke/TBI, mean doses administered were 76.9–196.8 U for muscles in the finger flexors, 89.9-178.1 U for muscles in wrist flexors, 88.3–321.4 U for muscles in the elbow flexors and 122.2–300.0 U in shoulder muscles. Total dose administered (in the PTMG and at least 2 upper limb muscles) was 500 or 1000 U, which was previously shown to improve muscle tone in this patient population.