Efficacy and Safety of AbobotulinumtoxinA (Dysport) for the Treatment of Hemiparesis in Adults With Upper Limb Spasticity Previously Treated With Botulinum Toxin: Subanalysis From a Phase 3 Randomized Controlled Trial

Objective: To assess the efficacy and safety of abobotulinumtoxinA in adults with upper limb spasticity previously treated with botulinum toxin A (BoNT-A). Design: A post hoc analysis from a Phase 3, prospective, double-blind, randomized, placebo-controlled study (NCT01313299). Setting: A total of 34 neurology or rehabilitation clinics in 9 countries. Participants: Adults aged 18-80 years with hemiparesis, ≥6 months after stroke or traumatic brain injury. This analysis focused on a subgroup of subjects with previous onabotulinumtoxinA or incobotulinumtoxinA treatment (n = 105 of 243 in the total trial population) in the affected limb. The mean age was 52 years, and 62% were male. Intervention: Study subjects were randomized 1:1:1 to receive a single injection session with abobotulinumtoxinA 500 or 1000 U or with placebo in the most hypertonic muscle group among the elbow, wrist, or finger flexors (primary target muscle group [PTMG]), and ≥2 additional muscle groups from the upper limb. Main Outcome Measurements: Efficacy and safety measures were assessed, including muscle tone (Modified Ashworth Scale [MAS] in the PTMG), Physician Global Assessment (PGA), perceived function, spasticity, active movement, and treatment-emergent adverse events. Results: At week 4, more subjects had ≥1 grade improvement in MAS for the PTMG with abobotulinumtoxinA versus placebo (abobotulinumtoxinA 500 U, 81.1%; abobotulinumtoxinA 1000 U, 75.0%; placebo, 25.0%). PGA scores ≥1 were achieved by 75.7% and 87.5% of abobotulinumtoxinA 500 and 1000 U subjects versus 41.7% with placebo. Perceived function (Disability Assessment Scale), spasticity angle (Tardieu Scale), and active movement were also improved with abobotulinumtoxinA. There were no treatment-related deaths or serious adverse events. Conclusions: The efficacy and safety of abobotulinumtoxinA in subjects previously treated with BoNT-A were consistent with those in the total trial population. Hence, abobotulinumtoxinA is a treatment option in these patients, and no difference in initial dosing appears to be required compared to that in individuals not treated previously. Level of Evidence: I.