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 III