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Objective:To demonstrate single abobotulinumtoxinA injection efficacy in lower limb vs placebo for adults with chronic hemiparesis and assess long-term safety and efficacy of repeated injections.Methods:In a multicenter, double-blind, randomized, placebo-controlled, single-cycle study followed by a 1-year open-label, multiple-cycle extension, adults ≥6 months after stroke/brain injury received one lower limb injection (abobotulinumtoxinA 1,000 U, abobotulinumtoxinA 1,500 U, placebo) followed by ≤4 open-label cycles (1,000, 1,500 U) at ≥12-week intervals. Efficacy measures included Modified Ashworth Scale (MAS) in gastrocnemius–soleus complex (GSC; double-blind primary endpoint), physician global assessment (PGA), and comfortable barefoot walking speed. Safety was the open-label primary endpoint.Results:After a single injection, mean (95% confidence interval) MAS GSC changes from baseline at week 4 (double-blind, n = 381) were as follows: −0.5 (−0.7 to −0.4) (placebo, n = 128), −0.6 (−0.8 to −0.5) (abobotulinumtoxinA 1,000 U, n = 125; p = 0.28 vs placebo), and −0.8 (−0.9 to −0.7) (abobotulinumtoxinA 1,500 U, n = 128; p = 0.009 vs placebo). Mean week 4 PGA scores were as follows: 0.7 (0.5, 0.9) (placebo), 0.9 (0.7, 1.1) (1,000 U; p = 0.067 vs placebo), and 0.9 (0.7, 1.1) (1,500 U; p = 0.067); walking speed was not significantly improved vs placebo. At cycle 4, week 4 (open-label), mean MAS GSC change reached −1.0. Incremental improvements in PGA and walking speed occurred across open-label cycles; by cycle 4, week 4, mean PGA was 1.9, and walking speed increased +25.3% (17.5, 33.2), with 16% of participants walking >0.8 m/s (associated with community mobility; 0% at baseline). Tolerability was good and consistent with the known abobotulinumtoxinA safety profile.Conclusions:In chronic hemiparesis, single abobotulinumtoxinA (Dysport Ipsen) administration reduced muscle tone. Repeated administration over a year was well-tolerated and improved walking speed and likelihood of achieving community ambulation.Clinicaltrial.gov identifiers:NCT01249404, NCT01251367.Classification of evidence:The double-blind phase of this study provides Class I evidence that for adults with chronic spastic hemiparesis, a single abobotulinumtoxinA injection reduces lower extremity muscle tone.

Introduction: The efficacy of single injections of abobotulinumtoxinA (Dysport) is established in adults with upper limb spasticity. In this study we assessed the effects of repeated injections of abobotulinumtoxinA over 1 year. Methods: Patients (n = 258, safety population) received 500 U, 1,000 U, or 1,500 U (1,500‐U dose included 500‐U shoulder injections) for up to 4 or 5 treatment cycles. Assessments included treatment‐emergent adverse events (TEAEs), muscle tone, passive and active range of motion (XV1, XA), angle of catch (XV3), Disability Assessment Scale (DAS) score, Modified Frenchay Scale (MFS) score, and Physician Global Assessment (PGA) score. Results: The incidence of TEAEs decreased across cycles. Muscle tone reduction and XV1 remained stable across cycles, whereas XV3 and XA continued to improve at the finger, wrist, and elbow flexors. DAS and PGA improved across cycles. MFS improved best with 1,500 U. Discussion: A favorable safety profile and continuous improvements in active movements and perceived and active function were associated with repeated abobotulinumtoxinA injections in upper limb muscles. Muscle Nerve 57: 245–254, 2018

BACKGROUND: Although botulinum toxin is a well-established treatment of focal spasticity in cerebral palsy, most trials have been small, and few have simultaneously assessed measures of muscle tone and clinical benefit.

Botulinum neurotoxin type-A (BoNT-A) blocks the release of acetylcholine from peripheral cholinergic nerve terminals and is an important option for the treatment of disorders characterised by excessive cholinergic neuronal activity. Several BoNT-A products are currently marketed, each with unique manufacturing processes, excipients, formulation, and non-interchangeable potency units. Nevertheless, the effects of all the products are mediated by the 150 kDa BoNT-A neurotoxin. We assessed the quantity and light chain (LC) activity of BoNT-A in three commercial BoNT-A products (Dysport®; Botox®; Xeomin®). We quantified 150 kDa BoNT-A by sandwich ELISA and assessed LC activity by EndoPep assay. In both assays, we assessed the results for the commercial products against recombinant 150 kDa BoNT-A. The mean 150 kDa BoNT-A content per vial measured by ELISA was 2.69 ng/500 U vial Dysport®, 0.90 ng/100 U vial Botox®, and 0.40 ng/100 U vial Xeomin®. To present clinically relevant results, we calculated the 150 kDa BoNT-A/US Food and Drug Administration (FDA)-approved dose in adult upper limb spasticity: 5.38 ng Dysport® (1000 U; 2 × 500 U vials), 3.60 ng Botox® (400 U; 4 × 100 U vials), and 1.61 ng Xeomin® (400 U; 4 × 100 U vials). EndoPep assay showed similar LC activity among BoNT-A products. Thus, greater amounts of active neurotoxin are injected with Dysport®, at FDA-approved doses, than with other products. This fact might explain the long duration of action reported across multiple indications, which benefits patients, caregivers, clinicians, and healthcare systems.