Disclosures: Keith A Foster, FRSB: Ipsen: Employment

Objective: Assess clinical treatment intervals for abobotulinumtoxinA in the management of adult and pediatric spasticity and assess preclinical data that might explain differences in the clinical profiles of botulinum toxin-A (BoNT-A) products.

Design: Review of Phase III studies (adult upper limb [AUL], adult lower limb [ALL] and pediatric lower limb [PLL]) with abobotulinumtoxinA and preclinical studies comparing the quantity and activity of active toxin in commercially available BoNT-A products.

Setting: Phase III studies were conducted in specialist centres.

Participants: AUL and ALL: Hemiparetic adult patients with upper/lower limb spasticity due to stroke or TBI. PLL: children (2-17 years) with dynamic equinus due to cerebral palsy

Interventions: AUL: AbobotulinumtoxinA 500U, 1000U & 1500U; ALL: AbobotulinumtoxinA 1000U & 1500U; PLL: AbobotulinumtoxinA 10U/kg/leg & 15U/kg/leg.

Main Outcome Measures: Time to retreatment as assessed at Weeks 12, 16, 20, 24 in the adult studies and Weeks 12, 16, 22, 28 in the PLL study.

Results: At doses tested, a long duration of response was observed. Pivotal studies of abobotulinumtoxinA reveal a large proportion of patients did not require retreatment for >12 weeks (% patients injected Week-16 or later: AUL: 35%; ALL: 20.1%; PLL: 74.0%). Safety was as expected for BoNT-A and rates of seroconversion for neutralizing antibodies were low (≤4.3%), with no evidence of secondary non-responsiveness. Pre-clinical research has established BoNT-A duration of response to be dose-dependent. Research showed no differences in relative molecular activity of BoNT-A products, but more active neurotoxin in abobotulinumtoxinA (at total FDA recommended doses for ALL/AUL & total tested doses for PLL) than either onabotulinumtoxinA or incobotulinumtoxinA.

Conclusions: AbobotulinumtoxinA, when dosed optimally, offers patients a long duration of response with sustained symptom relief between injections. We hypothesize that clinically observed long duration of abobotulinumtoxinA response is a result of the amount of active BoNT-A.

Level of Evidence: Level I

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/abobotulinumtoxina-evidence-for-long-duration-of-response/