The ONTIME study investigated whether early post-stroke abobotulinumtoxinA injection delays appearance or progression of upper limb spasticity (ULS) symptoms. ONTIME (NCT02321436) was a 28-week, exploratory, double-blind, randomized, placebo-controlled study of abobotulinumtoxinA 500U in patients with ULS (Modified Ashworth Scale [MAS] score ≥ 2) 2–12 weeks post-stroke. Patients were either symptomatic or asymptomatic (only increased MAS) at baseline. Primary efficacy outcome measure: time between injection and visit at which re-injection criteria were met (MAS ≥ 2 and ≥1, sign of symptomatic spasticity: pain, involuntary movements, impaired active or passive function). Forty-two patients were randomized (abobotulinumtoxinA 500U: n = 28; placebo: n = 14) with median 5.86 weeks since stroke. Median time to reach re-injection criteria was significantly longer for abobotulinumtoxinA (156 days) than placebo (32 days; log-rank: p = 0.0176; Wilcoxon: p = 0.0480). Eleven (39.3%) patients receiving abobotulinumtoxinA did not require re-injection for ≥28 weeks versus two (14.3%) in placebo group. In this exploratory study, early abobotulinumtoxinA treatment significantly delayed time to reach re-injection criteria compared with placebo in patients with post-stroke ULS. These findings suggest an optimal time for post-stroke spasticity management and help determine the design and sample sizes for larger confirmatory studies.

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IntroductionApproximately 15 million people suffer a stroke annually, up to 40% of which may develop spasticity, which can result in impaired limb function, pain and associated involuntary movements affecting motor control.Robust clinical data on spasticity progression, associated symptoms development and functional impairment is scarce. Additionally, maximal duration of muscle tone reduction following botulinum toxin type A (BoNT-A) injections remains undetermined. The ONTIME pilot study aims to explore these issues and evaluate whether abobotulinumtoxinA 500 U (Dysport®; Ipsen) administered intramuscularly within 12 weeks following stroke delays the appearance or progression of symptomatic (disabling) upper limb spasticity (ULS).MethodsONTIME is a 28-week, phase 4, randomised, double-blind, placebo-controlled, exploratory pilot study initiated at four centres across Malaysia, the Philippines, Singapore and Thailand. Subjects (n = 42) with moderate to severe ULS (modified Ashworth scale [MAS] score ≥2) in elbow flexors or pronators, wrist flexors, or finger flexors will be recruited. Subjects will be randomised 2:1 to abobotulinumtoxinA 500 U or placebo (single dose 2–12 weeks after first-ever stroke).Primary efficacy will be measured by time between initial injection and visit at which reinjection criteria (MAS score ≥2 in the primary targeted muscle group and appearance or reappearance of symptomatic ULS) are met. Follow-up visits will be 4-weekly to a maximum of 28 weeks.DiscussionThis pilot study will facilitate the design and sample size calculation of further confirmatory studies, and is expected to provide insights into the optimal management of post-stroke patients, including timing of BoNT-A therapy and follow-up duration.