Efficacy and safety of incobotulinumtoxinA in post-stroke upper-limb spasticity in Japanese subjects: results from a randomized, double-blind, placebo-controlled study (J-PURE)

Background: Upper-limb spasticity frequently occurs after stroke and there is a clinical need for more effective therapies. The Phase III J-PURE study assessed the efficacy and safety of incobotulinumtoxinA up to 400 U for post-stroke upper-limb spasticity in Japan. Methods: In the 12-week main period (MP) of this double-blind, placebo-controlled study, Japanese subjects with upper-limb spasticity received one injection cycle of incobotulinumtoxinA 400 U, 250 U, or matching placebo. Eligible subjects enrolled in an open-label extension (OLEX) period of three injection cycles of incobotulinumtoxinA 400 U (32–40 weeks). The primary objective was to establish the efficacy of a single incobotulinumtoxinA injection using the Modified Ashworth Scale (MAS) wrist score. Secondary efficacy outcomes and safety were also assessed. Results: Among 100 treated subjects, AUCs for incobotulinumtoxinA 400 and 250 U were significantly different versus placebo (p = 0.0014 and p = 0.0031, respectively) for change from baseline in MAS wrist score to the end of the MP, with similar results from baseline to week 4. IncobotulinumtoxinA 400 U was superior versus placebo across other spasticity patterns and at most study visits. Improvements were maintained throughout the OLEX period. Disability Assessment Scale and Investigator’s Clinical Global Impression scores improved significantly for incobotulinumtoxinA 400 U versus placebo from baseline to week 4 (p = 0.0067 and p < 0.0001, respectively). IncobotulinumtoxinA was well tolerated up to 52 weeks, with no unexpected adverse events. Conclusion: IncobotulinumtoxinA reduced (pathologically) increased muscle tone, improved functionality and was well tolerated in Japanese subjects with post-stroke upper-limb spasticity.