A Study to Evaluate the Botulinum Toxin Type A for Injection(HengLi®) in Subjects With Post-stroke Upper Limb Spasticity

This is a multicenter, double-blind, randomized, placebo-controlled study designed to compare Botulinum Toxin Type A for Injection (HengLi®) with placebo on the efficacy and safety of treatment in post-stroke subjects with focal wrist, finger and in some cases, thumb spasticity. Approximately 180 subjects will be enrolled. The core period of the subjects will receive a single treatment session of intramuscular HengLi® 200U or 240U (if thumb spasticity is present) or placebo in a randomization ratio of 2:1. Research contains two parts: core phase and extension phase. In the core phase, subjects will finish 6 visits (12 weeks ) after initial injection. During the extension phase, subjects will accept two follow-up visit (6 weeks). Outcome measures include changes from baseline at every post injection visit as measured on the Modified Ashworth Scale (MAS), Disability Assessment Scale (DAS) and Global Assessment Scale(GAS). The primary efficacy endpoint is the change from baseline at week 6 for wrist flexor muscle tone as measured on the Modified Ashworth Scale. Safety parameters will also be measured including adverse events, vital signs (pulse and blood pressure) and clinical laboratory tests (haematology, serum chemistry and urinanalysis).