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).

The primary purpose is to prove the efficacy of treatment administration with Botulinum Toxin Type A for Injection (HengLi®) beyond placebo in subjects with post-stroke upper limb spasticity of both wrist and fingers flexors as measured on the Modified Ashworth Scale (MAS).

Subjects will receive a single treatment session of intramuscular HengLi® 200U or 240U (if thumb spasticity is present) or placebo after they first enroll the core phase randomly. Totally 180 subjects will be recruited in this part. Each completed subject should finish 8 (visit 0 to 7) clinic visits. Subjects will receive a single intramuscular treatment with either HengLi® or placebo at day 0 (visit 0). The else 7 visits are at week 1, 4, 6, 8, 12, 16 and 18 (visits 1 to 7) and week 6 (visit 3) is appointed as the primary visit to determine efficacy.

The primary endpoint is the change from baseline at week 6 for wrist flexor muscle tone as measured on the Modified Ashworth Scale (MAS). The secondary endpoints involve the area under curve (AUC) for the MAS wrist score change from baseline, change from baseline for wrist/finger/thumb flexor muscle tone as measured on MAS, DAS and GAS. The safety measures involve adverse events, clinical laboratory tests and pulse, blood pressure.

Inclusion Criteria:

• ≥40kg in weight.
• Subjects voluntarily sign the informed consent.
• Subjects with upper limb spasticity who are at least 3 months post stroke and present with spasticity of both the wrist and fingers in the study limb.
• Both wrist flexor muscle tone and finger flexor muscle tone evaluation recorded 2 or greater individually as measured by MAS (0 to 4).
• At least one functional disability item (i.e., hygiene, dressing, pain, or cosmesis) evaluated 2 or greater by DAS (0 to 3).
• If using oral anti-spasticity medications, must be stable for at least 1 month prior to study enrolment.
• If taking any physical therapy or occupational therapy, must be stable on frequency, type, and intension for at least 1 month prior to study enrolment.
• In the opinion of the investigator, subject must clearly understand the intent of the study and be willing and able to comply with study instructions and complete the entire study.

Exclusion Criteria:

• Females who are pregnant, nursing, or planning a pregnancy during the study period, or females of childbearing potential, not using a reliable means of contraception.
• Known allergy or sensitivity to study medication or its components.
• Infection or dermatological condition at the injection sites.
• Significant inflammation in the study limb limiting joint movement.
• Unstable liver disease (as defined by the presence of ascites, encephalopathy, coagulopathy, hypoalbuminaemia, esophageal or gastric varices or persistent jaundice), cirrhosis, known biliary abnormalities (with the exception of Gilbert's syndrome or asymptomatic gallstones).
• History of or planned surgical intervention for spasticity of the study limb.
• Participation in another clinical study currently, or within the one months immediately prior to enrolment.
• Within six months prior to the study had received any treatment of patients with botulinum toxin of any serotype.
• Any medical condition that may put the subject at increased risk with exposure , including diagnosed myasthenia gravis, Eaton-Lambert syndrome, amyotrophic lateral sclerosis, or any other disorder that might have interfered with neuromuscular function.
• History of or planned treatment for spasticity with phenol or alcohol block in the study limb.
• Current treatment for spasticity with an intrathecal baclofen.
• QTc criteria: (either QTcb or QTcf, machine or manual overread, males or females); include the following details as appropriate: QTc≥450 millisecond (msec) or≥480msec for subjects with Bundle Branch Block-values based on either single electrocardiogram (ECG) values or triplicate ECG averaged QTc values obtained over a brief recording period.
• Liver function tests: aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≥2xULN; alkaline phosphatase and bilirubin >1.5xULN (isolated bilirubin >1.5ULN is acceptable if bilirubin is fractionated and direct bilirubin <35%).
• Concurrent use of aminoglycoside antibiotics or other agents that might interfere with neuromuscular function.
• Presence of clinically unstable severe cardiovascular, renal or respiratory disease.
• Profound atrophy of muscles to be injected (in the investigators opinion).
• Planned or anticipated initiation of new antispasticity medications during the clinical study.
• History (within 3 months of qualification) of or planned (during study period) casting of the study limb.
• patients with severe cognitive impairment or neurological diseases affecting the implementation or evaluation of the test, and drug-dependent patients.
• Researchers believe there are other factors unfit to participate in this study of patients .