• Change in MAS wrist score
• Change from baseline in MAS wrist score
• Change from baseline in DAS score
• Global impression of therapeutic benefit of GSK1358820 to rehabilitation if any change is made to permissible concomitant rehabilitation therapy during the open-label phase.

• Efficacy: MAS, Disability Assessment Scale (DAS), Clinical Global Impression (CGI) Safety: Adverse events, clinical laboratory tests, pulse rate, blood pressure, 12-lead ECG, pulmonary function tests
• An area under the curve (AUC) based on the change from baseline in MAS wrist score in the low dose groups during the double-blind phase.
• Change from baseline in MAS finger score
• Change from baseline in CGI of functional disability

• Efficacy:
• MAS, Disability Assessment Scale (DAS), Clinical Global Impression (CGI)
• Safety:
• Adverse events, clinical laboratory tests, pulse rate, blood pressure, 12-lead ECG, pulmonary function tests

This is a study to confirm the superior efficacy of a single treatment of GSK1358820 over placebo in patients with post-stroke upper limb spasticity of both the wrist and finger flexors using the Modified Ashworth Scale (MAS) wrist score.

Inclusion Criteria:

• Subjects eligible for enrollment in the study must meet all of the following criteria:

  1) Patients with upper limb spasticity who are at least 6 months post stroke and present with spasticity of both the wrist and fingers at the start of double-blind phase (Visit 2).

• Wrist flexor muscle tone of ≥ 3 and finger flexor muscle tone of ≥ 2 on the MAS, and at least one functional disability item (i.e., hygiene, pain, dressing or limb posture) with a rating of ≥ 2 on the DAS at the start of double-blind phase (Visit 2).
• Male or female between 20 and 80 years of age at the time of informed consent. For males, only those who can practice contraception during the study period are eligible.
• ≥ 40kg in weight at the start of double-blind phase (Visit 2).
• Inpatient or outpatient; however, the hospitalization status must remain unchanged during the double-blind phase.
• Written informed consent from the subject him/herself. If the subject's signature is not legible, the attendance of a witness is required.

Exclusion Criteria:

• A subject will not be eligible for inclusion in this study if any of the following criteria apply:
• Bilateral hemiplegia or quadriplegia.
• Presence of fixed contractures of the wrist and/or fingers (absence of range of motion).
• Profound atrophy of the muscles to be injected.
• Previous surgical intervention, phenol block, ethanol block, or muscle afferent block (MAB) for wrist and/or finger spasticity.
• Casting of the study upper limb within 3 months prior to the start of double-blind phase (Visit 2).
• Current treatment with intrathecal baclofen.
• Use of peripheral muscle relaxants (dantrolene sodium, suxamethonium chloride, pancuronium bromide, vecuronium bromide).
• Concurrent use of antibiotics that interfere with neuromuscular transmission, such as aminoglycoside antibiotics (e.g., streptomycin sulfate, kanamycin sulfate, gentamicin sulfate, neomycin sulphate, spectinomycin hydrochloride), polypeptide antibiotics (e.g., polymixin B sulfate), lincomycin antibiotics (e.g., lincomycin hydrochloride, clindamycin), and enviomycin sulfate.
• Previous botulinum toxin therapy.
• Diagnosis of systemic neuromuscular disorders (e.g., myasthenia gravis, Lambert-Eaton syndrome, amyotrophic lateral sclerosis).
• Females who are pregnant, nursing, may be pregnant, or planning a pregnancy during the study period.
• Known allergy or hypersensitivity to any ingredient of study medication (e.g., human serum albumin).
• Presence of psychiatric disorder or impairment of intellectual function that may interfere with the subject's ability to give informed consent or the conduct of the study.
• Bedridden patients.
• Presence of clinically unstable severe cardiovascular disease.
• Presence of clinically significant severe renal, hepatic or respiratory disease.
• Infection or dermatological condition at the proposed injection sites.
• Previous or planned participation in another clinical study (including the lower limb spasticity study of GSK1358820) within 6 months prior to the start of double-blind phase (Visit 2).
• Others whom the investigator or sub investigator considers not eligible for the study.