HT-3951 vs. Placebo in Stroke Rehabilitation

Main Inclusion Criteria: * Age range between 21 to 85 years, inclusive, at the Screening Visit * Subjects who have experienced an ischemic stroke documented by CT or MRI resulting in an upper extremity deficit that, in the opinion of the Investigator, warrants the need for rehabilitation therapy * Medically stable subjects who are able to be randomized to study medication beginning between ≥ 2 and ≤ 52 weeks post-stroke * Subjects who have initiated, are undergoing, have completed or agree to begin physical or occupational rehabilitation for at least 2 weeks prior to study Day 1. * Mild to moderate unilateral upper extremity motor impairment characterized by FMA-EU score of \> 18 * Modified Rankin Scale score of 1 to 4 Main Exclusion Criteria: * History of stroke within 6 months prior to the subject's current episode of ischemic stroke (History of transient ischemic attacks or ischemic stroke (nonhemorrhagic) more than 6 months prior to the current ischemic stroke are acceptable.) * Subjects with unresolved upper or lower motor deficits (e.g., range of motion or strength deficits) from any prior stroke * Significant hemorrhagic stroke * Any history of seizure disorder or a spontaneous seizure that had occurred at any time after the stroke * Apraxia that, in the Investigator's opinion, would likely reduce the ability of the subject to participate in the study or confound study outcome measures * Moderate to severe aphasia and/or severe language deficits * Severe sensory loss in affected hand * Moderate to severe hemispatial neglect or anosognosia involving the affected arm * Absent proprioception at the elbow or shoulder joints * Excessive spasticity in the affected elbow, defined as a score of greater than or equal to 3 on the Modified Ashworth Spasticity scale (MAS)