A Clinical Study in Participants With Huntington's Disease (HD) to Assess Efficacy and Safety of Three Oral Doses of Laquinimod

Exclusion Criteria

• •Use of immunosuppressive agents, or cytotoxic agents, including cyclophosphamide and azatioprine within 12 months prior to screening.
• •Previous use of laquinimod.
• •Use of moderate/strong inhibitors of cytochrome P450 (CYP)3A4 within 2 weeks prior to randomization.
• •Use of inducers of CYP3A4 within 2 weeks prior to randomization.
• •Pregnant or breastfeeding.
• •Participants with a clinically significant or unstable medical or surgical condition that may put the participant at risk when participating in the study or may influence the results of the study or affect the participant's ability to take part in the study, as determined by medical history, physical examinations, electrocardiogram (ECG), or laboratory tests. Such conditions may include:
• •* A major cardiovascular event (for example; myocardial infarction, acute coronary syndrome, de-compensated congestive heart failure, pulmonary embolism, coronary revascularization) that occurred prior to randomization.
• •* Any acute pulmonary disorder.
• •* A central nervous system (CNS) disorder other than HD that may jeopardize the participant's participation in the study, including such disorders that are demonstrated on the baseline MRI (based on local read).
• •* A gastrointestinal disorder that may affect the absorption of study medication.
• •* Acute or chronic renal disease including acute kidney injury (AKI).
• •* Any form of acute or chronic liver disease.
• •* Known human immunodeficiency virus (HIV) positive status. Participants will undergo an HIV test at screening per local requirements, if applicable.
• •* Any malignancies, excluding basal cell carcinoma, in the 5 years prior to randomization.
• •Any clinically significant, abnormal, screening laboratory result which in the opinion of the investigator, affects the participant' suitability for the study or puts the participant at risk if he/she enters the study.
• •Unsuitable for MRI (for example; claustrophobia, metal implants).
• •Alcohol and/or drug abuse within the 12 months prior to screening, as defined by Diagnostic and Statistical Manual of Mental Disorders - Fourth Edition Text Revision (DSM IV TR) criteria for substance abuse.
• •Participants with active suicidal ideation during the past month as measured by a most severe suicide ideation score of 4 (Active Suicidal Ideation with Some Intent to Act, without Specific Plan) or 5 (Active Suicidal Ideation with Specific Plan and Intent) on the baseline screening Columbia-Suicide Severity Rating Scale (C-SSRS) or participants who answer "Yes" on any of the 5 C-SSRS Suicidal Behavior Items (actual attempt, interrupted attempt, aborted attempt, preparatory acts, or behavior) if the attempt or acts were performed within 1 year of screening, or participants who, in the opinion of the investigator, present a serious risk of suicide.
• •Participants with known intracranial neoplasms, vascular malformations, or intracranial hemorrhage.
• •Known drug hypersensitivity that would preclude administration of laquinimod or placebo, such as hypersensitivity to mannitol, meglumine or sodium stearyl fumarate.
• •Swallowing difficulties that would preclude administration of laquinimod or placebo capsules.
• •Treatment with any investigational product within 30 days of screening or participants planning to participate in another clinical study assessing any investigational product during the study. Participants in non-interventional and/or observational studies will not be excluded from participating in this study.
• •Treatment with tetrabenazine within 30 days of the study baseline visit.
• •Treatment with antipsychotic medication within 30 days of the study baseline visit.
• •* Additional criteria may apply, please contact the investigator for more information