An AE is any untoward medical occurrence in a patient or clinical investigation patient administered a pharmaceutical product, which does not necessarily have a causal relationship with this treatment. An AE can therefore be any unfavorable or unintended sign (including an abnormal laboratory finding), symptom, or disease temporarily associated with the use of medicinal product, whether or not considered related to the investigational medicinal product.

A Serious Adverse Event (SAE) is any untoward medical occurrence that at any dose results in death, is life-threatening (defined as an event in which the subject was at risk of death at the time of the event; it does not refer to an event which hypothetically might have caused death if it were more severe), requires inpatient hospitalization or causes prolongation of existing hospitalization.

An AE is any untoward medical occurrence in a patient or clinical investigation patient administered a pharmaceutical product, which does not necessarily have a causal relationship with this treatment. An AE can therefore be any unfavorable or unintended sign (including an abnormal laboratory finding), symptom, or disease temporarily associated with the use of medicinal product, whether or not considered related to the investigational medicinal product.

An AE is any untoward medical occurrence in a patient or clinical investigation patient administered a pharmaceutical product, which does not necessarily have a causal relationship with this treatment. An AE can therefore be any unfavorable or unintended sign (including an abnormal laboratory finding), symptom, or disease temporarily associated with the use of medicinal product, whether or not considered related to the investigational medicinal product.

An AE is any untoward medical occurrence in a patient or clinical investigation patient administered a pharmaceutical product, which does not necessarily have a causal relationship with this treatment. An AE can therefore be any unfavorable or unintended sign (including an abnormal laboratory finding), symptom, or disease temporarily associated with the use of medicinal product, whether or not considered related to the investigational medicinal product.

An absolute lymphocyte count (ALC) is a part of a blood test that measures the number of lymphocytes, a type of white blood cell, in the blood. Lymphocytes help fight infections and diseases. Reductions in ALC levels for participants in this study is expected and is a primary pharmacodynamic effect of RPC1063. LLN = Lower limit of normal

A white blood cell count is a part of a blood test that measures the number of white blood cells in the blood. White blood cells help fight infections and diseases. LLN = Lower limit of normal

An absolute neutrophil count is a part of a blood test that measures the number of neutrophils, a type of white blood cell, in the blood. Neutrophils help fight infections and diseases.

The number of participants with laboratory abnormalities in specific liver tests above ULN by category. ULN = Upper Limit of Normal

An electrocardiogram (ECG) measures electrical activity of the heart to detect cardiac problems.

Vital signs included body temperature, sitting heart rate/pulse (HR), sitting systolic blood pressure (SBP), sitting diastolic blood pressure (DBP). Baseline refers to assessments made on or before the first day participants received study treatment.

The number of participants with abnormal physical examination results. The assessments included abdominal, extremity, head, heart, lungs, neck, neurological non-MS, other and skin assessments. Baseline refers to assessments made on or before the first day participants received study treatment.

The Columbia-Suicide Severity Rating Scale (C-SSRS) is a unique suicide risk assessment tool that supports suicide risk assessment through a series of simple, plain-language questions. The answers help users identify whether someone is at risk for suicide, assess the severity and immediacy of that risk, and gauge the level of support that the person needs. Results are displayed as the number of participants who answered "Yes" to at least one of the 10 questions in the suicidal ideation or suicidal behavior section. Ideation from 1 (wishing to be dead) - 5 (Active suicidal ideation with specific plan and intent) Behavior from 6 (Preparatory acts or behavior) - 10 (Completed suicide). Baseline refers to assessments made on or before the first day participants received study treatment.

The Columbia-Suicide Severity Rating Scale (C-SSRS) is a unique suicide risk assessment tool that supports suicide risk assessment through a series of simple, plain-language questions. The answers help users identify whether someone is at risk for suicide, assess the severity and immediacy of that risk, and gauge the level of support that the person needs. Results are displayed as the number of participants who answered "Yes" to at least one of the 10 questions in the suicidal ideation or suicidal behavior section. Ideation from 1 (wishing to be dead) - 5 (Active suicidal ideation with specific plan and intent) Behavior from 6 (Preparatory acts or behavior) - 10 (Completed suicide).

The PWC-20 is a rater-administered 20-item scale to assess signs and symptoms of withdrawal. Twenty items are rated on a 4-point scale as not present (0 points), mild (1 point), moderate (2 points), or severe (3 points). The points from all items are calculated as a total score. Higher scores indicate more severe withdrawal symptoms.

The HADS is a validated patient reported outcome for assessing anxiety and depression. It consists of 14 items in total, 7 items related to anxiety and 7 items related to depression. For each item patients select a statement (valued at 0 to 3 points) that closest matches their own feeling over the past week. Separate total scores for anxiety and depression are derived by adding up points. Total scores can range from 0 to 21 points. Higher scores indicate more severe anxiety and depression and scores of 8 to 10 are generally considered indicative of borderline anxiety/depression disorders and scores of 11 and higher are generally considered indicative of anxiety/depression disorders.

The ESS is a validated self administered questionnaire with 8 questions. Respondents rate on a 4-point scale (0 to 3) their chances of dozing off or falling asleep while engaged in 8 different activities. The ESS score is the sum of 8 item scores and can range from 0 to 24 points. Higher scores indicate more daytime sleepiness.

Vital signs included sitting systolic blood pressure (SBP), sitting diastolic blood pressure (DBP).