Time to first clinical relapse was defined as the duration (in weeks) between randomization and first confirmed clinical relapse. Clinical relapses were defined as new or recurrent neurological symptoms not associated with fever or infection, lasting at least 24 hours, and accompanied by new objective neurological findings upon neurological examination and documented by a standardized, quantified functional system score (FSSs) which included 8 items and items were rated on different scales: brain stem, cerebellar and cerebral functions rated on a scale of 0 to 5; visual, pyramidal, sensory and bowel/bladder rated on a scale of 0 to 6 and ambulation on a scale of 0 to 12, where higher score in each scale indicated worsened neurological function. Confirmed clinical relapse were reviewed and confirmed by an independent Relapse Adjudication Panel (RAP). A participant without confirmed clinical relapse, was considered as clinical relapse free until the end of Week 96.

ARR is obtained from the total number of confirmed relapses that occurred during the treatment period divided by the sum of treatment durations. Each episode of relapse - appearance, or worsening of a clinical symptom that was stable for at least 30 days, that persisted for a minimum of 24 hours in the absence of fever - was to be confirmed by an increase in Expanded Disability Status Scale (EDSS) score or Functional System scores. To account for the different treatment durations among participants, a Poisson regression model with robust error variance was used (total number of confirmed relapses as response variable; log-transformed treatment duration as "offset" variable; treatment group, region of enrollment and baseline EDSS stratum as covariates).

Conversion to CDMS was defined by the occurrence of a relapse, which was defined as a new neurological abnormality separated by at least 30 days from onset of a preceding clinical event, presented for at least 24 hours and occurred in the absence of fever or known infection. Percent probability of conversion at 24, 48, and 108 weeks was estimated using Kaplan-Meier method.

Adverse event (AE) was defined as any untoward medical occurrence in a participant who received investigational medicinal product (IMP) without regard to possibility of causal relationship with this treatment. TEAEs: AEs that developed or worsened or became serious during on-treatment period which was defined as the period from the time of first dose of study drug (in LTS6050) up to 4 weeks (28 days) after last dose of study drug. Serious adverse event (SAE) was defined as any untoward medical occurrence that resulted in any of the following outcomes: death, life-threatening, required initial or prolonged in-patient hospitalization, persistent or significant disability/incapacity, congenital anomaly/birth defect, or considered as medically important event. Any TEAE included both serious and non-serious AEs.

ARR is obtained from the total number of confirmed relapses that occured during the treatment period divided by the sum of the treatment durations. Each episode of relapse - appearance, or worsening of a clinical symptom that was stable for at least 30 days, that persisted for a minimum of 24 hours in the absence of fever - was to be confirmed by an increase in EDSS score or Functional System scores. To account for the different treatment durations among participants, a Poisson regression model with robust error variance was used (total number of confirmed relapses as response variable; log-transformed treatment duration as "offset" variable; treatment group, region of enrollment and baseline EDSS stratum as covariates).

For each viral strain (H1N1, H3N2, and B), the antibody titer, level of antibodies in blood sample when exposed to antigen, was calculated as the mean of two replicates. If the titer was below or above the limit of detection, the threshold value was used. The percentage of participants achieving a titer of 40 or more, as well as the 90% confidence interval (CI) using normal approximation were calculated for each strain and treatment group.

AE are any unfavorable and unintended sign, symptom, syndrome, or illness observed by the investigator or reported by the participant during the study.

AE with potential risk of occurrence were defined as follows: * Hepatic disorders; * Immune effects, mainly effects on bone marrow and infection; * Pancreatic disorders; * Malignancy; * Skin disorders, mainly hair loss and hair thinning; * Pulmonary disorders; * Hypertension; * Peripheral neuropathy; * Psychiatric disorders; * Hypersensitivity.

PCSA values are abnormal values considered medically important by the Sponsor according to predefined criteria based on literature review. Hepatic parameters thresholds were defined as follows: * Alanine Aminotransferase \[ALT\] \>3, 5, 10 or 20 Upper Normal Limit \[ULN\]; * Aspartate aminotransferase \[AST\] \>3, 5, 10 or 20 ULN; * Alkaline Phosphatase \>1.5 ULN; * Total Bilirubin \[TB\] \>1.5 or 2 ULN; * ALT \>3 ULN and TB \>2 ULN;

AE with potential risk of occurrence were defined as follows: * Hepatic disorders; * Immune effects, mainly effects on bone marrow and infection; * Pancreatic disorders; * Malignancy; * Skin disorders, mainly Hair loss and Hair thinning; * Pulmonary disorders; * Hypertension; * Peripheral neuropathy; * Psychiatric disorders; * Hypersensitivity.

PCSA values are abnormal values considered medically important by the Sponsor according to predefined criteria based on literature review. Hepatic parameters thresholds were defined as follows: * Alanine Aminotransferase \[ALT\] \>3, 5, 10 or 20 Upper Normal Limit \[ULN\]; * Aspartate aminotransferase \[AST\] \>3, 5, 10 or 20 ULN; * Alkaline Phosphatase \>1.5 ULN; * Total Bilirubin \[TB\] \>1.5 or 2 ULN; * ALT \>3 ULN and TB \>2 ULN;

AE are any unfavorable and unintended sign, symptom, syndrome, or illness observed by the investigator or reported by the participant during the study.

The number of unique active lesions per scan was calculated by dividing the sum of unique newly active lesions and unique persistently active lesions observed on treatment by the number of scans performed on treatment. Unique newly active lesions were all unique T1 and T2 lesions identified, one or more times, in a scan but not in the previous scan and, that had not been classified as unique newly active in any previous scan. Unique persistently active lesions were all unique T1 and T2 lesions identified, one or more times, in a scan and also in the previous scan.