This study will determine whether in RRMS patients receiving Gilenya there is a link between disease progression and biologic markers.

The biologic basis that determines disease progression in multiple sclerosis (MS) patients remains to be defined. We propose that a long term study of patients where inflammatory activity of the disease is expected to be controlled on treatment, will identify patients into cohorts of those whose disease is deemed to be stable with those patients whose disease has been deemed to progress. Once the two groups have been identified, it will then be possible to assess whether there are differences in biologic markers between the two groups. These markers would then have the potential to be used to monitor disease progression or be predictors for patient response to drug treatment.

Inclusion Criteria:

• Deemed by the subject's treating physician to be a suitable candidate for Gilenya therapy in accordance with the Canadian Product Monograph for Gilenya
• has an overall EDSS not above 7.0
• is not currently receiving Gilenya
• is able to perform adequately for EDSS assessment and cognitive tests
• is able to undergo a MRI
• is able to provide blood samples

Exclusion Criteria:

• is over 65 years of age and under 18 years of age
• has less than 4 weeks of discontinuation with steroid treatment for a relapse.

Patients with relapsing-remitting multiple sclerosis deemed by their treating physician to be a suitable candidate for Gilenya therapy