To report results of FLUENT, a Phase IV, 12-month, prospective, multicenter, nonrandomized, open-label study in adult patients with relapsing MS (RMS) receiving fingolimod 0.5mg/day.

The relationships between cell subtype changes in the immune system while on short- and long-term fingolimod therapy, and safety are not fully understood.

Patients were stratified to Cohort 1, fingolimod-naïve and Cohort 2, previously treated with fingolimod 0.5mg/day continuously for ≥2 years. Primary outcome is change from study Baseline to Month 6 in immune cell subtype profile. Secondary outcomes include anti-JC virus (JCV) antibody status and change from Baseline to Months 3 and 12 in immune cell subtype profile, and Months 3, 6, and 12 in anti-JCV antibody index. Change from Baseline to Months 3, 6, and 12 in serum neurofilament levels is an exploratory outcome. Descriptive statistics will be provided (95% confidence intervals calculated for mean values). Adverse event (AE) and serious AE (SAE) incidence will be assessed. This primary analysis will be conducted when patients have completed Month 6 follow-up.

To date, 167 and 217 patients have enrolled into Cohort 1 and 2, respectively. Patient demographics/baseline characteristics will be presented. Mean change from Baseline to Month 6 in CD4+/CD8+ naïve, central, and effector memory T cells; CD4+ T helper (Th)1, Th2, and Th17 cells; CD19+ naïve, memory, and regulatory B cells; CD14+ monocytes; CD16+ neutrophils; and CD56+ natural killer cells will be reported. Anti-JCV antibody index and status, and serum neurofilament outcomes will also be reported. AEs/SAEs will be summarized.

These primary analysis results will specify temporal changes occurring in the immune cell subtype profile in patients with RMS receiving short- or long-term fingolimod therapy, and the relationship between these changes and safety outcomes.