Teriflunomide effect on immune response to influenza vaccine in patients with multiple sclerosis

OBJECTIVE: To investigate the effect of teriflunomide on the efficacy and safety of seasonal influenza vaccine. METHODS: The 2011/2012 seasonal influenza vaccine (containing H1N1, H3N2, and B strains) was administered to patients with relapsing forms of multiple sclerosis (RMS) treated for ≥6 months with teriflunomide 7 mg (n = 41) or 14 mg (n = 41), or interferon-β-1 (IFN-β-1; n = 46). The primary endpoint was the proportion of patients with influenza strain–specific antibody titers ≥40, 28 days postvaccination. RESULTS: More than 90% of patients achieved postvaccination antibody titers ≥40 for H1N1 and B in all groups. For H3N2, titers ≥40 were achieved in ≥90% of patients in the 7 mg and IFN-β-1 groups, and in 77% of the 14-mg group, respectively. A high proportion of patients already had detectable antibodies for each influenza strain at baseline. Geometric mean titer ratios (post/prevaccination) were ≥2.5 for all groups and strains, except for H1N1 in the 14-mg group (2.3). The proportion of patients with a prevaccination titer <40 achieving seroprotection was ≥61% across the 3 treatment groups and 3 influenza strains. However, fewer patients in the 14-mg than the 7-mg or IFN-β-1 groups exhibited seroprotection to H3N2 (61% vs 78% and 82%, respectively). CONCLUSION: Teriflunomide-treated patients generally mounted effective immune responses to seasonal influenza vaccination, consistent with preservation of protective immune responses. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that teriflunomide generally does not adversely impact the ability of patients with RMS to mount immune responses to influenza vaccination.