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.