Effect of methotrexate discontinuation on efficacy of seasonal influenza vaccination in patients with rheumatoid arthritis: a randomised clinical trial.

Objective: To investigate whether temporary discontinuation of methotrexate (MTX) improves the efficacy of seasonal influenza vaccination in patients with rheumatoid arthritis (RA).

Methods: In this prospective randomised parallel-group trial, patients with RA taking stable dose of MTX were randomly assigned at a ratio of 1:1:1:1 to continue MTX (group 1), suspend MTX for 4 weeks before vaccination (group 2), suspend MTX for 2 weeks before and 2 weeks after vaccination (group 3) or suspend MTX for 4 weeks after vaccination (group 4). All participants were vaccinated with trivalent influenza vaccine containing H1N1, H3N2 and B-Yamagata. The primary outcome was frequency of satisfactory vaccine response (≥4-fold titre increase 4 weeks postvaccination). Secondary endpoints included fold change in antibody titres from baseline.

Results: The per-protocol population consisted of 199 patients (n=54, 44, 49 and 52 in groups 1, 2, 3 and 4, respectively). Group 3 achieved higher satisfactory vaccine response against all three antigens than group 1 (51.0% vs 31.5%, p=0.044). The anti-H3N2 antibody fold increase (95% CI) was significantly higher in groups 3 and 4 (12.2 (8.4 to 17.5), p <0.001 and 10.0 (6.8 to 14.8), p=0.043, respectively) than group 1 (5.9 (4.3 to 8.1)). The anti-B-Yamagata antibody responses of groups 3 and 4 were higher (4.7 (3.3 to 6.7), p=0.048; 6.1 (4.2 to 8.8), p <0.001, respectively) than group 1 (2.9 (2.2 to 3.8)). RA flare occurred in 24.1%, 21.2%, 34.1% and 38.8% in groups 1, 2, 3 and 4, respectively (p=NS).

Conclusions: Temporary MTX discontinuation improves the immunogenicity of seasonal influenza vaccination in patients with RA.

Trial Registration: Trial registration number is: www.clinicaltrials.gov, NCT02748785.