One-month delay in methotrexate initiation on rheumatoid arthritis outcomes: One-year ancillary analysis of the VACIMRA trial

Objectives The VACIMRA trial demonstrated that delaying methotrexate initiation in rheumatoid arthritis (RA) by one month after the 13-valent pneumococcal conjugate vaccine (PCV13) improves humoral responses at 1 and 12 months. Whether this delay impacts disease activity and radiographic progression over one year remains uncertain. Methods This ancillary study compared changes in disease activity (DAS28-ESR) from inclusion (M0) to months 1, 2, 3, 6, and 12 between patients with early RA who started methotrexate immediately vs one month after PCV13. Structural progression was assessed using the van der Heijde-modified Sharp score (mSHS) on X-rays at inclusion, 6 and 12 months. The primary outcome was the proportion of patients in remission (DAS28-ESR < 2.6) or low disease activity (LDA) (DAS28-ESR ≤ 3.2) at one year. Results Among 276 VACIMRA participants, 100 were enrolled at the Montpellier center (96 analyzable at M0, 83 at M12). Both groups had similar baseline characteristics: mean age 58 ± 14 years, DAS28-ESR 4.88 ± 0.94, total mSHS 1.53 ± 3.62. Treatments during follow-up were comparable except for methotrexate cumulative dose at 1, 3, 6 months. At 12 months, remission (53.7% vs 46.3%, p= 0.51) and LDA rate (75.6% vs 61.0%, p= 0.15) were similar. DAS28-ESR was similar at 1 and 3 months but favored the DELAY group at 6 (2.66 ± 1.07 vs 3.28 ± 1.34, p= 0.02) and 12 months (2.23 ± 1.03 vs 3.00 ± 1.16, p< 0.01). mSHS progression was comparable at 6 and 12 months. Conclusion Deferring methotrexate for one month after PCV13 to enhance immunity did not worsen RA disease control, radiographic progression, or treatment escalation after one year of follow-up.