One-month delay in MTX initiation on RA outcomes: 1-year ancillary analysis of the VACIMRA trial

The VACIMRA trial demonstrated that delaying MTX initiation in RA by 1 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 1 year remains uncertain.

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 MTX immediately vs 1 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 1 year.

Among 276 VACIMRA participants, 100 were enrolled at the Montpellier centre (96 analysable 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 MTX 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 favoured 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.

Deferring MTX for 1 month after PCV13 to enhance immunity did not worsen RA disease control, radiographic progression or treatment escalation after 1 year of follow-up.