Discontinuation vs. continuation of concomitant methotrexate in patients with rheumatoid arthritis on certolizumab pegol: results from a randomised, controlled trial.

Objective: The present non-inferiority study was designed to compare the effect of discontinuing versus continuing methotrexate (MTX) alongside certolizumab pegol (CZP) on maintaining low disease activity (LDA) in rheumatoid arthritis (RA) patients already stable on combination therapy.

Methods: This multicentre, open-label, randomised, controlled trial included RA patients with sustained LDA (Clinical Disease Activity Index [CDAI] ≤ 10) for ≥ 12 weeks with CZP + MTX. Patients were randomised 1:1 by computer to either continue MTX (CZP + MTX group) or discontinue MTX after a 12-week reduction period (CZP group) using a dynamic allocation strategy with the minimisation method. The primary endpoint was the proportion of patients maintaining LDA without a flare (i.e., a CDAI score > 10 or intervention with rescue treatments for any reason) at week 36 (24 weeks after MTX discontinuation). Non-inferiority is verified if the lower limit of the 90% confidence interval (CI) using normal approximation for the difference in the proportion of cases that maintained LDA at week 36 between the intervention group and control group exceeds the non-inferiority margin.

Results: All 84 screened patients were randomised to the CZP + MTX group (n = 41) and CZP group (n = 43), and were included in the efficacy analysis. Proportions (90% CI) of patients who maintained LDA at week 36 were 85.4% (76.3 to 94.4%) in the CZP + MTX group and 83.7% (74.5 to 93.0%) in the CZP group. The difference (90% CI) between the two groups was - 1.6% (-14.6 to 11.3%), with the lower limit of the 90% CI exceeding the non-inferiority margin of -18%. Reported adverse events were broadly similar between the two groups. The proportion of patients with gastrointestinal symptoms, as assessed by a self-administered questionnaire, was significantly lower in the CZP group than in the CZP + MTX group at week 36 (2.4% vs. 15.8%, P = 0.034).

Conclusion: Discontinuing concomitant MTX in RA patients on CZP is clinically feasible for maintaining LDA.

Trial Registration: Japan Registry of Clinical Trials (jRCTs041200048).