Importance of methotrexate therapy concomitant with tocilizumab treatment in achieving better clinical outcomes for rheumatoid arthritis patients with high disease activity: an observational cohort study.

Objective: The purpose of this study was to identify the effects of concomitant use of MTX and baseline characteristics for remission in the treatment of RA with tocilizumab (TCZ) in daily clinical practice.

Methods: A total of 240 RA patients who received TCZ were selected from the multicentre Tsurumai Biologics Communication Registry. Predictive baseline factors for remission [28-item DAS (DAS28) < 2.6] at 52 weeks were determined by logistic regression analysis. To confirm whether the associations varied by the level of baseline disease activity, we also assessed the model including the interaction term (each baseline variable × DAS28).

Results: In total, 49.3% of the study participants used MTX with TCZ. Even after controlling for the baseline DAS28, shorter disease duration (≤3 year) [odds ratio (OR) 3.58 (95% CI 1.81, 7.07)], less structural damage [Steinbroker stage ≤II, OR 2.33 (95% CI 1.32, 4.12)] and concomitant prednisolone use [OR 0.38 (95% CI 0.21, 0.68)] showed significant predictive values for remission. Concomitant MTX use failed to show a significant association with remission, whereas a significant interaction was observed among concomitant MTX use × DAS28 (P = 0.006). In patients with high baseline disease activity (DAS28 > 5.1), concomitant MTX use was associated with increased odds for remission [adjusted OR for all baseline variables 2.54 (95% CI 1.11, 5.83)], while no association was indicated between them in patients with low to moderate baseline disease activity (DAS28 ≤ 5.1).

Conclusion: Concomitant MTX use is an important component of TCZ treatment for RA patients with high disease activity.