To compare retention of tocilizumab (TCZ) as monotherapy vs combination therapy with MTX in RA patients achieving clinical improvements during the first year.
We performed a multicentre cohort study using a real-life registry containing RA patients who had begun TCZ with or without MTX between April 2008 and November 2016. Among patients with ≥50% improvement of clinical disease activity index (CDAI) during the first year (CDAI50 responders), we evaluated whether MTX use may have affected TCZ discontinuation during the second and subsequent years (maintenance therapy).
Among 510 patients with high or moderate CDAI, 328 (64.3%) were CDAI50 responders. The rate of MTX use was 53.0% among responders and 54.4% among non-responders. During maintenance therapy (mean follow-up 30.7 months), 43.9% of CDAI50 responders discontinued TCZ. The most common cause was efficacy loss followed by adverse events. Kaplan-Meier estimates for TCZ retention were 48.3 months (95% CI 42.0, 54.5) for monotherapy and 50.0 months (95% CI 45.9, 54.0) for combination therapy. According to Gray's test, there was no significant impact of MTX use on cumulative incidence of efficacy loss or adverse events. In the Fine-Gray competing risk regression model, CDAI >10 at the start of maintenance therapy and age were predictive factors for TCZ discontinuation due to efficacy loss (hazard ratio 2.58, 95% CI 1.41, 4.72) and adverse events (hazard ratio 1.04, 95% CI 1.01, 1.08), respectively.
There was no significant difference in TCZ retention between monotherapy and combination therapy with MTX.