Background Tocilizumab (TCZ) and anti-tumor necrosis factor (TNF) biologic agents are key therapies in the management of rheumatoid arthritis (RA). They are considered to be equally effective and very few head-to-head comparisons have been published.
Objectives To compare response to therapy in RA patients treated with anti-TNF agents and TCZ according to different response measures and determine the factors influencing it.
Methods We included RA patients registered in the Rheumatic Diseases Portuguese Register, Reuma.pt, who started anti-TNF or TCZ after January 1, 2008, were treated for at least 6 months and had available DAS28 scores at baseline and at 6 months. Our primary outcome was the change in DAS28, CDAI and SDAI at 6 months. We performed linear regressions to compare the groups and determined the best model predicting change in disease activity for each index.
Results 524 RA patients were enrolled, (106 adalimumab, 202 etanercept, 43 golimumab, 78 infliximab, 95 TCZ). At baseline, TCZ users were less frequently naïve to biologic therapies (54.7% vs. 85%, p<0.0001), had more swollen and tender joint counts (p<0.0001 and p=0.02, respectively) and higher disease activity according to all indexes: DAS28 6.1±1.1 vs. 5.4±1.3 (n=524, p<0.0001), CDAI 33.3±13.2 vs. 28.1±13.6 (n=376, p=0.005), SDAI.35.6±13.1 vs. 29.1±30.4 (n=361, p=0.004). At 6 months, change in DAS28, CDAI, SDAI and joint counts was significantly higher in the TCZ group (Table 1). Multivariate linear regression models best predicting change in disease activity included biologic class, number of previous biologics, baseline activity, gender and ACPA/RF status (Table 2). Compared to anti-TNF, TCZ was associated with a larger difference in ΔDAS28, ΔCDAI and ΔSDAI of, respectively, 1.45, 4.25 and 5.41.
Conclusions TCZ treatment was associated with greater change in DAS28, CDAI, SDAI and joint counts at 6 months. Biologic class, number of previous biologics, baseline activity, gender and ACPA/RF status predicted change in disease activity.
Disclosure of Interest None declared