Previous studies reported that anti-CCP antibody positivity predicts good response to rituximab (RTX) in rheumatoid arthritis (RA). A quantitative approach to such possibility could be a good way to detect the subset of patients most likely to respond. We investigated whether serum anti-CCP antibody titres could predict response to RTX in RA patients.
We retrospectively investigated RA patients who received RTX. The primary criterion was decrease in DAS28>1.2 at 6months (M6). Secondary efficacy criteria included a good response and remission according to EULAR. Predictors of response were investigated by multivariate logistic regression analysis.
We included 114 RA patients (81.6% female, median age 53.5 [IQR 45.7-61.2] years, median disease duration 8.5 [4.0-16.0] years). Anti-CCP antibodies were present in 93 patients (81.6%), with median anti-CCP antibody titres 583 [195-1509] U/mL. In all, 44 patients (38.6%) showed decreased DAS28>1.2 at M6. On univariate analysis, high anti-CCP titres were associated with response rather than non-response to RTX (median 1122 [355-1755] vs. 386 [149-800] U/mL, P=0.0191) at M6. On multivariate regression analysis, with a cut-off of 1000 U/mL, anti-CCP antibody titres≥1000 was associated with a decrease in DAS28>1.2 (OR 5.10 [1.97-13.2], P=0.0002); a EULAR good response (4.26 [1.52-11.95], P=0.0059); and a trend for EULAR remission (2.52 [0.78-8.12], P=0.1207).
High anti-CCP antibody titres predict response to RTX in RA. This factor, easily assessed in clinical practice, can help with personalized medicine and selecting the best candidates for RTX treatment.