Rheumatoid factor positivity rather than anti-CCP positivity, a lower disability and a lower number of anti-TNF agents failed are associated with response to rituximab in rheumatoid arthritis.

Objectives: We explored clinical factors associated with a major response to rituximab (RTX) (e.g. ACR >/=50, and European League against Rheumatism (EULAR) moderate to good response) in patients with active long-standing RA and inadequate response to anti-TNF agents or traditional DMARDs.

Methods: RTX was used in 110 RA patients in six different Italian centres. The mean disease activity score on 28 joints (DAS28) was 6.4 +/- 0.99 and the mean HAQ was 1.63 +/- 0.68 at baseline. Thirty-two patients (29.1%) underwent RTX after the failure of DMARD therapy, 37 (33.6%) had failed or were intolerant to at least two anti-TNF agents, and 41 (37.3%) had failed or were intolerant to one anti-TNF agent. Univariate and multivariate analyses were performed.

Results: The number of previous anti-TNF agents (P = 0.043), HAQ (P = 0.023), RF positivity (P < 0.0001) and anti-cyclic citrullinated peptide (anti-CCP) positivity (P = 0.003) were associated with ACR response >or=50 between month +4 and month +6 after starting RTX by univariate analysis. Multivariate analysis confirmed that a lower HAQ, a lower number of anti-TNF agents failed before RTX and RF positivity, but not anti-CCP positivity, were the selected variables associated with an ACR response >or=50, with an accuracy of 84% of the model. Only RF positivity correlated with EULAR moderate to good response both in the univariate and in the multivariate analysis, with an accuracy of 79% of the model.

Conclusion: RF-positive rather than anti-CCP-positive RA patients with lower baseline disability and a lower number of previously failed TNF blockers may be the best candidates to RTX.