New classification/remission criteria have been proposed to ensure the early diagnosis of rheumatoid arthritis (RA) and achieve remission or low disease activity according to strict criteria. As tocilizumab (TCZ) decreases the levels of acute phase proteins (e.g., CRP and ESR), it has been questioned whether it is appropriate to evaluate disease activity in patients on TCZ based on levels of acute phase proteins. In Japan, TCZ was approved in April 2008 as the third biological agent for the treatment of RA. The Michinoku Tocilizumab Study Group (MTSG) has registered RA patients receiving TCZ in 34 institutions in 6 prefectures in Tohoku area to analyze their clinical data. The usefulness of the new ACR/EULAR RA remission criteria (i.e., tender or swollen joint count (SJC/TJC) <1, patient global assessment <1, and CRP of <1 mg/dL; referred to as Criteria A) and Criteria A without CRP (Criteria B) was evaluated in patients receiving TCZ. Also, the association between these criteria and the conventional remission criteria (DAS28-ESR <2.6) was evaluated.
Patients with RA who were registered by the MTSG from May 2008 to November 2009 and received TCZ for 12 months were evaluated. Patients were assessed every 3 months by Criteria A and B and DAS-ESR, and the percentages of patients with remission at month 12 were obtained. The ROC analysis was performed to obtain cut-off values of DAS28-ESR score to achieve remissions according to the new criteria. Data were analyzed using the LOCF method.
TCZ treatment was continued for 12 months in 81.8% of the patients registered by the MTSG. The data of 285 patients were analyzed in this study. The mean age at baseline was 59.6 years; 225 patients (79%) were female and the mean duration of RA was 10.2 years. Other biological agents had been used in 140 patients (49.1%), and methotrexate was used with TCZ in 145 patients (50.9%). At month 12, 71 (24.9%) and 72 (25.3%) patients achieved remission with Criteria A and B, respectively, and no significant difference was observed in the criteria with and without CRP (P=0.9230). Remission with DAS28-ESR was achieved in 164 patients (57.5%). RCO analysis revealed that the cut-off value to expect the achievement of remission with Criteria A was a DAS2-ESR score of <1.54 with sensitivity, specificity, positive predictive value and negative predictive value of 88.7, 85.5%, 67.0% and 95.8%, respectively. However, patients having RA for ³10 years and patients in Stage 4 tended not to achieve remission even if the DAS2-ESR was <1.54.
In the clinical setting, the new remission criteria could confirm the remission with TCZ treatment without being affected by CRP level. The fact that the cut-off value to expect the remission according to the new criteria was DAS28-ESR <1.54 indicated that more stringent remission than the conventional criteria may be required for the new criteria in patients receiving TCZ.
Expectation of achievement of the new criteria of remission with a cut-off level of DAS28-ESR<1.54
Positive predictive rate
Negative predictive rate
Disclosure: T. Ishii, Chugai, 8, Pfizer Inc, 8, Bristol-Myers Squibb, 8, Abbott Immunology Pharmaceuticals, 8 ; Y. Hirabayashi, Chugai, 8 .