Background Now, predictive factors at baseline for the good outcome of treatment with biologics are very important not to waste time to treatment goal “remission”.
Objectives The aims of this study are to clarify the characteristics of the patients enrolled in this observational cohort and to identify the predictive factors at baseline for achievement of the remission in treatment with tocilizumab (TCZ), in daily practice setting with background of limited dose of MTX (<8mg/week).
Methods This study included 240 RA patients who received TCZ in the multicenter study group (Tsurumai Biologics Communication Registry; TBCR, 2176 cases treated with biologics were registered until 2011). We explored the differences in baseline characteristics by concomitant use of MTX and by achievement of remission. We also determined the predictive baseline factors for DAS28-ESR remission at week 52 using multivariate logistic regression analysis. Cases in which TCZ therapy was discontinued before 52 weeks were not excluded but rather categorized as “non-responder” for treatment (non-responder imputation).
Results Baseline characteristics: mean (SD); Age 57.9 (13.2) ys, Disease duration 10.2 (8.3) ys, DAS28-ESR 5.6 (1.3), concomitant PSL 67.5%, concomitant MTX 48.8%, mean dose of 7.6 mg/week (In Japan, dose of MTX is limited up to 8mg/week until 2011), previous use of biologics 67.9%. Remission rate (DAS28-ESR) at 52 weeks was 42.9%. We found that DAS28-ESR was significantly lower in patients with concomitant MTX. In the high disease activity group, patients who achieved remission had significantly higher rates of concomitant MTX, less progressive Steinbrocker stages, but not the proportion of patients with previous use of biologics while, in patients with the moderate/low disease activity group (DAS28-ESR ≤5.1), we found no significant differences in baseline characteristics. The multivariable logistic regression analysis showed predictive factors for remission in patients with high disease activity (DAS28 >5.1) at week 52 were follows: concomitant MTX [OR 2.63 (1.16-6.29)] and less structural damage (Steinbrocker stage I+II)[OR 1.44 (1.55-9.69)]. Interestingly, no significant baseline factors were found in the patients with moderate/low disease activity (DAS28 ≤5.1). However, changes in disease activity and its component showed that patients with moderate/low disease activity and those who did not achieve remission showed no remarkable improvement in patient general assessment (VAS) and tender joint count (Fig. 1B), compared to patients who had high disease activity and who did not achieve remission (Fig. 1A) Thus, structural damage could be more influential towards disease activity than inflammation in patients with moderate/low disease activity and those who did not achieve remission.
Conclusions Even low dose of MTX could plays critical roles on RA treatment during TCZ treatment for the patients with high disease activity. The information with background of limited dose of MTX should be important for clinical practice.We should consider structural damage more carefully when the patients with moderate/low disease activity as well as with high disease activity were treated with TCZ to be achieved remission.
Disclosure of Interest T. Kojima Speakers bureau: Mitsubishi Tanabe Pharma Corporation, Takeda Pharma Corporation, Eisai Pharma Corporation, Chugai Pharma Corporation, Abbott, Bristol-Myers Squibb and Pfizer, N. Takahashi: None declared, K. Funahashi: None declared, S. Asai: None declared, S. Hirabara: None declared, M. Hanabayashi: None declared, Y. Yoshioka: None declared, Y. Yabe: None declared, N. Ishiguro Speakers bureau: Mitsubishi Tanabe Pharma Corporation, Takeda Pharma Corporation, Eisai Pharma Corporation, Chugai Pharma Corporation, Abbott, Bristol-Myers Squibb and Pfizer