AB0416 Which factors predict the responsiveness to tocilizumab in rheumatoid arthritis? the difference between the usage as the first biologic and as the second biologic
Authors: Y Kunishita, R Yoshimi, H Nagai, N Hamada, Y Soejima, Y Sugiyama, N Tsuchida, H Nakano, D Kishimoto, R Kamiyama, Y Asami, Y Kirino, H Nakajima
Journal: Annals of the Rheumatic Diseases (2017)

<h3>Background</h3> Although recent development of a variety of biologics has dramatically improved treatment for rheumatoid arthritis (RA), it is still unclear which biologics is better for use in each patient. Some previous studies have shown the predictive factors for good response (GR) to tocilizumab (TCZ), including low HAQ, high DAS28<sup>1)</sup>, low levels of serum soluble IL-6 receptor<sup>2)</sup>, and low numbers of previous use of other biologics<sup>3)</sup>. However, the consensus is not immediately available. <h3>Objectives</h3> To compare continuation rates (CR) of TCZ by the responsiveness to the therapy and to identify predictive factors for GR to TCZ in RA. <h3>Methods</h3> Patient with RA who newly started receiving TCZ after April 2008 in our hospital, were included in the study. We collected patient records, medication histories, laboratory data, and clinical parameters longitudinally after starting TCZ. Statistical analyses were performed using the chi-square test, binomial <i>logistic regression</i> analysis, Kaplan-Meier method, and the log-rank test. <h3>Results</h3> Ninety-two patients were included in the study. The mean age and disease duration at baseline were 60.0±13.5 years and 8.7±8.0 years, respectively. The seroprevalence of the anti-cyclic citrullinated peptide antibody and the rheumatoid factor were 95.4% and 95.7%, respectively. The rate of methotrexate and prednisolone at baseline were 45.7% and 64.1%, respectively. TCZ was administered as the first biologic in 42 patients, and as the second biologic in 33. DAS28(ESR) and CDAI revealed high disease activity at baseline (5.2±1.5 and 25.4±14.1, respectively). The mean CR of all patients was 42.1±4.0 months. The CR was significantly higher in patients who achieved GR in EULAR response criteria at 6 months after starting TCZ than those who did not achieve GR (54.0±6.0 months vs 29.0±5.3 months, <i>p</i>=0.004). Multivariate statistical analysis revealed two predictive factors for achieving GR at 6 months after starting TCZ, the low number of previous use of other biologics and the low CDAI at baseline (<i>p</i>=0.018, odds ratio (OR) =0.386, and <i>p</i>=0.011, OR=0.944, respectively). We divided the patients into two groups, patients using TCZ as the first biologic and patients using it as the second biologic. Univariate statistical analyses revealed low usage rate and dose of prednisolone (PSL) and low serum creatinine level at baseline as the predictive factors for achieving GR in patients using TCZ as the first biologic, and low DAS28(ESR), CDAI and HAQ-DI in the patients using TCZ as the second biologic. By multivariate statistical analysis, we identified the low CDAI as a predictive factor in the patients using TCZ as the second biologic. <h3>Conclusions</h3> RA patients who achieved GR at 6 months after starting TCZ showed higher CR than the others. This study also suggests that low number of biologics usage and low CDAI at baseline are the predictive factors for GR. The history of biologics usage may be important to identify the predictive factors for GR to TCZ. <h3>References</h3> Ann Rheum Dis 2011;70:1216–22. Ann Rheum Dis 2014;73:945–7. Pharmacological Research 2016;111:264–71. <h3>Disclosure of Interest</h3> None declared