Background Biologics (Bio) therapy has become a standard therapy in the treatment of rheumatoid arthritis (RA) and long-term outcomes can be evaluated recently. Although one of the desirable treatment strategy is to stop Bio therapy after reaching targets to treat such as remission or low disease activity (Bio-free), other desirable treatment strategy is to continue Bio therapy and to sustain targets to treat. Several studies showed it difficult to continue Bio-free for a long time, so it is a practical strategy to continue Bio therapy in clinical setting.
Objectives This observational cohort study investigated the treatment retention rate of Bio therapy and the predictors of its continuation in patients with RA.
Methods 254 RA patients who initiated any of biologic agents (infliximab, etanercept, adalimumab, tocilizumab, abatacept, golimumab) as first Bio in our institute from 2003 to 2013 were included in this study. Switching from one Bio agent to another was defined as continuation of Bio therapy in this study. Patients' characteristics and treatment retention rate were investigated. The outcomes at last observation in both the Bio-continued and the Bio-stopped were compared with each other. Bio-free due to remission and stopping Bio therapy related to pregnancy were assigned to the Bio-continued. The predictors for continuation of the Bio therapy were also investigated.
Results Baseline characteristics was as follows. % female was 82.7%. Mean age was 57.8 years old. Mean RA duration was 11.3 years. % methotrexate (MTX) concomitant was 81.5% and mean used dose was 8.5mg/weeks (MTX dose was restricted up to 8mg/weeks until 2011 in Japan and 16mg/w after 2011). % prednisolone (PSL) concomitant was 56.3%. % Bio monotherapy was 13.6%. Mean baseline DAS28-CRP and SDAI was 4.74 and 25.8, respectively. % high disease activity measured using DAS28 and SDAI at baseline was 41.7% and 46.3%, respectively. Baseline disease activity were getting lower year by year. Treatment continuation rates using Kaplan-Meier method were 88.4% at 1 year, 82.1% at 3 years, 74.4% at 5 years and 70.4% at 7 years. Reasons for stopping Bio therapy were infection at first, hope of patients or absent to hospital at second and worsened comorbidities at third. Lower disease activity and more remission rates were observed in the Bio- continued compared with the Bio-stopped. Predictors of continuation of Bio therapy were shorter RA duration, fewer concomitant prednisolone, more concomitant MTX, lower disease activity, good renal function, fewer lung disease and glucose intolerance in univariate analysis. Concomitant MTX, heavy body weight and glucose tolerance (defined as patients with abnormal HbA1c or treated with drugs for diabetes mellitus) was detected as predictors of continuation of Bio therapy in multivariate analysis.
Conclusions Our cohort study showed that long-term continuation rate of Bio therapy was about 60-70% in 7-8 years. Infection was the most reasons for stopping Bio therapy. Baseline characteristics of RA patients who initiated Bio therapy were one of the important predictors for continuation of Bio. Comorbidities were one of the important influencers on treatment retention rate of Bio therapy and glucose intolerance was the most important influencer in this study.
Disclosure of Interest Y. Hirano Speakers bureau: Abbott Japan Co. Ltd.; Eisai Co. Ltd.; Mitsubishi Tanabe Pharma Corporation; Pfizer Co. Ltd.; Chugai Pharmaceutical Co. Ltd.; and Bristol-Myers Squibb Co. Ltd., S. Hirabara: None declared, M. Isono: None declared, Y. Oishi: None declared, T. Kojima Speakers bureau: Abbott Japan Co. Ltd.; Eisai Co. Ltd.; Mitsubishi Tanabe Pharma Corporation; Pfizer Co. Ltd.; Chugai Pharmaceutical Co. Ltd.; and Bristol-Myers Squibb Co. Ltd., N. Ishiguro Speakers bureau: Abbott Japan Co. Ltd.; Eisai Co. Ltd.; Mitsubishi Tanabe Pharma Corporation; Pfizer Co. Ltd.; Chugai Pharmaceutical Co. Ltd.; and Bristol-Myers Squibb Co. Ltd.