Treatment Patterns of Biologic Disease-Modifying Antirheumatic Drugs and Janus Kinase Inhibitors in Patients with Rheumatoid Arthritis in Japan: A Claims-Based Cohort Study

Abstract

Background: Reports on treatment patterns of biologic disease-modifying antirheumatic drugs (bDMARDs)/Janus kinase inhibitors (JAKi) for rheumatoid arthritis (RA) in clinical practice are still sparse in Japan, especially in combination with conventional synthetic DMARDs (csDMARDs).

Objectives: The aim of this study was to investigate treatment patterns of bDMARD/JAKi in the treatment of RA in real-world clinical practice in Japan.

Method: A retrospective cohort study was conducted using the Japanese Medical Data Vision health claims database. The inclusion criteria required a recorded diagnosis of RA, defined by ICD-10 codes, in patients aged 18 years and older on the index date. We analyzed 39,903 RA patients treated with DMARDs from 2008 to 2020.

Results: Among analyzed subjects, 10,196 patients (25.6%) were prescribed bDMARDs/JAKi in combination with csDMARDs, and 3067 patients (7.7%) were prescribed these drugs without csDMARDs. Among the bDMARDs/JAKi, tumor necrosis factor inhibitors (TNFi) were the most commonly prescribed DMARD overall, and also the most common first-line therapy, accounting for 60.0% or 45.5% of patients prescribed these drugs in combination with or without csDMARDs, respectively. Switching, temporary discontinuation (restarting with the same agents), and discontinuation of bDMARDs/JAKi were observed in 3150 (30.9%), 1379 (13.5%), and 2025 (19.9%) patients with csDMARDs, and in 849 (27.7%), 513 (16.7%), and 833 (27.2%) patients without csDMARDs, respectively.

Conclusions: Real-world treatment trajectories of bDMARDs/JAKi with and without csDMARDs was analyzed in RA patients in Japan between 2008 and 2020. TNFi were the predominant first-line therapy, and likely to be switched to different classes. Understanding the current treatment patterns, including discontinuation, is important to find an optimal treatment strategy for RA patients.

Fig. 1

Change in the proportion of patients prescribed bDMARDs/JAKi during the period from 2008 to 2020. Data are shown as the percentage of patients prescribed bDMARDs/JAKi, relative to all patients prescribed DMARDs in that year. Of note, the count decreased in 2020 because of a short evaluation period that year. bDMARDs biologic disease-modifying antirheumatic drugs, CTLA4-Ig cytotoxic T lymphocyte-associated antigen-4 immunoglobulin fusion proteins, IL-6i interleukin-6 inhibitor, JAKi Janus kinase inhibitor, TNFi tumor necrosis factor inhibitor

Fig. 2

Proportion of the prescribed bDMARDs/JAKi as a first- to third-line therapy used during 2008 to 2020. bDMARDs biologic disease-modifying antirheumatic drugs, csDMARD conventional synthetic disease-modifying antirheumatic drug, CTLA4-Ig cytotoxic T lymphocyte-associated antigen-4 immunoglobulin fusion proteins, IL-6i interleukin-6 inhibitor, JAKi Janus kinase inhibitor, TNFi tumor necrosis factor inhibitor

Fig. 3

Sankey diagrams showing the switching of first-line bDMARDs/JAKi to second and third line during 2008 to 2020. bDMARDs biologic disease-modifying antirheumatic drugs, csDMARD conventional synthetic disease-modifying antirheumatic drug, CTLA4-Ig cytotoxic T lymphocyte-associated antigen-4 immunoglobulin fusion proteins, IL-6i interleukin-6 inhibitor, JAKi Janus kinase inhibitor, TNFi tumor necrosis factor inhibitor