Assessing retention rate and risk factor for drug discontinuation is important for drug evaluation. We examined a 3-year retention rate and the risk factor for discontinuation due to insufficient efficacy (IE) and adverse events (AE) in Japanese patients with rheumatoid arthritis (RA) who are receiving etanercept (ETN).
Data were collected from 588 patients treated with ETN as a first biologic from the Tsurumai Biologics Communication Registry. Baseline characteristics for the incidence of both IE and AE were analyzed using the Cox proportional-hazards regression model. Patients were divided into groups based on age and concomitant methotrexate (MTX). Drug retention rates were calculated using the Kaplan-Meier method and compared among groups using the log-rank test.
ETN monotherapy without concomitant MTX [MTX(-)] was significantly related to a higher incidence of discontinuation due to IE [hazard ratio (HR) = 2.226, 95% CI 1.363-3.634]. Older age and MTX(-) were significantly related to a higher incidence of discontinuation due to AE [HR = 1.040, 1.746, 95% CI 1.020-1.060, 1.103-2.763, respectively]. The MTX(-)/≥ 65 years group had the lowest retention rate (p < 0.001). The discontinuation rate due to IE was lower in the MTX(+)/< 65 years group compared to < 65 years/MTX(-), ≥ 65 years/MTX(-) group (p = 0.006, p < 0.001, respectively). The discontinuation rate due to AE was highest in the MTX(-)/≥ 65 years group (p < 0.001).
Our findings suggest that the risk of discontinuation due to IE was high in the patients who did not use concomitant MTX and that the risk of discontinuation due to AE was high in elderly patients who did not use concomitant MTX.