Background Drug survival can be considered as a composite measure of efficacy and safety in clinical practice. Although the drug survival rate of biologic agents in the treatment of rheumatoid arthritis (RA) has recently been extensively studied, only few studies have examined the drug survival rate for tacrolimus (TAC) in such cases.
Objectives The present study aimed to investigate the drug survival rate of TAC in the treatment of RA and to analyse the potential predictors of this rate in routine clinical care.
Methods In this retrospective longitudinal study, we enrolled 102 RA patients treated with TAC for at least 1 year from April 2009 to January 2014 at a tertiary centre in South Korea. The causes of TAC discontinuation were classified as lack of efficacy (LOE), adverse events (AEs), and others (patient or medical decision and miscellaneous). The drug survival rate was estimated using the Kaplan-Meier method and the predictors of this rate were identified by Cox-regression analyses.
Results TAC was discontinued in 27 of 102 RA patients (26.5%), after a mean duration of 34.1 months; the number of TAC discontinuations due to LOE, AEs, and others was 15 (14.7%), 11 (10.8%) and 1 (1%), respectively. The 2-year survival rate for TAC was 78.3% (Figure 1). Multivariable Cox-regression models indicated that compared to RA patients with low or moderate disease activity (Disease Activity Score 28-erythrocyte sedimentation rate [DAS28-ESR] ≤5.1), RA patients with high baseline disease activity had a significantly higher risk of TAC discontinuation, regardless of the cause (HR=2.49; 95% CI=1.16-5.35, p=0.019), or specifically, due to LOE (HR=3.55; 95% CI=1.25-10.09, p=0.02). Moreover, younger age (<60 years) at the start of TAC treatment was marginally associated with worse TAC survival due to LOE (HR=4.46; 95% CI=1.00-19.91, p=0.050).
Conclusions In the present study, RA patients exhibited a good 2-year TAC survival rate of 78.3%. Moreover, a high baseline disease activity was a significant predictor for TAC withdrawal, regardless of the cause, or specifically, due to LOE.
Disclosure of Interest None declared