Background Previous studies have found that 26 to 34% of Rheumatoid Arthritis (RA) patients using Tumor Necrosis Factor (TNF)-inhibitors discontinue their treatment within one year [1,2]. Infliximab has been associated with poorer drug survival as compared to adalimumab and etanercept.
Objectives The aim of this study was to assess the drug survival on TNF-inhibitors including golimumab and certolizumab pegol among patients with RA and the effect of co-medication on drug survival.
Methods Patients were identified from the National Register for Biologic Treatment in Finland (ROB-FIN), which is a longitudinal cohort study established in 1999 to monitor the effectiveness and safety of Biologic Disease Modifying Anti-Rheumatic Drugs (bDMARDs) in rheumatic diseases. Inclusion was limited to TNF-inhibitor treatments started as the patients' first, second or third biologic treatment between 2004 and 2014. Missing baseline data was imputed by multiple imputation. Follow-up data was available until the end of 2015; however follow-up of individual treatment periods was truncated at 36 months. A Cox proportional hazards model with age as well as conventional synthetic DMARD (csDMARD) and glucocorticoid use as time-dependent confounders was carried out to compare the survival of individual TNF-inhibitors and to study the effect of co-medication. The results were reported as adjusted Hazard Ratios (HRs) with 95% Confidence Intervals (CI).
Results Of the 4,067 TNF-inhibitor treatment periods identified from ROB-FIN, 3,345 periods from 2,641 patients met the inclusion criteria, accumulating a total of 5,620 patient years. Median baseline age and DAS28 score were 55 and 3.8, respectively while 74% of the included patients were women. Etanercept, adalimumab, infliximab, golimumab and certolizumab Pegol were used by 1320 (39%), 1306 (39%), 333 (10%), 195 (5.8%) and 191 (5.7%) patients, respectively.
Infliximab (34%) and golimumab (20%) were associated with the highest and the lowest percentages of patients discontinuing their treatment within one year, respectively while the overall percentage was 23%. Infliximab (HR 2.2, 95% CI 1.6–3.1) and certolizumab pegol (HR 1.8, 95% CI 1.3–2.6) had lower drug survival when compared to golimumab. Similar although statistically non-significant trend was seen with adalimumab (HR 1.3, 95% CI 0.99–1.8) and etanercept (HR 1.4, 95% CI 0.99–1.8) as well. Concomitant use of methotrexate (MTX) with or without any additional csDMARDs was associated with improved drug survival (HR 0.78, 95% CI 0.66–0.92) in comparison with TNF-inhibitor monotherapy.
Conclusions We found that golimumab was better in terms of drug survival than infliximab or certolizumab pegol and at least as good adalimumab and etanercept. Concomitant use of MTX improves drug survival on TNF-inhibitors.
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Acknowledgement This study was sponsored by MSD. In addition, ROB-FIN has received financial support from the following pharmaceutical companies: Abbvie, Pfizer and Roche.
Disclosure of Interest None declared