Background: The introduction of anti-tumor necrosis factor α (anti-TNFα) drugs has improved the clinical outcomes in rheumatoid arthritis (RA) and ankylosing spondylitis (AS). However, these drugs may cause adverse effects that motivate a change in or discontinuation of the treatment.
Objective: To evaluate the causes of discontinuation or changes in the dosage regimen in a cohort of patients with RA and AS treated with infliximab, adalimumab, etanercept, and golimumab under clinical practice conditions.
Methods: This was a retrospective observational study that included patients with RA or AS treated with anti-TNFα drugs between 2008 and 2013. Changes in the dosage regimen, reasons for treatment discontinuation, and adverse effects were recorded and analyzed. Time to discontinuation was estimated using Kaplan-Meier survival analysis.
Results: A total of 123 patients with RA and 93 patients with AS were treated with anti-TNFα therapy. During the study, 55.3% of RA patients and 41.7% of AS patients had stopped the treatment. The most frequent changes were modifications in the dosing, and the most frequent adverse effects were reactions after the infusion or injection (53.8% and 66.7% in RA and AS, respectively). Drug survival of etanercept in RA (67.9%) is greater than for adalimumab and infliximab, whereas drug survival of infliximab in AS (70.0%) is greater than for etanercept and adalimumab at 5 years, although there were no significant differences ( P = 0.098 in RA and 0.194 in AS).
Conclusions: The main cause of discontinuation of anti-TNFα is therapeutic failure in both diseases. Etanercept and infliximab have the best survival rates in RA and AS, respectively.
Keywords: adverse drug reactions; alcohol intoxication; drug utilization; rheumatology; therapeutic monitoring.