Differences in biologic dose-escalation, non-biologic and steroid intensification among three anti-TNF agents: evidence from clinical practice.

OBJECTIVES: To evaluate prevalence of dose escalation among RA patients in normal clinical practice treated with etanercept, adalimumab or infliximab and to estimate its economic impact.
METHODS: A retrospective observational study of 739 patients with RA receiving continuous treatment with etanercept (n=319), adalimumab (n=313) or infliximab (n=107) for 18 months. Dose escalation, intensification of concomitant DMARDs and risk of dose escalation were evaluated, as well as costs.
RESULTS: Significantly more patients prescribed adalimumab (10%, p<0.001) or infliximab (35%, p<0.001) experienced dose escalation compared with patients treated with etanercept (3%). DMARD or steroid dose adjustment, when added as criteria of escalation, occurred more often among patients treated with adalimumab (28%; p=0.022) or infliximab (47%; p<0.001) than those prescribed etanercept (19%). Independent of confounding covariates, hazard of dose escalation was significantly higher for either infliximab (28.1-fold) or adalimumab (4.9-fold) relative to etanercept. Escalation among subjects treated with either infliximab or adalimumab incurred statistically significant increases in total cost of care compared with non-escalators whereas such differences observed for subjects treated with etanercept were not significant.
CONCLUSIONS: Patients receiving monoclonal antibody therapies, adalimumab or infliximab, had significantly higher rates of dose escalation than patients receiving the soluble TNF receptor, etanercept, and related costs were higher.