RT Journal Article
SR Electronic
T1 Evidence for differential acquired drug resistance to anti-tumour necrosis factor agents in rheumatoid arthritis
JF Annals of the Rheumatic Diseases
JO Ann Rheum Dis
FD BMJ Publishing Group Ltd and European League Against Rheumatism
SP 746
OP 752
DO 10.1136/ard.2005.045062
VO 65
IS 6
A1 A Finckh
A1 J F Simard
A1 C Gabay
A1 P-A Guerne
A1 for the SCQM physicians
YR 2006
UL http://ard.bmj.com/content/65/6/746.abstract
AB Background: Acquired drug resistance or gradual drug failure has been described with most disease modifying antirheumatic drugs (DMARDs) and is also starting to be recognised with anti-tumour necrosis factor (anti-TNF) agents.Objective: To study acquired drug resistance to anti-TNF agents in rheumatoid arthritis (RA).Methods: Swiss health authorities requested continuous monitoring of patients receiving biological agents. Intensification of co-therapy with traditional DMARDs, gradual dose escalation, and drug discontinuation rates in all patients receiving infliximab, etanercept, or adalimumab, adjusting for potential confounders, were analysed. Intensification of DMARD co-therapy and time to discontinuation of the three anti-TNF agents were analysed using a proportional hazards models. Dose escalation and evolution of RA disease activity (DAS28) were analysed using a longitudinal regression model.Results: 1198 patients contributing 1450 patient-years of anti-TNF treatment met the inclusion criteria. The rate of intensification of traditional DMARD co-therapy over time was significantly higher with infliximab (hazards ratio = 1.73 (99% confidence interval (CI) 1.19 to 2.51)) than with the two other agents. Infliximab also showed significant dose escalation over time, with an average dose increase of +12% (99% CI 8% to 16%) after 1 year, and +18% (99% CI 11% to 25%) after 2 years. No significant differences in discontinuation rates were seen between the three anti-TNF agents (ANOVA, p = 0.67). Evolution of disease activity over time indicated a lower therapeutic response to infliximab (DAS28, p<0.001) compared with etanercept, after 6 months’ treatment.Conclusions: In this population, infliximab was associated with a higher risk of requiring intensification of DMARD co-therapy than the other anti-TNF agents and a significant dose escalation over time. Analysis of RA disease activity indicated a reduced therapeutic response to infliximab after the first 6 months of treatment, suggestive of acquired drug resistance.