Treatment response to a second or third TNF-inhibitor in RA: results from the South Swedish Arthritis Treatment Group Register.

OBJECTIVES: To study treatment response rates of RA patients undergoing second- and third-line anti-TNF therapy and to identify baseline predictors of response to second-line treatment.
METHODS: RA patients monitored in a prospective, observational study, having switched anti-TNF therapy once (first-time switchers, n = 337) or twice (second-time switchers, n = 36)--i.e. following failures with one antibody- and one receptor-type agent--between March 1999 and December 2006, were studied. Treatment responses at 3 months were assessed by the ACR and European League Against Rheumatism (EULAR) response criteria. Predictive potentials for response to second-line treatment of demographics, baseline disease activity measures, disease and treatment characteristics were analysed using logistic regression.
RESULTS: ACR20 response was met by 51% of first-time and 35% of second-time switchers. Corresponding ACR50 rates were 27 and 18%; EULAR overall rates (EULAR good or moderate response) 71 and 58%; EULAR good rates 25 and 9% and 28-joint disease activity score (DAS28) remission rates 16 and 6%. Identified baseline predictors of response to second-line treatment were lower age and HAQ scores, elevated DAS28 values and having ceased the former anti-TNF treatment due to adverse events rather than inefficacy. No variable was predictive for all examined response criteria.
CONCLUSIONS: Response rates of first-time anti-TNF switchers are somewhat below those of anti-TNF naïve RA patients, while the markedly inferior response rates of second-time switchers suggest other therapeutic options to be considered in this situation. Identified baseline predictors of response may be useful indicators to second-line anti-TNF therapy, but vary depending on the response criteria set studied.