Discontinuation rates of biologics in patients with rheumatoid arthritis: are TNF inhibitors different from non-TNF inhibitors?

OBJECTIVE To compare discontinuation rates of first and second biologics in rheumatoid arthritis (RA) by tumour-necrosis factor inhibitor (TNFi) status and identify predictors and reasons for discontinuation. METHODS From 1998 to 2011, self-reported medication use for RA was assessed every 6 months via questionnaire in a longitudinal study in the USA. Time-on-drug analyses were conducted for individual biologics and groups, and annual rates reported. Time to discontinuation of TNFi and non-TNFi was compared, unadjusted and adjusted using propensity score analyses. Baseline and time-varying predictors of biologic discontinuation were derived through Cox regression. RESULTS Of 2281 patients initiating their first biologic, 1100 (48%) discontinued and of 1097 initiating a second biologic, 537 (49%) discontinued. The annual discontinuation rate was 17% (median 4 years) for first biologic and 20% (median 3.3 years) for second biologic. TNFi had lower discontinuation rates than non-TNFi after propensity score adjustment: HR for first biologic 0.49 (0.34 to 0.71) and 0.68 (0.51 to 0.90) for second biologic. The annual discontinuation rate was significantly lower in patients starting their first biologic before January 2005 vs after (16 vs 25%, p=0.005). Predictors of discontinuation for the first biologic included smoking, higher comorbidity index, worse overall health and not using concomitant methotrexate. CONCLUSIONS In this large cohort, patients with RA tended to remain on their first and second biologics for relatively long periods suggesting the drugs' effectiveness. Discontinuation rates were lower in patients using TNFi, and all rates increased after January 2005 when the number of biologics available increased.