Cost per patient-year in response using a claims-based algorithm for the 2 years following biologic initiation in patients with rheumatoid arthritis.

OBJECTIVE: To estimate cost per patient-year in response during 2 years following biologic initiation among patients with rheumatoid arthritis (RA).

METHODS: Adults newly initiating biologics for RA (etanercept, abatacept, adalimumab, certolizumab, golimumab, or infliximab) between January 2009 and July 2011 were identified in the MarketScan Commercial Database. Eligible patients were continuously enrolled 6 months before (pre-index) and 24 months after (post-index) their first (index) biologic claim. Biologic effectiveness was assessed using six criteria during 2-year follow-up: treatment adherence ≥80%, no biologic dose escalation, no biologic switch, no new disease-modifying anti-rheumatic drug, no new/increased glucocorticoid dose, and limited intra-articular joint injections (≤2). After a 90-day period of non-response for a treatment failure, effectiveness or failure of subsequent treatment was assessed again for the index biologic or new biologic (after switching). Post-index RA-related medical, pharmacy, and drug administration costs were attributed to the index biologic. Cost per patient-year in response was calculated as RA-related costs divided by duration of response.

RESULTS: Overall, 15.0% of patients (1229/8193) did not fail any criterion for 2 years and were effectively treated. Mean duration of response was highest for etanercept (538.3 days), followed by golimumab (537.0 days; p = 0.864), adalimumab (534.7 days; p = 0.301), certolizumab (524.0 days; p = 0.165), infliximab (480.0 days; p < 0.001), and abatacept (482.3 days; p < 0.001). Total disease-related cost per patient-year in response was lower for patients initiated on etanercept ($25,086) than for patients initiated on adalimumab ($25,960), certolizumab ($26,339), golimumab ($26,332), abatacept ($35,581), or infliximab ($36,107).

LIMITATIONS: This study was limited to employer-paid commercial insurance. Database analyses cannot determine reasons for failing criteria. The algorithm was not designed and validated for 2 years of follow-up.

CONCLUSIONS: An effectiveness algorithm estimated that initiating etanercept was the most effective treatment during 2 years of follow-up, with the lowest cost per patient-year in response.