OBJECTIVES: TNF-inhibitors were the first biological therapies approved for RA treatment and five are approved by the US FDA: etanercept (ETN), adalimumab (ADA), infliximab (IFX), certolizumab pegol (CZP) and golimumab (GOL). The study objective was to understand “real-life” dosing patterns, including dose-escalation, which may impact costs/outcomes of TNF-inhibitor therapy. METHODS: We used a longitudinal claims database (i3 Pharma Informatics) to assess RA patients receiving ETN, ADA, or IFX. Due to product launch date, CZP and GOL were excluded. Patients having a TNF-inhibitor claim, RA diagnosis (ICD-9: 714.0), at least 6 months pre-biologic eligibility and 24-months enrollment post-claim from January 2007–March 2009 were included. Dose-escalation was defined as an increase in bi-weekly dosing from 40 to 80mg for ADA, an increase in weekly dosing from 25 to 50/100mg or 50 to 100mg for ETN, and the addition of 1 vial to the subsequent 8-weekly maintenance treatment dose, or a reduction in weeks between IFX treatments. RESULTS: A total of 59,928 patients filled a TNF-inhibitor prescription and 3448 were eligible for inclusion in this analysis. Dose-escalation rates were 13% for ADA, 3% for ETN, and 39% for IFX. Additionally, 6% of patients initiated on 25mg ETN experienced dose-escalation versus baseline. Switching to another biologic occurred in 14% (ETN), 16% (ADA) and 17% (IFX). CONCLUSIONS: These “real-life” data confirm dose-escalation occurs in clinical practice. Further analyses including all anti-TNF approvals should be performed to further elucidate the clinical and cost implications for physicians and payers. A limitation of this study is lack of standardized methodology for calculating anti-TNF doses from claims data.  Previous studies report a range of dose-escalation rates for ETN (1-17%), ADA (0-12%), and IFX (30-53%). In this study, cut-points were based on current standards of care correlated with frequency distributions within a closed system, ensuring resulting dose-escalation rates are clinically representative.