Treatment Patterns and Costs in Biologic DMARD-Naive Patients with Rheumatoid Arthritis Initiating Etanercept or Adalimumab with or Without Methotrexate

BACKGROUND: Etanercept (ETN) and adalimumab (ADA) are tumor necrosis factor inhibitors indicated for treatment of moderate to severe rheumatoid arthritis (RA) and are used as monotherapy or in combination with conventional disease-modifying antirheumatic drugs (DMARDs) such as methotrexate (MTX). Data on treatment patterns and costs of ETN and ADA as monotherapies or in combination therapy with MTX are lacking in biologic DMARD (bDMARD)-naive patients with RA. OBJECTIVE: To evaluate treatment patterns and costs of ETN and ADA monotherapy and combination therapy in bDMARD-naive patients with RA. METHODS: Data from adult bDMARD-naive patients with RA were evaluated according to index therapy (ADA or ETN as monotherapy or combination therapy with MTX) in a retrospective cohort study using the IBM MarketScan Commercial Claims and Encounters and Medicare Supplemental Databases from January 1, 2010, to June 30, 2017. Participants were bDMARD-naive for ≥ 12 months before initial ETN or ADA pharmacy claim (index date) and had continuous enrollment for ≥ 12 months pre-index and 24 months post-index. Combination therapy cohorts had an MTX claim within 30 days of the index date. Outcomes included persistence (no treatment changes or gap [≥ 60 days]); modifications to index therapy (discontinuation or switching without prior gap, restarting as switch or restart after gap, or MTX initiation/discontinuation); and mean total bDMARD costs for 2 years post-index. RESULTS: Patients on ETN monotherapy (n = 2,064) had higher persistence (26.8% vs. 21.1%, respectively; P < 0.001) on index treatment and received treatment for a longer duration (mean 375.9 days vs. 339.7 days, respectively; P < 0.001) than those on ADA monotherapy (n = 1,528). Regimen changes were more common in patients on ADA monotherapy than patients on ETN monotherapy (38.0% vs. 33.4%, respectively; P = 0.004). More patients on ADA monotherapy added MTX than those on ETN (17.5% vs. 12.6%, respectively; P < 0.001). Overall, 790 patients receiving index monotherapy had a regimen change following a gap (≥ 60 days), with a similar proportion between cohorts. Among these patients, 13.8% restarted index therapy, and 7.9% switched from index therapy. Significantly more patients receiving ETN monotherapy restarted their index regimen after a gap than those receiving ADA monotherapy (14.9% vs. 12.2%, respectively; P = 0.023). The proportion of patients persistent on combination therapy was similar between the ETN and ADA combination therapy cohorts (21.9% vs. 22.2%, respectively; P = 0.818). Treatment pattern rates were similar regardless of index combination therapy. Overall, costs for ADA were consistently higher within the index regimen throughout the follow-up period irrespective of MTX. CONCLUSIONS: ETN monotherapy as first-line treatment was associated with higher persistence, lower rate of MTX supplementation, and lower bDMARD costs than ADA monotherapy. ETN monotherapy may represent a less costly option for achieving treatment targets in bDMARD-naive patients with RA.