Background/Purpose: For patients with rheumatoid arthritis (RA) receiving a biologic disease-modifying antirheumatic drug (bDMARD), the current standard of care is to use the bDMARD concurrently with a conventional synthetic DMARD (csDMARD) such as methotrexate (MTX). However, in reality, many patients may not take MTX for various reasons. This analysis aims to evaluate the trend of using bDMARDs as monotherapy in US RA patients, and to identify patient factors associated with use of monotherapy bDMARD.

Methods:  Data were drawn from the Adelphi RA-DSP, a cross-sectional survey of US rheumatologists and their RA patients, using samples from the 1^st quarter (Q1) of 2011 and Q1 2014. Rheumatologists provided information on patient demographics, insurance status, drug treatment, and patient involvement in their treatment decisions (scale: 1–5, with 4 or 5 considered to be indicative of high involvement). Patients who were currently prescribed a bDMARD without a csDMARD (monotherapy) were compared to those receiving a bDMARD in combination with a csDMARD (combination therapy). Multivariate analysis was performed to identify independent patient characteristics associated with mono- or combination therapy.

Results:  Included in the analysis were 843 RA patient records (2011: n = 453, 2014: n = 390) with mean age of 55.4 years, 72.9% female, 72.1% Caucasian, 67.7% commercially insured, 22.4% on Medicare, and 6.4% on Medicaid. Overall, 20.9% of patients currently received bDMARD monotherapy (n = 176) and 79.1% currently received combination therapy (n = 667). Overall, there was no statistically significant difference in the proportion of patients receiving monotherapy between 2011 and 2014 (20.1% vs. 21.8%, P = 0.553). However, in the subgroup of non-tumor-necrosis-factor-inhibitor (non-TNFi) users (n = 192), significant increase was seen over time in use of monotherapy bDMARD (18.2% in 2011 vs. 32.3% in 2014, P = 0.030). While among TNF users, there was no statistically significant change over time in patients receiving TNFi monotherapy (20.6% in 2011 vs. 18.5% in 2014, P = 0.553). Multivariate analysis showed that, among patients receiving TNFi, they were more likely to receive it as monotherapy if they were Caucasian (odds ratio (OR) [95% CI] = 1.772 [1.015–3.093], P = 0.044). TNFi receiving RA patients were less likely to receive monotherapy when they were insured via Medicare (OR = 0.473 [0.235–0.951], P = 0.036), or were prescribed adalimumab (OR = 0.468 [0.279–0.784], P = 0.004) or infliximab (OR = 0.379 [0.199–0.723], P = 0.003). Among patients receiving non-TNFi bDMARD, they were more likely to receive it as monotherapy when prescribed tocilizumab (OR = 2.233 [1.076–4.635], P = 0.031), but less likely if perceived by rheumatologists to be highly involved in their treatment decisions (OR = 0.289 [0.107–0.783], P = 0.015).

Conclusion:  The current study found no significant change in overall monotherapy bDMARD use from 2011 to 2014 in the US. However, there was a significant increase in the use of non-TNFi bDMARD as monotherapy from 2011 to 2014, mostly driven by anti-IL6 therapy.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/trends-and-factors-associated-with-use-of-biologic-agents-as-monotherapy-among-us-patients-with-rheumatoid-arthritis/