Patterns of Tumor Necrosis Factor Inhibitor (TNFi) Biosimilar Use Across United States Rheumatology Practices

Abstract

Objective. It is unclear if biosimilars of biologics for inflammatory arthritis are realizing their promise to increase competition and improve accessibility. This study evaluates biosimilar tumor necrosis factor inhibitor (TNFi) utilization across rheumatology practices in the United States and compares whether patients initiating biosimilars remain on these treatments at least as long as new initiators of bio-originators.Methods. We identified a cohort of patients initiating a TNFi biosimilar between January 2017 and September 2018 from an electronic health record registry containing data from 218 rheumatology practices and over 1 million rheumatology patients in the United States. We also identified a cohort of patients who initiated the bio-originator TNFi during the same period. We calculated the proportion of biosimilar prescriptions compared with other TNFi's and compared persistence on these therapies, adjusting for age, sex, diagnoses codes, and insurance type.Results. We identified 909 patients prescribed the biosimilar infliximab-dyyb, the only biosimilar prescribed, and 4413 patients with a new prescription for the bio-originator infliximab. Biosimilar patients tended to be older, have a diagnosis code for rheumatoid arthritis, and covered by Medicare insurance. Over the study period, biosimilar prescriptions reached a maximum of 3.5% of all TNFi prescriptions. Patients persisted on the biosimilar at least as long as the bio-originator infliximab (hazard ratio [HR] 0.83, P = 0.07).Conclusion. The uptake of biosimilars in the United States remains low despite persistence on infliximab-dyyb being similar to the infliximab bio-originator. These results add to clinical studies that should provide greater confidence to patients and physicians regarding biosimilar use.

Effect of listing strategies on utilization of antitumor necrosis factor biologics infliximab and etanercept: a cross-sectional analysis from Ontario, Canada

“…2 For the anti-TNF drugs infliximab and etanercept, biosimilars accounted for only 4.7% of the total spending on these 2 drugs in 2018. 2 Similarly, in the United States, biosimilar anti-TNFs represented only 3.5% of all anti-TNF prescriptions, 6 although contributing factors, including cost and coverage aspects, may differ between countries. The overall uptake of biosimilars in North America remains much lower than Europe, which accounts for 80% of the biosimilar use globally.…”

Uptake and Spending on Biosimilar Infliximab and Etanercept After New Start and Switching Policies in Canada: An Interrupted Time Series Analysis

“…Biosimilars offer one potential avenue to decrease spending on biologics, and projections suggest that they could reduce drug expenditures by $215 billion globally between 2022 and 2026 (1). Despite this potential, biosimilar uptake has been low in some countries, including the US and Canada (6)(7)(8)(9)(10).…”

Patient perspectives on the British Columbia Biosimilars Initiative: a qualitative descriptive study

“…Presently, biosimilars are thought to cost 25% to 50% less than their originator drug, and the potential cost savings from the use of biosimilars in Canada by 2021 have been estimated to be as high as $842 million [12,13]. To date, there has been a lack of biosimilar uptake in Canada and the United States, suggesting that these potential cost-savings have not yet been realized [10,14].…”