Roberts Eric Thomas, Bansback Nick, Tseng Chien-Wen, Shiboski Stephen, Li Jing, Schmajuk Gabriela, Yazdany Jinoos
Division of Rheumatology, Department of Medicine, University of California San Francisco, San Francisco, California, USA.
School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada.
Health Serv Res. 2025 Jun;60(3):e14410. doi: 10.1111/1475-6773.14410. Epub 2024 Dec 1.
To analyze the variability in new infliximab biosimilar starts as well as switching from bio-originator to biosimilar infliximab, across insurance payers and rheumatology practices nationally.
Data came from Rheumatology Informatics System for Effectiveness, a national registry with electronic health records from over 1100 US rheumatologists. Key outcomes include ever use of a biosimilar, date of initiation, and date of switching. Key variables of interest include insurance payer and practice.
Secondary analysis of 37,560 patients aged ≥18 years administered infliximab (bio-originator or biosimilar) between April 2016 and September 2022 in Rheumatology Informatics System for Effectiveness. We tested for differences in use of biosimilar infliximab by demographic characteristics, socioeconomic status, and diagnosis using standard mean differences and multivariable modified Poisson regression. We used generalized estimating equations to assess the adjusted effect of insurance and year of initiation on new biosimilar starts. We analyzed variation in biosimilar switching by insurance, date of switch, and practice.
A total of 8196 (21.8%) infliximab users ever used a biosimilar and use did not differ significantly by demographic or clinical characteristics. In 2022, uptake among new users was higher among those with Medicaid (55%; 95%CI 43%-68%) and private insurance (51%; 95%CI 46%-57%) compared to Medicare (36%; 95%CI 29%-43%). Few prevalent bio-originator infliximab users switched to a biosimilar, and switching was lowest among Medicare beneficiaries (7% vs. 14.2% in Medicaid and 16.9% among privately insured). In adjusted analyses, practice level differences explained 37% of variation among new biosimilar starts and 34% of variation among those switching to a biosimilar.
Our findings underscore two critical areas for enhancing biosimilar infliximab usage: increasing switching among prevalent users and increasing uptake among Medicare beneficiaries initiating treatment. Significant variation in uptake across practices also suggests that local switching policies are likely key drivers of uptake.
分析全国范围内保险支付方和风湿病诊疗机构中，英夫利昔单抗新生物类似药起始使用情况以及从原研生物药转换为生物类似药的情况的变异性。
数据来自风湿病疗效信息系统，这是一个拥有超过1100名美国风湿病学家电子健康记录的全国性登记系统。主要结果包括生物类似药的使用情况、起始日期和转换日期。感兴趣的关键变量包括保险支付方和诊疗机构。
对2016年4月至2022年9月期间在风湿病疗效信息系统中接受英夫利昔单抗（原研生物药或生物类似药）治疗的37560名年龄≥18岁的患者进行二次分析。我们使用标准均值差异和多变量修正泊松回归，测试了生物类似药英夫利昔单抗使用情况在人口统计学特征、社会经济地位和诊断方面的差异。我们使用广义估计方程来评估保险和起始年份对新生物类似药起始使用的调整效应。我们分析了保险、转换日期和诊疗机构在生物类似药转换方面的变异性。
共有8196名（21.8%）英夫利昔单抗使用者曾使用过生物类似药，且使用情况在人口统计学或临床特征方面无显著差异。2022年，与医疗保险（36%；95%CI 29%-43%）相比，医疗补助（55%；95%CI 43%-68%）和私人保险（51%；95%CI 46%-57%）的新使用者中生物类似药的使用率更高。很少有原研生物药英夫利昔单抗的现有使用者转换为生物类似药，医疗保险受益人的转换率最低（7%，而医疗补助为14.2%，私人保险为16.9%）。在调整分析中，诊疗机构层面的差异解释了新生物类似药起始使用情况变异的37%以及转换为生物类似药情况变异的34%。
我们的研究结果强调了提高生物类似药英夫利昔单抗使用率的两个关键领域：增加现有使用者的转换率以及提高医疗保险受益人中开始治疗者的使用率。不同诊疗机构之间使用率的显著差异也表明，当地的转换政策可能是使用率的关键驱动因素。
