Department of Health Management and Policy, Miami Business School, University of Miami, Miami, Florida.
Division of Health Policy and Economics, Department of Population Health Sciences, Weill Cornell Medical College, New York, New York.
JAMA Netw Open. 2021 Jan 4;4(1):e2034776. doi: 10.1001/jamanetworkopen.2020.34776.
Biosimilars, or highly similar versions of complex biologic drugs, have the potential to slow drug spending growth; however, biosimilar uptake in the United States has been slow. Little is known about barriers to biosimilar uptake following drug launch.
To examine the patient, physician, and practice characteristics associated with biosimilar use in the Medicare population.
DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study used regression analysis to estimate the association between biosimilar use and various characteristics. Medicare fee-for-service beneficiaries who received a filgrastim product or an infliximab product between the launch of a class's first biosimilar (quarter 3 2015 for filgrastim-sndz and quarter 4 2016 for infliximab-dyyb) and December 2018. Data analysis was conducted from March to November 2020.
Patient demographic characteristics and product clinical indications; physician demographic characteristics, specialty, and volume of filgrastim or infliximab biologic administration; hospital size, ownership, 340B status, academic medical center status, and system affiliation; physician office size and multispecialty status.
Administration of a filgrastim or infliximab biosimilar.
The final filgrastim sample included 25 870 patients (11 857 [45.8%] men; 14 224 [55.0%] aged 65-74 years; 22 617 [87.4%] White individuals) who had 259 178 administrations (79 017 [30.5%] biosimilar administrations), and the final infliximab sample included 14 786 patients (4765 [32.2%] men; 8773 [59.3%] aged 65-74 years; 13 467 [91.1%] White individuals) who had 174 973 administrations (9012 [5.2%] biosimilar administrations). In adjusted analyses, no patient demographic characteristics and 2 of 9 clinical indications (22.2%) were associated with biosimilar use (filgrastim, neutropenia: adjusted difference, -2.0 [95% CI, -3.9 to -0.2] percentage points; P = .03; infliximab, Crohn disease: adjusted difference, -1.8 [95% CI, -2.9 to -0.8] percentage points; P = .001). Several physician characteristics were associated with biosimilar administrations, including high filgrastim or infliximab prescribing volume (high vs low volume, filgrastim: adjusted difference, 3.6 [95% CI, 1.5 to 5.8] percentage points; P = .001; infliximab: adjusted difference, 1.2 [95% CI, 0.3 to 2.2] percentage points; P = .007) and specialty (eg, hematologist-oncologists vs primary care, filgrastim: adjusted difference, -3.0 [95% CI, -5.4 to -0.5] percentage points; P = .02). Numerous practice characteristics were associated with biosimilar use, including practice setting (outpatient hospital department vs office practice, filgrastim: adjusted difference, -16.1 [95% CI, -18.1 to -14.1] percentage points; P < .001; infliximab: adjusted difference, 3.0 [95% CI, 2.2 to 3.7] percentage points; P < .001) and hospital outpatient department ownership status (for-profit vs not-for-profit, filgrastim: adjusted difference, -17.4 [95% CI, -21.6 to -13.3] percentage points; P < .001; infliximab: adjusted difference, 10.8 [95% CI, 6.7 to 14.9] percentage points; P < .001).
In this study, practice setting and hospital ownership status had the largest associations with biosimilar usage, suggesting practices play a role in steering physicians toward certain medications. However, the types of practices with high biosimilar use differed by drug class. Further research is needed to understand the reasons for these differences across drug classes.
重要性：生物类似药，或复杂生物药物的高度相似版本，具有减缓药物支出增长的潜力；然而，美国的生物类似药采用率一直很低。关于药物推出后生物类似药采用的障碍知之甚少。
目的：研究在医疗保险人群中与生物类似药使用相关的患者、医生和实践特征。
设计、设置和参与者：本横断面研究使用回归分析来估计生物类似药使用与各种特征之间的关联。接受培非格司亭产品或英夫利昔单抗产品的医疗保险患者，这些产品在其所属类别中的首个生物类似药推出后（培非格司亭-sndz 为 2015 年第 3 季度，英夫利昔单抗-dyyb 为 2016 年第 4 季度）至 2018 年 12 月。数据分析于 2020 年 3 月至 11 月进行。
暴露：患者人口统计学特征和产品临床适应证；医生人口统计学特征、专业、培非格司亭或英夫利昔单抗生物制剂的使用量；医院规模、所有权、340B 状态、学术医疗中心地位和系统隶属关系；医生办公室规模和多专科状态。
主要结果和措施：培非格司亭或英夫利昔单抗生物类似药的使用。
结果：最终的培非格司亭样本包括 25870 名患者（11857 名男性[45.8%]；14224 名年龄 65-74 岁的患者[55.0%]；22617 名白人个体[87.4%]），他们接受了 259178 次给药（79017 次[30.5%]为生物类似药给药），最终的英夫利昔单抗样本包括 14786 名患者（4765 名男性[32.2%]；8773 名年龄 65-74 岁的患者[59.3%]；13467 名白人个体[91.1%]），他们接受了 174973 次给药（9012 次[5.2%]为生物类似药给药）。在调整后的分析中，没有患者人口统计学特征和 9 种临床适应证中的 2 种（中性粒细胞减少症：调整差异，-2.0[95%CI，-3.9 至-0.2]个百分点；P=0.03；克罗恩病：调整差异，-1.8[95%CI，-2.9 至-0.8]个百分点；P=0.001）与生物类似药的使用相关。几个医生的特征与生物类似药的管理有关，包括培非格司亭或英夫利昔单抗的高处方量（高与低量，培非格司亭：调整差异，3.6[95%CI，1.5 至 5.8]个百分点；P=0.001；英夫利昔单抗：调整差异，1.2[95%CI，0.3 至 2.2]个百分点；P=0.007）和专业（例如，血液科肿瘤学家与初级保健医生，培非格司亭：调整差异，-3.0[95%CI，-5.4 至-0.5]个百分点；P=0.02）。许多实践特征与生物类似药的使用有关，包括实践环境（门诊医院部门与办公室实践，培非格司亭：调整差异，-16.1[95%CI，-18.1 至-14.1]个百分点；P<0.001；英夫利昔单抗：调整差异，3.0[95%CI，2.2 至 3.7]个百分点；P<0.001）和医院门诊部门的所有权状况（营利性与非营利性，培非格司亭：调整差异，-17.4[95%CI，-21.6 至-13.3]个百分点；P<0.001；英夫利昔单抗：调整差异，10.8[95%CI，6.7 至 14.9]个百分点；P<0.001）。
结论和相关性：在这项研究中，实践环境和医院所有权状况与生物类似药的使用相关性最大，这表明实践在引导医生使用某些药物方面发挥了作用。然而，具有高生物类似药使用的实践类型因药物类别而异。需要进一步研究以了解不同药物类别之间这些差异的原因。
