Trends in Use of Granulocyte Colony-Stimulating Factor Following Introduction of Biosimilars Among Adults With Cancer and Commercial or Medicare Insurance From 2014 to 2019.

Importance The introduction of biosimilars and novel delivery devices between 2014 and 2019 may have changed the utilization of granulocyte colony-stimulating factors (G-CSF). Objective To assess utilization trends of G-CSFs for primary prophylaxis of febrile neutropenia (FN) among patients with cancer receiving myelosuppressive chemotherapy with commercial or Medicare insurance. Design, Setting, and Participants This cross-sectional study assessed G-CSF utilization trends overall and stratified by regimen febrile neutropenia risk level. Associations between patient characteristics and G-CSF use were evaluated. Patients with cancer, including breast, lung, colorectal, esophageal and gastric, pancreatic, prostate, ovarian, and non-Hodgkin lymphomas, initiating myelosuppressive chemotherapy courses were included from the 2014 to 2019 commercial insurance and 2014 to 2018 Medicare fee-for-service claims databases. Data were analyzed from March to June 2021. Exposures Year of chemotherapy initiation. Main Outcomes and Measures The main outcomes were use and trends of G-CSFs for primary prophylaxis, from completion to 3 days after in the first chemotherapy cycle. Results In total, 86 731 chemotherapy courses (mean [SD] age, 57.7 [11.5] years; 57 838 [66.7%] women and 28 893 [33.3%] men) were identified from 82 410 patients in the commercial insurance database and 32 398 chemotherapy courses (mean [SD] age, 71.8 [8.3] years; 18 468 [57.0%] women and 13 930 [43.0%] men) were identified from 30 279 patients in the Medicare database. Among the commercially insured population, 39 639 patients (45.7%) received G-CSFs, and 12 562 patients (38.8%) received G-CSFs among Medicare insured patients. Overall G-CSF use increased significantly throughout the study period in both populations, from 45.1% (95% CI, 44.4%-45.7%) of patients in 2014 to 47.5% (95% CI, 46.5%-48.5%) of patients in 2019 (P = .001) in the commercially insured population and from 36.0% (95% CI, 34.2%-38.0%) of patients in 2014 to 39.1% (95% CI, 38.1%-40.1%) of patients in 2018 (P < .001) in the Medicare population. The greatest increases in G-CSF use were observed among patients with high FN risk, from 75.0% (95% CI, 74.1%-76.0%) of patients to 83.2% (95% CI, 82.0%-84.2%) of patients (P < .001) among the commercially insured population and 75.3% (95% CI, 71.8%-78.6%) of patients to 86.2% (95% CI, 84.7%-87.6%) of patients (P < .001) among the Medicare population. Use of G-CSFs decreased in the commercially insured population among patients with intermediate FN risk (from 27.5% [95% CI, 26.4%-28.5%] of patients to 20.4% [95% CI, 19.1%-21.7%] of patients; P < .001) or low FN risk (from 19.3% [95% CI, 18.3%-20.4%] of patients to 16.3% [95% CI, 14.7%-18.0%] of patients; P < .001) and remained stable in the Medicare population (intermediate risk: from 26.4% [95% CI, 23.8%-29.2%] of patients to 28.4% [95% CI, 27.0%-29.8%] of patients; P = .35; low risk: from 19.6% [95% CI, 17.0%-22.4%] of patients to 20.9% [95% CI, 19.6%-22.3%] of patients; P = .58). Factors associated with increased odds of G-CSF use included older age (commercial insurance: adjusted odds ratio [aOR], 1.50 [95% CI, 1.41-1.59]; Medicare: aOR, 1.36 [95% CI, 1.08-1.71]), receiving a regimen with high FN risk (commercial insurance: aOR, 16.01 [95% CI, 15.17-16.90]; Medicare: aOR, 17.17 [95% CI, 15.76-18.71]), and history of neutropenia (commercial insurance: 3.90 (3.67-4.15); Medicare: 3.82 (3.50-4.18). Conclusions and Relevance This cross-sectional study found that utilization of G-CSFs increased among patients with cancer with high FN risk in both a commercially and Medicare-insured population, but 14% to 17% of patients still did not receive preventive treatment.