Healthcare Cost Patterns in CDK4/6 Inhibitor-Treated HR+/HER2- Metastatic Breast Cancer
- 1Comprehensive Unit for Health Economic Evidence Review and Decision Support (CHEERS), Research Organization of Science and Technology, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu, Shiga 525-8577 Japan
- 2Division of Health Policy and Management, Department of Biomedical Science, College of Life Sciences, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu, Shiga 525-8577 Japan
Abstract
Background and Objectives: Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) are standard first-line treatment for hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+/HER2-) metastatic breast cancer, yet the cost architecture across the full treatment trajectory remains poorly characterized. This study aimed to characterize phase-specific healthcare costs using a Japanese nationwide claims database.
Methods: We conducted a retrospective cohort study using the DeSC-IQVIA integrated Claims data (April 2014–May 2025). Patients with HR+/HER2- metastatic breast cancer who initiated first-line CDK4/6i were identified. Healthcare costs were decomposed into drug, non-drug inpatient, and non-drug outpatient components across eight treatment phases. Death-anchored analysis evaluated cost structure over the final 12 months of life among decedents.
Results: Among 5435 patients (median age 72.3 years), active treatment phases showed drug-dominated cost structures: first-line per-patient per-month (PPPM) cost was 482,936 Japanese yen (JPY) (drug 85%–90%), second-line 361,615 JPY (81%), and extended chemotherapy 255,922 JPY (66%). A marked inversion occurred in the palliative phase (PPPM 233,824 JPY; drug 11%, inpatient 70%) and terminal phase (PPPM 412,149 JPY; drug 17%, inpatient 69%). Death-anchored analysis of 1111 decedents identified a transition 2 months before death, when inpatient costs first exceeded drug costs. Individual fixed-effects models estimated the CDK4/6i-associated cost increment at 239,815 JPY/month (p < 0.001), corresponding to a total treatment-associated cost of 2.99 million JPY per patient.
Conclusions: The cost architecture of CDK4/6i-treated metastatic breast cancer follows a predictable trajectory from drug-dominated active treatment to hospitalization-dominated end-of-life care, with a structural transition approximately 2 months before death. These findings support phase-specific healthcare resource allocation and economic modeling.
Supplementary Information: The online version contains supplementary material available at https://doi.org/10.1007/s40261-026-01591-7.
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BibTeX
@article{kashiwa2026healthcare,
title = {{Healthcare Cost Patterns in CDK4/6 Inhibitor-Treated HR+/HER2- Metastatic Breast Cancer}},
author = {Munenobu Kashiwa and Kensuke Moriwaki},
journal = {Clinical Drug Investigation},
year = {2026},
month = sep,
doi = {10.1007/s40261-026-01591-7},
url = {https://doi.org/10.1007/s40261-026-01591-7},
note = {CC BY-NC 4.0},
}
RIS
TY - JOUR
TI - Healthcare Cost Patterns in CDK4/6 Inhibitor-Treated HR+/HER2- Metastatic Breast Cancer
AU - Munenobu Kashiwa
AU - Kensuke Moriwaki
PY - 2026
DA - 2026/09/28
JO - Clinical Drug Investigation
DO - 10.1007/s40261-026-01591-7
UR - https://doi.org/10.1007/s40261-026-01591-7
AB - Background and Objectives: Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) are standard first-line treatment for hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+/HER2-) metastatic breast cancer, yet the cost architecture across the full treatment trajectory remains poorly characterized. This study aimed to characterize phase-specific healthcare costs using a Japanese nationwide claims database. Methods: We conducted a retrospective cohort study using the DeSC-IQVIA integrated Claims data (April 2014–May 2025). Patients with HR+/HER2- metastatic breast cancer who initiated first-line CDK4/6i were identified. Healthcare costs were decomposed into drug, non-drug inpatient, and non-drug outpatient components across eight treatment phases. Death-anchored analysis evaluated cost structure over the final 12 months of life among decedents. Results: Among 5435 patients (median age 72.3 years), active treatment phases showed drug-dominated cost structures: first-line per-patient per-month (PPPM) cost was 482,936 Japanese yen (JPY) (drug 85%–90%), second-line 361,615 JPY (81%), and extended chemotherapy 255,922 JPY (66%). A marked inversion occurred in the palliative phase (PPPM 233,824 JPY; drug 11%, inpatient 70%) and terminal phase (PPPM 412,149 JPY; drug 17%, inpatient 69%). Death-anchored analysis of 1111 decedents identified a transition 2 months before death, when inpatient costs first exceeded drug costs. Individual fixed-effects models estimated the CDK4/6i-associated cost increment at 239,815 JPY/month (p < 0.001), corresponding to a total treatment-associated cost of 2.99 million JPY per patient. Conclusions: The cost architecture of CDK4/6i-treated metastatic breast cancer follows a predictable trajectory from drug-dominated active treatment to hospitalization-dominated end-of-life care, with a structural transition approximately 2 months before death. These findings support phase-specific healthcare resource allocation and economic modeling. Supplementary Information: The online version contains supplementary material available at https://doi.org/10.1007/s40261-026-01591-7.
SN - 1173-2563
SN - 1179-1918
ER -