Background: Real-world evidence specific to HR+/HER2- metastatic breast cancer (MBC) prior to introduction of CDK4/6 inhibitors is limited. In an effort to provide context for the introduction of new treatments, we assessed treatment patterns, adverse events, productivity loss, and direct/indirect economic burden in a privately insured population of patients with HR+/HER2- MBC.
Research design and methods: Using a retrospective cohort design, patients aged 18-64 years, selected from MarketScan databases (2007-2014), were analyzed using descriptive and multivariable methods.
Results: Among 5,563 eligible patients, endocrine therapy was the most common first-line (1L) therapy; its utilization trended downward from 63% (1L) to 23% (4L), with a simultaneous increase in chemotherapy use, 25% (1L) to 50% (4L). Two hundred and seventy-eight unique treatment regimens were used in the 1L setting. The average per patient monthly all-cause costs were $14,424. The 12-month indirect costs for short-term disability were substantially higher in MBC patients ($10,397) than in matched noncancer patients ($394).
Conclusion: The increasing use of chemotherapy as patients progressed to second and later lines and the substantial direct/indirect economic burden underscore an unmet need. The high number of 1L regimens highlights significant heterogeneity and a lack of consensus related to the management of HR+/HER2- MBC in routine practice.
Keywords: Adverse events; healthcare costs; healthcare use; metastatic breast cancer; productivity loss; treatment patterns.