A time series analysis of immune checkpoint inhibitor use in the United States Medicare population: 2014-2019

Background The adoption of immune checkpoint inhibitors (ICIs) has dramatically transformed the treatment of numerous cancers. Medicare is the largest payer in the US and pays for physician-administered drugs through its medical Part B benefit. The aim of this study was to describe trends in ICI utilization and corresponding government expenditures within the US Medicare population. Methods We analyzed Medicare data to describe trends in total number of claims, total annual expenditures, expenditures per patient, and expenditures per claim for ICIs from January 2014 to December 2019. Results From 2014 to 2019, utilization rates for each of the seven market approved ICIs in the US increased. Over this time period, total Medicare expenditure on ICIs increased 1916% from $285,506,498 to $5,755,319,571. Concurrently, overall Medicare Part B drug expenditure increased 57% from $23,679,547,748 to $37,271,080,631. Expenditures on ICIs accounted for 40% of the increase in total Medicare Part B drug spending over this time period. Conclusions The rapid increase in utilization of ICIs has accounted for a disproportionate share of government drug spending growth in the United States. Policymakers can potentially curb spending growth by linking payments to patient outcomes.