Financial Impact of Treatment Choice in CML: A Comparison of Later Generation TKIs Versus Imatinib for US Patients and Payers

INTRODUCTION: Later-generation tyrosine kinase inhibitors (TKIs) have achieved deeper and more rapid molecular responses in chronic myeloid leukemia (CML) compared to first-generation TKI imatinib. However, the cost of these newer treatments has raised concerns about the financial impact imparted to patients and payers. This study measured the financial impact, as the burden to patients based on either (i) out-of-pocket (OOP) costs or (ii) changes in insurance premiums, of newer TKIs relative to imatinib in publicly and privately insured US populations.

METHODS: Patient financial impact was measured as the difference in expected annual OOP cost between newer TKIs (asciminib, bosutinib, dasatinib, nilotinib, ponatinib) versus imatinib by payer type. TKI costs were based on 2024 wholesale acquisition costs (WACs); imatinib cost was calculated as a weighted average of generic and brand WAC based on real-world market share. Annual payer OOP maximums for traditional Medicare were those established by the Inflation Reduction Act (IRA) Medicare Part D benefit redesign, commercial OOP maximums were obtained from the 2023 KFF Employer Health Benefits Survey, and the Medicaid OOP annual copayment maximum ($200) was drawn from NY Medicaid. Premium-related financial impact was measured as change in monthly premium based on per member per month (PMPM) budget impact, calculated as the difference in annual per person treatment cost between newer TKIs and imatinib multiplied by the prevalence of the respective indicated CML populations (Philadelphia chromosome positive (Ph+) CML in 1L, 2L, or ≥3L) by payer type. Annual per person treatment cost was estimated as the weighted average across indicated populations using recommended dosing and WACs. US prevalence of indicated CML populations by payer was estimated using Surveillance, Epidemiology, and End Results Program (SEER) data and real-world distributions of indicated populations from literature.

RESULTS: Annual WACs for imatinib averaged $23,101 ($1,550-$33,612 across generics, $123,105 for branded) and >$100,000 for all newer TKIs. Pharmaceutical costs for all CML therapies exceeded OOP limits under traditional Medicare ($2,000), average commercial plan ($4,101), and commercial plan with highest possible annual OOP limit (ACA maximum of $9,450), resulting in no change in patient OOP cost whether they were on a newer TKI or imatinib among these insured CML patients. Similarly, copays for generic and preferred brands ($1 per prescription) versus non-preferred brands ($3 per prescription) among Medicaid beneficiaries with CML led to $0-$24 annual difference in OOP cost with newer TKIs vs. imatinib, depending on newer TKIs’ preferred status. Even when considering generic imatinib only (average $6,502), publicly-insured patients would exceed OOP limits, while commercial plan patients would reach OOP limits due to medical care costs alone (typical OOP non-pharmacy medical care costs range between $9,806/year in 1L to $25,978/year in 3L+). Difference in payer PMPM budget impact from imatinib varied by newer TKI, ranging $0.15-$1.05, with higher monthly premium increases for Medicare ($0.44-$2.48) compared to Medicaid or commercial ($0.12-$0.81) enrollees.

CONCLUSIONS: Maximum OOP caps are designed to provide a safety net for patients. Assuming no other medical or pharmacy cost, in a study across Medicare, Medicaid, and commercial health plans, both imatinib and newer TKI costs exceeded annual OOP caps for insured CML patients. In short, annual OOP spend would be comparable for insured US patients regardless of whether they choose imatinib or newer TKIs. This analysis did not consider payer-negotiated rebates or manufacturer assistance programs (MAPs); thus, actual cost differentials between newer TKIs and imatinib for payers and patients may be smaller than estimated in this study. Moreover, CML is a relatively rare cancer and, thus, the impact of CML treatment choice on health plan premiums is likely to be minimal.