Abstract A81: Relationship between out-of-pocket cost and use of tyrosine kinase inhibitors for the treatment of chronic myeloid leukemia

Abstract

Abstract Targeting tyrosine kinase activity in cancer cells represents one of the greatest innovations in cancer treatment. Yet the high cost of tyrosine kinase inhibitors (TKIs) and the cumulative financial burden to patients associated with their use may lead to disparities in medication adherence. This study investigated the relationship between out-of-pocket cost and adherence to TKIs among a cohort of commercially insured chronic myeloid leukemia (CML) patients. The Truven Health Marketscan database was used to identify prevalent cases of CML with >1 prescription claim for a guideline-recommended first-line TKI, imatinib, nilotinib, or dasatinib. Out-of-pocket cost was calculated longitudinally using any amount paid by the patient towards a deductible, copayment, and coinsurance. Adherence was assessed using the medication possession ratio (MPR), calculated between the first and last TKI claims occurring between 2011 and 2013, and conditional on continuous insurance plan enrolment. Nonadherence was classified as an MPR <80%. In addition to out-of-pocket cost, insurance plan, region, and area-level socioeconomic variables were assessed as determinants of adherence using logistic regression modeling to calculate and odds ratio (OR) and 95% confidence interval (CI). A total of 5,669 CML patients were identified from the Marketscan database between 2011 and 2013. Over that time period out-of-pocket costs for a 30-day supply of TKIs ranged from $0 to $1800, with means of $60 for dasatinib, $65 for imatinib, and $72 for nilotinib. Patients with relatively higher out-of-pocket costs (highest 75th percentile) were 27% more likely (OR 1.27, 95% 1.22 – 1.32) to be nonadherent to TKI therapy than patients with lower out-of-pocket costs. With the possibility of a generic version of imatinib on the horizon, understanding the association between out-of-pocket costs and adherence may have important implications for reducing disparities in adherence to TKIs for the treatment of CML. Citation Format: Jean A. McDougall, Caroline S. Bennette, Scott D. Ramsey, Sean D. Sullivan. Relationship between out-of-pocket cost and use of tyrosine kinase inhibitors for the treatment of chronic myeloid leukemia. [abstract]. In: Proceedings of the Eighth AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 13-16, 2015; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2016;25(3 Suppl):Abstract nr A81.