The costs of treating and not treating patients with chronic myeloid leukemia with tyrosine kinase inhibitors among Medicare patients in the United States.

BACKGROUND Patients with high cost-sharing of tyrosine kinase inhibitors (TKIs) experience delays in treatment for chronic myeloid leukemia (CML). To the authors' knowledge, the clinical outcomes among and costs for patients not receiving TKIs are not well defined. METHODS Using the Surveillance, Epidemiology, and End Results (SEER)-Medicare database, the authors evaluated differences in TKI initiation, health care use, cost, and survival among patients with CML with continuous Medicare Parts A and B and Part D coverage who were diagnosed between 2007 and 2015. RESULTS A total of 941 patients were included. Approximately 29% of all patients did not initiate treatment with TKIs within 6 months (non-TKI users), and had lower rates of BCR-ABL testing and more hospitalizations compared with TKI users. Approximately 21% were not found to have any TKI claims at any time. TKI initiation rates within 6 months of diagnosis increased for all patients over time (61% to 85%), with greater improvements observed in patients receiving subsidies (55% to 90%). Total Medicare costs were greater in patients treated with TKIs, with approximately 50% because of TKI costs. Non-TKI users had more inpatient costs compared with TKI users. Trends in cost remained significant when adjusting for age and comorbidities. The median overall survival was 40 months (95% confidence interval [95% CI], 34-48 months) compared with 86 months (95% CI, 73 months to not reached), respectively, for non-TKI users versus TKI users, a finding that remained consistent when adjusting for age, comorbidities, and subsidy status (hazard ratio, 2.23; 95% CI, 1.77-2.81). CONCLUSIONS Approximately 21% of all patients with CML did not receive TKIs at any time. Cost-sharing subsidies consistently are found to be associated with higher initiation rates. Non-TKI users had higher inpatient costs and poorer survival outcomes. Interventions to lower TKI costs for all patients are desirable.