While tyrosine kinase inhibitors (TKIs) are extending the lives of patients with chronic myeloid leukemia (CML) to spans similar to those of disease-free individuals, missing as few as 3 doses a month can cause loss of response and treatment failure.1

The high cost of TKIs continues to be a leading cause of nonadherence to therapy, but a new study found that even in cases of heavily subsidized treatment, lower-income patients still have much lower adherence — suggesting that a host of other factors may be involved and that more comprehensive interventions are needed if adherence is to be improved.2

“For most people cost is an issue,” said the study’s lead author, Chan Shen, PhD, MS, assistant professor in the department of health services research at the University of Texas MD Anderson Cancer Center in Houston. “For some disadvantaged people who have very limited financial means, their problem is not only cost but multifaceted. They have access issues, education issues, family support issues, issues around drug knowledge, and behavioral problems. They have a lot of other issues that need to be dealt with to improve their adherence.”

Several studies have linked the cost burden of TKI therapy with nonadherence, visibly and dramatically affecting low-income Medicaid recipients and those with high out of pocket (OOP) costs.

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One 2014 analysis of 473,722 patients in the SEER database concluded that “among patients with the 10 most deadly cancers, those with Medicaid coverage or without insurance were more likely to present with advanced disease, were less likely to receive cancer-directed surgery and/or radiation therapy, and experienced worse survival.”3

Although TKI therapy is highly effective, it is expensive, and may cost $146,000 per year on average if a patient is uninsured. High expenses make it difficult even for insured patients to meet their copayments and coinsurance costs.

That’s particularly significant for Medicare Part D patients, according to the recent study’s authors.

“Indeed, we found that patients with CML in the current study who were covered by Medicare Part D had much higher OOP costs for a 30-day supply of TKIs and the nonadherence rate also was much higher. More specifically, the median OOP cost for a 30-day supply was $452 in the current study cohort compared with the $30 median copayment for the privately insured patients in [a] previous study; the corresponding nonadherence rates were 29% compared with 23%, respectively.”