Patients with high out-of-pocket costs are less likely to adhere to tyrosine kinase inhibitor (TKI) treatment plans for chronic myeloid leukemia (CML), according to an article published in Cancer.1

Adherence to oral medications is known to be a serious issue for patients with CML, as non-adherence can lead to TKI resistance, shorter survival, and higher long-term treatment-related costs. The high costs of TKIs, including imatinib, nilotinib, and dasatinib, increase the risk of non-adherence.

As CML is most-often diagnosed among patients aged 65 to 74 years, insurance status at diagnosis may be a predictor for adherence to TKI therapy. Medicare Part D is a program introduced in 2006 that provides subsidies for elderly patients, though the subsidy depends on the patient’s income status. For this study, researchers evaluated health and financial data from 836 patients with CML who were insured through Medicare Part D to determine factors that may predict non-adherence.

In the overall cohort, 195 were heavily subsidized, 130 were moderately subsidized, and 511 received no subsidy. Just over 70% (592 patients) were adherent; 244 were non-adherent.

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Higher out-of-pocket costs for a 30-day drug supply were linked to non-adherence ($829 vs $567 for adherent patients; P = .005).

The researchers noted, however, that heavily subsidized patients were less likely to adhere to medication regimens, despite relatively low out-of-pocket costs. One hundred and forty unsubsidized patients were non-adherent; only 33 and 71 moderately and heavily subsidized patients were non-adherent, respectively (P = .36).

The odds ratio of non-adherence was 6.69 for heavily subsidized patients vs unsubsidized patients, though this figure decreased to 1.7 when out-of-pocket costs were excluded from the analysis.

To explain this finding, the authors noted that “[g]iven the eligibility criteria for subsidies, the patients with subsidies had lower income and fewer economic resources.”

A previous study noted a $30 median 30-day TKI supply copayment for privately insured patients. The median out-of-pocket cost was $452 for the same supply among patients included in this study.

Reference

  1. Shen C, Zhao B, Liu L, Shih YC. Adherence to tyrosine kinase inhibitors among Medicare Part D beneficiaries with chronic myeloid leukemia. Cancer. 2017 Oct 4. doi: 10.1002/cncr.31050 [Epub ahead of print]