Retrospective real-world comparison of medical visits, costs, and adherence between nilotinib and dasatinib in chronic myeloid leukemia.

OBJECTIVE: To compare healthcare resource utilization, costs, and treatment adherence associated with dasatinib versus nilotinib treatment as second-line therapies in chronic myeloid leukemia (CML) patients.

METHODS: Two large retrospective claims databases (01/1999-06/2009) were combined to identify CML patients (ICD-9 code 205.1x) who received one or more prescriptions of dasatinib or nilotinib. Studied patients had continuous enrollment ≥ 1 month prior to and after the index date, defined as the first prescription for dasatinib or nilotinib. Patients were followed for up to 6 months from the index date to the earliest of the termination of healthcare plan enrollment or end of data availability. Patients with bone marrow or stem cell transplant during the study period were excluded. Poisson regression models were used to compare healthcare resource utilization between the two groups. Results were reported as incidence rate ratios (IRR). Healthcare cost differences were estimated for each cost component using generalized linear models or two-part models. Treatment adherence was measured by the proportion of days covered (PDC) and compared using generalized linear models. Multivariate regressions were used to control for potential confounding factors.

RESULTS: A total of 521 CML patients receiving second-line tyrosine kinase inhibitors (TKI) (452 dasatinib and 69 nilotinib) were studied. During the study period, dasatinib patients were estimated to have more than twice as many inpatient days (IRR = 2.44; p < 0.001) and nearly double the number of inpatient admissions (IRR = 1.99; p = 0.047) compared to nilotinib patients. Over the follow-up period, dasatinib patients incurred $8828 more in total medical service costs (p < 0.001); cost differences were mainly driven by an adjusted inpatient cost difference of $8520 (p = 0.003). Dasatinib patients were less adherent, with a PDC value approximately 13% lower compared to nilotinib patients (p = 0.009).

CONCLUSIONS: Among CML patients treated with second-line TKIs, nilotinib patients were more adherent and experienced lower healthcare resource utilization, resulting in medical service cost savings compared to dasatinib patients.