Comparative evaluation of patients newly initiating first-generation versus second-generation tyrosine kinase inhibitors for chronic myeloid leukemia and medication adherence, health services utilization, and healthcare costs

Abstract

Background:

Chronic myeloid leukemia (CML) treatment guidelines recommend first-line therapy with either first- or second-generation tyrosine kinase inhibitors (1GTKI, 2GTKI), but do not specify which generation should be used first.

Objective:

To examine the association between initiation of 2GTKI versus 1GTKI and medication adherence, health services utilization, and healthcare costs.

Method:

This was a retrospective cohort study utilizing administrative claims data from a single health plan within the US of commercial and Medicare patients newly initiating 1GTKI or 2GTKI therapy for CML between June 2010 and December 2011. Multivariate logistic regression was used to investigate the association between TKI therapy and adherence, defined as proportion of days covered ≥0.85. Multivariate logistic regression and generalized linear models examined the association between TKI and health services utilization and direct healthcare costs (plan and patient paid) during the 12 month follow-up period.

Results:

Among the 368 patients included, there was no difference in adherence between patients initiating a 2GTKI compared to a 1GTKI (odds ratio = 0.88, 95% confidence interval [CI] 0.55–1.40). Initiating a 2GTKI was associated with increased outpatient visits (incidence rate ratio [IRR] = 1.12, 95% CI 1.06–1.20); however, there were no statistically significant differences in emergency room visits or inpatient visits between the treatment groups. Total costs were 1.3 times higher for 2GTKI initiators versus 1GTKI initiators ($86,509 versus $66,443; p = 0.001), with a significant difference in TKI pharmacy costs.

Conclusions:

Although there were no differences in adherence, hospitalizations, or emergency room visits among patients initiating a second- versus first-generation TKI, total all-cause costs and outpatient visits were higher for 2GTKI initiators. With the impending release of generic imatinib, these comparative data will become germane in the selection of a first-line TKI therapy. Because this study used claims from a single health plan, it may not be generalizable to the general population.

Keywords: :

• Adherence
• Chronic myeloid leukemia
• Tyrosine kinase inhibitors
• Healthcare costs

Transparency

Declaration of funding

This work was funded by the PhRMA Foundation. The funding organization had no role in the collection, interpretation, or reporting of the data and results. Humana Inc. provided the data for the research.

Declaration of financial/other relationships

L.E.H. has disclosed that she is employed by Humana. M.A.W. has disclosed that she was employed by Humana at the time the research was conducted. S.R.E. has disclosed that she is an employee of RTI Health Solutions. G.F., C.M.W. and S.J.B. have disclosed that they have no significant relationships with or financial interests in any commercial companies related to this study or article. K.L.R. has disclosed that she is supported by a Mentored Research Scholar Grant in Applied and Clinical Research (MSRG-12-086-01-TBG) from the American Cancer Society. She is also on the board of The Leukemia & Lymphoma Society (LLS), received travel funding from the American Cancer Society within the past year, and has been an advisory board member for Genentech and received a speaking honorarium from Celgene.

CMRO peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Acknowledgment

The authors wish to recognize Tyler Whisman, a clinical pharmacist at Humana Inc. during the time the study was conducted, for his contributions to the concept of this project.