Factors Associated with Adherence to and Treatment Duration of Erlotinib Among Patients with Non-Small Cell Lung Cancer.

BACKGROUND: In lung cancer, there is an increasing number of oral agents available for patients; however, little is known about the factors associated with adherence to and treatment duration on oral medications in non-small cell lung cancer (NSCLC).

OBJECTIVE: To evaluate the clinical and demographic factors associated with adherence and treatment discontinuation, respectively, to oral oncolytics among patients with NSCLC.

METHODS: A retrospective, claims-based analysis of the Humana Research Database supplemented with medical chart review was conducted among patients with NSCLC who started an oral oncolytic between January 1, 2008, and June 30, 2013. Patients were required to be enrolled at least 1 year before the start of oral oncolytics and have no evidence of any oral oncolytic use during this period. Logistic regression models and Cox proportional hazard models were used to identify predictors associated with medication adherence and treatment duration, respectively.

RESULTS: Among all oral oncolytics, only the cohort starting on erlotinib had sufficient sample size (n = 1,452). A wide variety of factors were found to be associated with adherence. Low-income subsidy status, previous use of intravenous chemotherapy, and lower total baseline health care costs were significantly related to decreasing adherence (each P < 0.05). Additionally, increasing patient out-of-pocket cost was associated with decreasing adherence to erlotinib (P < 0.0001). Factors significantly related to longer treatment duration included low-income subsidy status (P < 0.001) and having Medicare insurance, (P = 0.0004), dual eligibility (Medicare and Medicaid, P = 0.007), and higher erlotinib out-of-pocket costs (P < 0.0001).

CONCLUSIONS: There is a need for mechanisms to be in place to identify and address barriers to care. Future research should focus on evaluating and reducing any potential risk to patient outcomes that may be associated with low adherence to or shorter treatment duration on oral chemotherapy.

DISCLOSURES: This study was supported by funding from Eli Lilly and Company to Comprehensive Health Insights, a Humana company, as a collaborative research project involving employees of both companies. Hess, Winfree, Zhu, and Oton are employees of Eli Lilly and Company. Louder and Nair are employees of Comprehensive Health Insights, which received funding to complete this research. Study concept and design were contributed by Hess, Zhu, Winfree, and Oton. Nair and Louder collected the data, and data interpretation was performed by all the authors. The manuscript was written primarily by Hess, along with Nair, and revised by Hess, Nair, Louder, and Winfree, with assistance from Zhu and Louder.