Abstract 3368: Prevalence and significance of drug-drug interactions among patients with lung cancer

Abstract

Abstract IMPORTANCE: Significant drug-drug interactions may exclude patients from clinical trials and complicate routine clinical care. Prevalence and significance of drug-drug interaction (DDI) among cancer populations is unknown. OBJECTIVE: To determine the rate of all potential drug interactions as well as the rate of major DDIs among individuals newly diagnosed with lung cancer in a national cohort. DESIGN, SETTING, AND PARTICIPANTS: We performed a retrospective cross-sectional study of adult patients in the United States Veterans’ Affairs (VA) medical system diagnosed with lung cancer between 2003 and 2016. Data were obtained from the VA Corporate Data Warehouse. Lists and categorization of potential DDIs were obtained from the Flockhart table provided by Indiana University School of Medicine. A list of commonly prohibited medications that are associated with major DDI, was determined after 11 clinical trials protocols of tyrosine kinase inhibitors in lung cancer treatment were reviewed. MAIN OUTCOMES AND MEASURES: The primary endpoint was the prevalence of exposure to all potential DDI during the three months leading up to and including the date of lung cancer diagnosis. The secondary endpoint was the prevalence of exposure to major DDIs (prohibited medications). RESULTS: Overall, 280 068 patients were included in the study. Mean age was 70 years, 98% were male, and 72% were white. Overall, 55.9% of patients were prescribed medications associated with potential DDI, and 5.1% of patients were prescribed medications with major DDIs that would be prohibited in certain clinical trials. Among the 20 most commonly prescribed drugs associated with potential DDI, only two (gemfibrozil and phenytoin) were associated with major DDI. CONCLUSIONS AND RELEVANCE: Medications with potential DDI are commonly prescribed to patients with lung cancer. However, only about 5% of patients are prescribed medications with major DDIs that would be prohibited in certain clinical trials. Further studies to determine the true clinical risk of all potential DDIs are warranted. Note: This abstract was not presented at the meeting. Citation Format: Sawsan Rashdan, Hui Yang, Tri Le, David Hsieh, Carlos A. Alvarez, David Gerber. Prevalence and significance of drug-drug interactions among patients with lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3368.