Medication use among lung cancer patients before and after initiating immune checkpoint inhibitors: A population study.

e21119 Background: Polypharmacy is an independent prognostic factor in older patients with lung cancer treated with immune checkpoint inhibitors (ICIs). Previous studies have shown that steroids, opioids, proton pump inhibitors, fluoroquinolone are associated with worsening overall survivals for lung cancer patients. The prevalence of drug use among lung cancer patients using ICIs is understudied. Methods: The study population consisted of older adults (aged 65 years or older) diagnosed with lung cancer from January 1, 2011, to December 31, 2016, in the Surveillance, Epidemiology, and End Results–Medicare linked database. Patients with a diagnosis of lung cancer and a claims record showing nivolumab plus ipilimumab combination therapy or anti–PD-1 therapy (ie, pembrolizumab or nivolumab) as their ICI prescribed were included in the analyses. Index date was defined as the date of first dose of ICIs. We examined medication usage within 90 days prior and after index date. Drug categories were classified, by mechanism of action from Lexicomp®, using Medicare Part D Drug event generic name. Descriptive analysis was used to show the percentage of concurrent drug usage for each drug category. McNemar test was used to compare the drug use prevalence before and after index day. Results: There are 669 patients in the study (male [48.56%], 65–74-year-old [67.10%]). Usage of steroids (89.09%), opioids (87.89%) was high before ICIs. Significant decreases were observed between before and after the index day for most prescribed drug categories, including anti-psychotics (-62.94%, p < .0001). But the use of thyroid products (35.83%, p < .0001) increased in usage after starting ICIs. Conclusions: To our knowledge, this is the first population-based study to quantify concurrent medication use amongst lung cancer patients undergoing immunotherapy. This study suggests the polypharmacy decreased significantly after initiation of ICIs. Future studies are required to investigate the reasons for the changes in medication use and increased utilization of thyroid products.[Table: see text]