549P - Impact of concomitant medications on disease free survival (DFS) and overall survival (OS) in patients from the PETACC8 study

Impact of comedications and comorbidities upon OS isn’t well described in cancer patients (pts). We aimed to evaluate their impacts on DFS and OS on pts resected from a stage III colon cancer and treated by adjuvant FOLFOX-4 +/- cetuximab in the PETACC8 study. Treatments (trts) categories were defined according to the WHO ATC classification system. We focused on 4 medication classes: anticoagulant, cardiovascular, antidiarrheal and antidiabetic trts. We classified the 2559 pts in each category if they took trt at baseline or during study whatever the duration was. Kaplan-Meier method and Cox model were used to compare survival curves. Multivariate analyses were performed on the overall population and according to trt arm. Only 1% of pts had no comedications. Comedications with anticoagulant, cardiovascular, antidiarrheal and antidiabetic trts were observed respectively in 18%, 40%, 30% and 9% of the cases. Patients with antidiabetic or cardiovascular trts had more comorbidities. For each other comedication categories, baseline characteristics were balanced between pts treated or not. All comedication categories, except antidiarrheals, were associated with a significant decrease of DFS and OS (Table). Dose-intensity was balanced and may not explain survival differences. For pts treated with at least one cardiac, diabetic or anticoagulant trts, severe events were more frequently reported, including 9 early deaths. The use of antidiarrheals is maybe associated to a better exposure to chemotherapy as reflected by a higher rate of grade ≥3 adverse events but also a potential better efficacy. Table. Comedications impact on DFS and OS.Table549PTableOverall analysisDFSOSHR [95%CI]pHR [95%CI]pAnticoagulantsIntake vs no1.33 [1.10–1.62].0031.34 [1.07–1.67].01AntidiarrhealsIntake vs no0.87 [0.73–1.04].120.78 [0.63–0.96].02Cardiovascular trtsIntake vs no1.20 [1.03–1.41].021.28 [1.07–1.54].01AntidiabeticsIntake vs no1.37 [1.07–1.76].011.45 [1.09–1.92].01 Comorbidities related to analyzed ATC classes negatively impact OS and DFS in PETACC8 pts, except antidiarrheal agents which positively impact OS and DFS. PETACC8; 2005-003463-23. Fédération Francophone de Cancérologie Digestive, Dijon. Merck and Sanofi. J. Taieb: Advisory / Consultancy: Merck; Advisory / Consultancy: Sanofi; Advisory / Consultancy: Roche Genentech; Advisory / Consultancy: Pfizer; Advisory / Consultancy: Amgen. All other authors have declared no conflicts of interest.