The prevalence of relevant drug-drug interactions and associated clinical outcomes in patients with cancer-associated thrombosis on concurrent anticoagulation and anticancer or supportive care therapies

Abstract

BackgroundA main concern in the management of patients with cancer-associated thrombosis (CAT) is drug-drug interactions (DDIs) between anticoagulants and anticancer therapies. Their clinical implications remain unclear. MethodsTo quantify the prevalence of DDIs and risks of recurrent venous thromboembolism (VTE) and bleeding events in patients with CAT on anticoagulation, we conducted a retrospective cohort study in patients with CAT on concurrent anticoagulants and anticancer and/or supportive care therapies. All patients were followed for 6 months from CAT diagnosis or until death (whichever occurred first). The primary outcome was the percentage of patients with anticoagulant DDIs classified as risk C, D, or X in Lexicomp® at any time during the 6 months. Secondary outcomes included recurrent VTE and clinically relevant bleeding events. We calculated the 6-month cumulative incidence of outcomes with 95 % confidence interval (CI) and compared those with and without DDIs, considering death as a competing risk. ResultsAmong 267 patients included, 111 (41.6 %) had DDIs with anticoagulants at any time during the study. Those on DOACs at any time had more DDIs compared to LMWH (50.9 % vs 19.3 %, p < 0.0001). The 6-month incidence was 8.2 % (95 % CI 5.3–11.9) for recurrent VTE and 6.7 % (95 % CI 4.2–10.2) for clinically relevant bleeding, with no significant differences between groups with or without DDIs. ConclusionsThere are high incidences of DDIs in patients with CAT on anticoagulants, more with DOACs. DDIs classified as risk C, D, or X by Lexicomp® were not associated with recurrent VTE or bleeding events in our cohort.