Abstract 14284: Anticoagulant Effects of Edoxaban in Cancer and Non-Cancer Patients With Venous Thromboembolism

Abstract

Introduction: Edoxaban, a direct oral anticoagulant (DOAC), is established as an anticoagulant medication in the treatment of venous thromboembolism (VTE) and suppression of VTE recurrences. While VTE recurrences in patients with cancer is greater than those in patients with non-cancer in spite of DOACs use, the reason is unclear. Anticoagulant effects of DOACs are not monitored because of less individual variability on their pharmacological effects and a short half-time. Although the plasma concentration of edoxaban correlates with prothrombin time (PT) and activated partial thromboplastin time (APTT) in healthy adults. PT and APTT are prolonged up to 5 hours after administration of edoxaban. Hypothesis: We hypothesized that anticoagulant effects of edoxaban are inhibited in patients with cancer and measured PT and APTT to assess its anticoagulant effects. Methods: This study is prospective observational study conducted in 12 hospitals. Patients with VTE taking edoxaban for treatment were included. PT and APTT were measured at 5-hours after first administration of edoxaban, and also measured at optional time after 7 days and/or 30 days. D-dimer, prothrombin fragment 1+2, and thrombin-antithrombin complex were measured once as coagulation markers. Results: Two hundred forty-three patients were included in the study, and 80 patients were with cancer. PT and APTT were measured at 465 points. PT and APTT at 5-hours after first administration of edoxaban were not significantly different between patients with cancer and non-cancer (17.1 ± 0.4 vs. 16.8 ± 0.3 seconds; PT, 35.1 ± 0.6 vs. 34.5 ± 0.5 seconds; APPT). PT values at 5-hours after first administration were prolonged compared with those at before administration in patients with cancer and non-cancer (13.8 ± 0.6 and 13.8 ± 0.4 seconds; before administration). Other coagulant markers were not significantly different between patients with cancer and non-cancer. Conclusions: Anticoagulant effects of edoxaban do not differ between patients with cancer and non-cancer, and those effects are sufficient. Greater VTE recurrences in patients with cancer may be due to hypercoagulable state by cancer, but not lowering anticoagulant effects of edoxaban.