Comparison of Edoxaban and Warfarin for the Treatment of Cancer-Associated Venous Thromboembolism ― A Retrospective Observational Study ―

Background: Because anticoagulant drugs for ambulatory patients with cancer-associated venous thromboembolism (CAT) are limited to warfarin and direct oral anticoagulants (DOACs) in Japan, it is important to assess the outcomes of both drugs. Methods and Results: We retrospectively assessed the outcomes of CAT patients who were treated with warfarin or edoxaban between 2011 and 2017. The assessment was limited to the duration of anticoagulant administration. CAT patients who did not receive anticoagulation therapy were also compared with the warfarin and edoxaban groups. We enrolled 111 CAT patients treated with warfarin (n=58, mean age 62.6 years, mean time in therapeutic range [TTR] % 61.1) or edoxaban (n=53, mean age 64.6 years). Although venous thromboembolism (VTE) recurred in 2 warfarin-treated patients, the 2 treatment groups were not significantly different (P=0.18). Bleeding during anticoagulation therapy occurred in 6 warfarin-treated patients (2 with major bleeding) and in 5 edoxaban-treated patients (no major bleeding) (P=1.0). The non-anticoagulation group (n=37) showed a high recurrence rate (P<0.01) compared with the anticoagulant group. Conclusions: This study showed that warfarin and edoxaban are equally effective in preventing VTE recurrence and bleeding. However, warfarin control in CAT patients presented some difficulties. This study also demonstrated the efficacy of anticoagulant drugs, compared with no anticoagulation, for CAT patients to prevent VTE recurrence.