Direct oral anticoagulants in patients with venous thromboembolism and hematological malignancies

Data are needed on direct oral anticoagulants (DOACs) for the treatment of venous thromboembolism (VTE) in hematological malignancies (HM). Retrospective studies to date lacked a control group and did not focus on patients with VTE. Out aim was to assess the incidence of VTE recurrence and bleeding in HM patients treated with low molecular weight heparin (LMWH) or DOACs for acute VTE. This is a retrospective cohort study including patients with active HM and newly-diagnosed VTE, indexed on the first day of anticoagulation and followed for 12 months. The outcome was a composite of recurrent VTE, major bleeding or clinically relevant non-major bleeding. Cumulative incidence [95% confidence interval (CI)] was calculated for each anticoagulation group (LMWH, DOAC) and hazard ratios (HR) were calculated using cox-proportional hazards model, with death as a competing risk. 143 HM patients treated with LMWH (96) or DOACs (47) for acute VTE were included. The most common HM types were lymphoma in 83 (58%) and plasma cell dyscrasia in 32 (22.3%). The 12-month cumulative incidence of the composite outcome was 24.2% (95% CI 15.9-33.5%; n = 22) in the LMWH group and 18.5% (8.5-31.5%; n = 8) in the DOAC group (HR 1.51 [0.695-3.297]). Two recurrent VTE occurred (both in the DOAC group while off-treatment). Nine (9.4%) LMWH-treated patients had major bleeding compared to 1 (2.1%) DOAC-treated patient (HR 4.85 [0.64-36.56]). This study generates the hypothesis that DOACs may be a safe and effective alternative to LMWH for VTE in patients with HM types represented in the study.