ABCL-104 Direct Oral Anticoagulants for the Treatment of Venous Thromboembolism in Patients With Hematological Malignancies

Context: Data is needed on direct oral anticoagulants (DOACs) for the treatment of venous thromboembolism (VTE) in hematological malignancies (HM). Retrospective studies to date have lacked a control group and included patients with atrial fibrillation and/or VTE, but not VTE alone. Objective: Assess the incidence of VTE recurrence and bleeding in HM patients treated with low molecular weight heparin (LMWH) or DOACs for acute VTE. Design: Retrospective cohort study. Setting and Patients: The study included subjects with active HM and newly diagnosed VTE treated as inpatients or outpatients in the hemato-oncology department at Rabin or Meir Medical Centers (1/2015–7/2021). Patients were indexed on the first day of anticoagulation for VTE and followed for 12 months. Exposure: Type of anticoagulation at study index, classified as LMWH or DOAC. Main Outcome Measures: Composite of recurrent VTE, clot progression, major bleeding, or clinically relevant non-major bleeding (CRNMB). Cumulative incidence (95% confidence interval [CI]) was calculated for each anticoagulation group (LMWH, DOAC) and hazard ratios (HRs) were calculated using the Cox proportional-hazards model with death as a competing risk. Results: A total of 143 HM patients treated with LMWH (96) or DOACs (47) for acute VTE were included. HM was lymphoma in 83 (58%). DOAC-treated patients were older and had more pulmonary embolisms and less splanchnic vein thrombosis. The 12-month cumulative incidence of the primary 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 VTEs occurred (both in the DOAC group while off-treatment). Nine (9.4%) LMWH-treated patients and 1 (2.1%) DOAC-treated patient (HR 4.85 [0.64–36.56]) had major bleeding. There were 13 (13.5%) CRNMB cases in the LMWH group and 5 (10.6%) in the DOAC group (HR 1.44 [0.52–3.98]). Conclusions: This study generates the hypothesis that DOACs may be a safe and effective alternative to LMWH for VTE in patients with lymphoma or plasma cell dyscrasia. Larger prospective studies are needed to confirm these findings.