Reduced-Dose Apixaban and Rivaroxaban Versus Low-Molecular-Weight Heparin in Patients With Hematologic Malignancies

Inclusion Criteria: * Active hematologic malignancy at the time of initiation of systemic therapy, including multiple myeloma, myeloproliferative neoplasm, lymphoma or other hematologic cancer with a Khorana score ≥ 2 points (intermediate or high risk of venous thromboembolism, VTE) * Use of anticoagulant agents for primary thromboprophylaxis, including direct oral anticoagulants (DOACs) at reduced doses (apixaban 2.5 mg twice daily or rivaroxaban 10 mg once daily) or low-molecular-weight heparin (LMWH) (enoxaparin 40 mg subcutaneously once daily). Exclusion Criteria: * Major bleeding within the last month (including gastrointestinal or intracranial bleeding). * Active major bleeding. * Hemoglobin concentration \< 8 g/dL. * Thrombocytopenia with platelet count \<30 × 10⁹/L. * ECOG performance status of 3 or 4. * Expected survival \<6 months. * History of mechanical heart valve or severe mitral stenosis. * Estimated glomerular filtration rate (eGFR) \< 25 mL/min. * Hepatic impairment (ALT ≥ 3× upper limit of normal or bilirubin ≥ 2× upper limit of normal). * Acute coronary syndrome or ischemic stroke within the last 6 months. * Anticipated significant drug-drug interactions between DOACs and anticancer agents. * Known antiphospholipid syndrome (APS).