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).