Apixaban or Dalteparin in Reducing Blood Clots in Patients With Cancer Related Venous Thromboembolism

PRIMARY OBJECTIVES: I. Any episode of major bleeding including fatal bleeding. SECONDARY OBJECTIVES: I. Venous thromboembolism (VTE) recurrence including deep vein thrombosis (DVT), pulmonary embolism (PE), fatal PE, or arterial thromboembolism. II. Any episode of major bleeding including fatal bleeding or any episode of clinically relevant non-major bleeding. OUTLINE: Patients are randomized to 1 of 2 treatment arms. ARM I: Patients receive apixaban 10 mg orally (PO) twice daily (BID) on days 1-7 and lower-dose apixaban 5 mg PO BID on days 8-180. ARM II: Patients receive dalteparin 200 international units (IU)/kg/day subcutaneously (SC) once daily (QD) on days 1-30 and lower-dose dalteparin 150 IU/kg/day SC QD on days 31-180. After completion of study treatment, patients are followed up at 3 months.