A 28-year-old woman presents to the emergency department with a 5-day history of severe mucosal bleeding, petechiae, and epistaxis. CBC shows WBC 3,200/μL (normal), Hb 8.2 g/dL, platelets 18,000/μL. Coagulation studies reveal INR 2.8, aPTT 65 sec, fibrinogen 65 mg/dL. Bone marrow aspirate smear shows abnormal promyelocytes, and the structure marked **A** (faggot cell with bundle of Auer rods) is identified. Which of the following is the MOST appropriate immediate management for this patient?