A 44-year-old male presents with fever, chills, and myalgia for 1 week, initially treated as a common cold but with worsening fever. Over the past 2 days, he developed gingival bleeding and petechiae. Physical exam: temperature 40°C, clear lung auscultation, spleen 2 cm below the costal margin, and sternal tenderness. Laboratory tests: Hb 68g/L, WBC 46.3×10<sup>9</sup>/L, PLT 36×10<sup>9</sup>/L. Bone marrow examination confirms acute leukemia. The most appropriate management at this time is: