RE-INDUCTION CHEMOTHERAPY: Patients receive filgrastim subcutaneously (SC) on days 0-5, mitoxantrone hydrochloride intravenously (IV) over 60 minutes on days 1-3, cladribine IV over 2 hours on days 1-5, and cytarabine IV over 2 hours on days 1-5. Treatment continues for a maximum of 2 courses in the absence of disease progression or unacceptable toxicity.