Patients receive mitoxantrone IV, cyclophosphamide IV, and etoposide IV on day 1; and vincristine IV and bleomycin IV on day 8. Patients also receive prednisolone daily on weeks 1-4 and then every other day on weeks 5-16. Patients receive filgrastim (G-CSF) subcutaneously on days 6-12. Treatment repeats every 2 weeks for up to 8 courses (16 weeks) in the absence of disease progression or unacceptable toxicity. Patients with complete response (CR) or partial response (PR) receive 4 courses beyond CR or PR.