PRIMARY OBJECTIVES:
I. Compare the complete response (CR) and near CR rate in patients undergoing autologous stem cell transplant (ASCT) using melphalan 280 mg/m\^2 or melphalan 200 mg/m\^2.
SECONDARY OBJECTIVES:
I. Compare toxicities between patients receiving amifostine and melphalan 280 mg/m\^2 or melphalan 200 mg/m\^2.
OUTLINE: Patients are randomized to 1 of 2 treatment arms.
INDUCTION THERAPY:
ARM I (HIGH DOSE MELPHALAN AND AMIFOSTINE): Patients receive amifostine intravenously (IV) over 3-5 minutes on days -3 and -2 followed by high-dose melphalan IV over 15-30 minutes on day 2.
ARM II (LOW DOSE MELPHALAN AND AMIFOSTINE): Patients receive amifostine as in arm I and melphalan as in arm I at a lower dose.
AUTOLOGOUS OR SYNGENEIC PERIPHERAL BLOOD STEM CELL TRANSPLANTATION (PBSCT): At least 20 hours after completion of melphalan, patients undergo autologous or syngeneic PBSCT on day 0.
Patients undergo restaging of the disease between days 80-90. Patients with progressive disease are removed from the study. Patients who achieve a CR or near-CR can proceed to optional maintenance therapy. Patients who do not achieve a CR or near-CR may undergo additional induction therapy as in arm I followed by a second autologous or syngeneic PBSCT.
Patients again undergo restaging of the disease 80-90 days later. Patients with progressive disease are removed from the study. Patients without progressive disease can proceed to maintenance therapy.
After completion of study treatment, patients are followed up every 3 months for 5 years.
