OUTLINE: Peripheral blood stem cells (PBSC) are mobilized with granulocyte colony-stimulating factor (G-CSF) for 5 days and then collected by leukapheresis. Patients receive high-dose melphalan on 2 consecutive days, followed by 1 day of rest, then by PBSC transplantation. G-CSF is given from 1 day after transplantation until the neutrophil count is greater than 1,500 for 3 consecutive days.