COMPARABLE ENGRAFTMENT KINETICS FOLLOWING PERIPHERAL-BLOOD STEM-CELL INFUSION MOBILIZED WITH GRANULOCYTE-COLONY-STIMULATING FACTOR WITH OR WITHOUT CYCLOPHOSPHAMIDE IN MULTIPLE-MYELOMA

Purpose: To compare, in the setting of tandem autotransplantations for multiple myeloma (MM), two established methods of peripheral-blood st em-cell (PBSC) procurement with chemotherapy or hematopoietic growth f actor alone. Patients and Methods: Between June 1994 and July 1995, 44 patients with MM were randomized to PBSC mobilization with either gra nulocyte colony-stimulating factor (G-CSF) 16 mu g/kg (group 1; n = 22 ) or high-dose cyclophosphamide (HDCTX) 6 g/m(2) plus G-CSF 5 mu g/kg (group 2; n = 22). All 44 patients received melphalan 200 mg/m(2) with their first autograft and 32 patients proceeded to a second transplan tation. Results: Group 2 required a significantly longer time interval for completion of PBSC collection than group 1 (median, 22 v 8 days; P = .0001), greater frequency of hospitalization (100% v 32%; P = .000 1), and increased transfusion of platelets (86% v 18%; P = .0001) and packed RBCs (86% v 55%; P = .02). Likewise, the incidence of fever and pneumonia/sepsis were higher in group 2 (P = .02 and P = .04, respect ively). Surprisingly, despite greater CD34 cell quantities infused in group 2, median recovery times of granulocytes (both > 500/mu L and 2, 500/mu L) and platelets (both > 50,000/mu L and > 100,000/mu L) were s imilar (all P > .7). Posttransplant toxicities were also similar. Conc lusion: Compared with HDCTX plus G-CSF, high-dose G-CSF alone is assoc iated with lower morbidity, shorter duration of PBSC mobilization, and comparable hematopoietic recovery after transplantation, which should result in significant cost reduction. Considering the relatively limi ted antitumor activity of HDCTX (10% with greater than or equal to 50% tumor cytoreduction), PBSC mobilization with HDCTX should be limited to selected patients with persistent MM despite induction chemotherapy . (C) 1998 by American Society of Clinical Oncology.