In a nonrandomized study, hematopoietic recovery kinetics were evaluated in 98 consecutive patients who underwent high-dose chemotherapy without total body irradiation (TBI) and autologous peripheral blood stem cell transplantation (PBSCT). Fifty-three patients received recombinant human granulocyte colony-stimulating factor (rhG-CSF) (filgrastim) therapy after PBSCT, and the data were compared by actuarial analysis to those of 45 historic controls. The number of days required to achieve a white blood cell count (WBC) of 1 x 10(9)/L, an absolute granulocyte count (AGC) of 5 x 10(8)/L, and a platelet count (PLT) of 5 x 10(10)/L were, respectively, 12.8 +/- 6.4 (mean +/- standard deviation [SD]), 13.4 +/- 6.4, and 49.2 +/- 78.2 in treated patients vs. 12.8 +/- 4.6, 14.4 +/- 10.3, and 31.4 +/- 38.8 days in historic controls, with no significant differences. There was no significant difference between the average number of days with fever in the treated group (6.0 +/- 6.6) and that in the control group (4.0 +/- 2.8). All febrile episodes responded promptly and successfully to parenteral antibiotic therapy. Thus, the data may suggest the possibility that therapy with filgrastim has only a limited ability to enhance hematopoietic recovery after PBSCT. To confirm this notion, we initiated a prospective randomized trial by recruiting a larger number of patients.