PROGENITOR-CELL MOBILIZATION AFTER LOW-DOSE CYCLOPHOSPHAMIDE AND GRANULOCYTE-COLONY-STIMULATING FACTOR - AN ANALYSIS OF PROGENITOR-CELL QUANTITY AND QUALITY AND FACTORS PREDICTING FOR THESE PARAMETERS IN 101 PRETREATED PATIENTS WITH MALIGNANT-LYMPHOMA

Purpose: To define parameters that predict for rapid engraftment after peripheral-blood stem-cell (PBSC) transplantation, progenitor thresho lds, the proportion of patients who achieve these thresholds with a st andardized mobilization regimen, and the factors that predict for mobi lization efficiency. Patients and Methods: One hundred and one patient s with pretreated lymphoma were mobilized with cyclophosphamide 1.5 g/ m(2) and granulocyte colony-stimulating factor (G-CSF), with the first apheresis performed when the recovery WBC count was greater than or e qual to 5.0 x 10(9)/L. The relationship between the number of progenit or cells collected and patient age, sex, diagnosis, prior radiotherapy , and time since last chemotherapy was determined by multivariate anal ysis. The relationship between these factors, progenitor numbers retur ned, post-PBSC G-CSF, and hematologic recovery was performed in 81 pat ients following chemotherapy with carmustine (BCNU), etoposide, cytara bine, and melphalan (BEAM protocol). Results: No BEAM recipients had d elayed neutrophil recovery beyond 28 days. Delayed platelet recovery o ccurred in 7.4% and minimum and optimum thresholds of 1 x 10(6) and 3. 5 x 10(6) CD34(+) cells/kg and 1 x 10(5) and 3.5 x 10(5) granulocyte-m acrophage colony-forming cells (GM-CFC)/kg were established. Hematolog ic recovery was adversely affected by prior treatment with mini-BEAM, and neutrophil recovery was accelerated by post-PBSC G-CSF. The minimu m GM-CFC threshold was achieved with a single apheresis in 83% of pati ents and in 90% with two aphereses. The optimal threshold was achieved with two leukaphereses in 69% of patients. Prior radiotherapy adverse ly affected mobilization. Conclusion: Hematopoietic recovery following PBSC is dependent on progenitor-cell number infused and affect of pre vious chemotherapy on progenitor quality, Progenitor-cell mobilization is adversely affected by prior radiotherapy. The minimum threshold of GM-CFC required is achieved in most patients with a single apheresis, but an optimal collection usually requires at least two harvests. (C) 1997 by American Society of Clinical Oncology.