FACTORS AFFECTING MOBILIZATION OF PERIPHERAL-BLOOD PROGENITOR CELLS IN PATIENTS WITH LYMPHOMA

The objective of this study was to identify factors associated with po or mobilization of peripheral blood progenitor cells (PBPCs) or delaye d platelet engraftment after high-dose therapy and autologous stem cel l transplantation in patients with lymphoma, Fifty-eight patients with Hodgkin's disease or non-Hodgkin's lymphoma underwent PBPC transplant ation as the ''best available therapy'' at Memorial Sloan-Kettering Ca ncer Center (New York, NY) between 1993 and 1995, PBPCs were mobilized with either granulocyte colony-stimulating factor (G-CSF) alone (n = 19) or G-CSP following combination chemotherapy (n = 39), Forty-eight of these patients underwent a PBPC transplant, receiving a conditionin g regimen containing cyclophosphamide, etoposide, and either total bod y irradiation, total lymphoid irradiation, or carmustine, A median num ber of 4.6 x 10(6) CD34+ cells/kg were obtained with a median of three leukapheresis procedures, Mobilization of PBPCs using chemotherapy pl us G-CSF was superior to G-CSF alone (6.7 x 10(6) versus 1.5 x 10(6) C D34+ cells/kg; P = 0.0002), Poorer mobilization of progenitor cells wa s observed in patients who had previously received stem cell-toxic che motherapy, including (a) nitrogen mustard, procarbazine, melphalan, ca rmustine or >7.5 g of cytarabine chemotherapy premobilization (2.0 x 1 0(6) versus 6.0 x 10(6) CD34+ cells/kg; P = 0.005), or (b) greater tha n or equal to 11 cycles of any previous chemotherapy (2.6 x 10(6) vers us 6.7 x 10(6) CD34+ cells/kg; P = 0.02), Platelet recovery to >20,000 /mu l was delayed in patients who received <2.0 x 10(6) CD34+ cells (m edian, 13 versus 22 days; P = 0.06), Patients who received greater tha n or equal to 11 cycles of chemotherapy prior to PBPC mobilization ten ded to have delayed platelet recovery to >20,000/mu l and to require m ore platelet transfusions than less extensively pretreated patients (m edian, 13.5 versus 23.5 days; P = 0.15; median number of platelet tran sfusion episodes, 13 versus 9; P = 0.17), These data suggest that curr ent strategies to mobilize PBPCs may be suboptimal in patients who hav e received either stem cell-toxic chemotherapy or greater than or equa l to 11 cycles of chemotherapy prior to PBPC mobilization, Alternative approaches, such as ex vivo expansion or the use of other growth fact ors in addition to G-CSF, may improve mobilization of progenitor cells for PBPC transplantation.