PERIPHERAL-BLOOD STEM CELL (PBSC) MOBILIZATION WITH CHEMOTHERAPY FOLLOWED BY SEQUENTIAL IL-3 AND G-CSF ADMINISTRATION IN EXTENSIVELY PRETREATED PATIENTS

Extensive pretreatment has been identified as a significant risk facto r for failure of sufficient PBSC mobilization. From published data and our own experience we defined pretreatment variables which render pat ients at risk for not collecting at least 2.5 x 10(6) CD34-positive ce lls per kg bodyweight (BW). These variables were previous unsuccessful PBSC mobilization trial, previous large held radiotherapy, four or mo re cycles of myelosuppressive chemotherapy regimens, and combinations of extended held radiotherapy plus chemotherapy. Based on these inclus ion criteria we treated 19 patients with disease;specific conventional -dose chemotherapy followed by sequential subcutaneous administration of IL-3 (5 mu g/kg BW) for 5 consecutive days and G-CSF (10 mu g/kg) u ntil PBSC collection or neutrophil recovery. Patients were 10 males an d nine females with a median age of 43 years. Diagnoses were non-Hodgk in's lymphoma n = 5, Hodgkin's disease n = 2, multiple myeloma n = 2, CML n = 4, AML n = 4 and testicular cancer n = 2. Twelve patients had prior unsuccessful trial of PBSC mobilization with chemotherapy follow ed by G-CSF. Except for mobilization chemotherapy-related neutropenic fever, no major toxicities (WHO grade greater than or equal to 2) were observed. Growth factors were well tolerated. Collection of at least 2.5 x 10(6) CD34-positive cells per kg BW was possible in II out of 19 patients (58%). In five out of 12 patients with a previous unsuccessf ul trial of PBSC mobilization, the study regimen mobilized sufficient CD34-positive cells. Nine patients went on to high-dose chemotherapy f ollowed by autologous PBSC transplantation. Prompt hematologic recover y was seen in all of them. In conclusion, the sequential administratio n of IL-3 followed by G-CSF after conventional-dose chemotherapy allow s successful PBSC collection in the majority of extensively pretreated patients.