PERIPHERAL-BLOOD PROGENITOR CELLS MOBILIZED BY CHEMOTHERAPY PLUS GRANULOCYTE-COLONY-STIMULATING FACTOR ACCELERATE BOTH NEUTROPHIL AND PLATELET RECOVERY AFTER HIGH-DOSE VP16, IFOSFAMIDE AND CISPLATIN

We report on the chemotherapy plus granulocyte colony-stimulating fact or (G-CSF) induced mobilization of peripheral blood progenitor cells ( PBPCs) and their impact on haematopoietic recovery following high-dose chemotherapy. Twenty-four patients with advanced solid tumours or lym phomas received standard-dose chemotherapy with VP16, ifosfamide and c isplatin (VIP) followed by filgrastim (G-CSF: 5 mug/kg s.c. daily for 14 d) for the prevention of chemotherapy induced neutropenia and for t he simultaneous mobilization of PBPCs. Maximal numbers of progenitors of different lineages were reached at day 11 (range 9-14) after VIP ch emotherapy. A median of 0.415 x 10(9)/l CD34+ cells (range 0.11-1.98), 9000 CFU-GM/ml (range 2800-17 700), 3 500 BFU-E/ml (range 400-10 800) and 200 CFU-GEMM/ml (range 0-4400) were recruited. One single apheres is yielded a median of 1.6 x 10(8) mononuclear cells/kg (range 0.2-5.4 ) or 5.4 x 10(6) CD34+ cells/kg body weight (range 0.2-24.2). Fourteen patients who showed at least a partial remission after two cycles of the standard-dose chemotherapy regimen were subjected to high-dose VIP chemotherapy (cumulative doses of 1500 mg/m2 VP16,12 g/m2 ifosfamide and 150 mg/m2 cisplatin) with or without PBPC support. The first six p atients were treated with growth factors only (IL-3/GM-CSF) and did no t receive PBPCs, whereas the following eight patients were supported w ith PBPCs in addition to IL-3 and GM-CSF. Neutrophil recovery as well as platelet recovery were significantly faster in patients receiving P BPCs with a median of 6.5 d below 0.1 x 10(9) neutrophils/l and 3 d be low 20 x 10(9) platelets/I as compared to 10.5 d and 8 d in control pa tients receiving growth factors only. The accelerated platelet recover y in patients supported with PBPCs might be explained-in the absence o f detectable colony-forming units megakaryocyte-by the presence of gly coprotein IIb/IIIa+, non-proliferating endomitotic megakaryocytic prec ursor cells within G-CSF mobilized PBPCs. Our data demonstrate that ch emotherapy plus G-CSF mobilized PBPCs accelerate both neutrophil and p latelet recovery after high-dose VIP chemotherapy in patients with sol id tumours or lymphomas.