Cyclophosphamide and paclitaxel as initial or salvage regimen for the mobilization of peripheral blood progenitor cells

Peripheral blood progenitor cells are now commonly used for hematologic rec onstitution after myelosuppressive chemotherapy for hematologic and solid m alignancies. The purpose of this study was to evaluate the activity of pacl itaxel 170 mg/m(2) and cyclophosphamide 2 g/m(2) (CF) with filgrastim (huma n G-CSF) for mobilization of PBPCs as the first or second maneuver after fa ilure with filgrastim alone, Sixty-four patients with stage II-IV breast ca ncer received (CP) followed by filgrastim (10 mu g/kg/day), In 35 (55%) thi s was the first maneuver while it was for salvage in 29 (45%) patients, The median number of aphereses was two (range, 1-7), In 83% of the patients ap heresis was initiated on days 10-11 following chemotherapy, The median numb ers of CD34(+) cells/kg, CD34(+) cells/apheresis/kg and total nucleated cel ls/kg collected were 8.7 x 10(6) (2.11-73.5), 3.97 x 10(6) (0.3-36.75) and 164.15 x 10(8) (9-660), respectively. All the patients yielded at least 2 x 10(6) CD34(+) cells/kg, CP mobilization salvaged the 29 patients who faile d mobilization with filgrastim alone. When used as first-line mobiliaation the yield of CD34(+) cells x 10(6)/kg was higher than in the salvage group (16.93 vs 3.94, P < 0.001), Patients receiving CP as salvage reached the ta rget of 5 x 10(6) CD34(+) cells/kg in only 45% (13/29) of cases vs 94.3% as first maneuver. CP followed by filgrastim is a safe and effective regimen for the mobilization of PBPCs in patients with breast cancer and shows sign ificant activity in patients who failed to mobilize with filgrastim, sugges ting a higher mobilization potential.