Mobilization of hematopoietic progenitor cells with paclitaxel (taxol) as a single chemotheraupetic agent, associated with rhG-CSF

We assessed the mobilization capacity of taxol with rhG-CSF, both as a sing le chemotherapeutic agent and in the presence of cyclophosphamide (CY), and compared the effect with yields achieved when mobilization was performed s olely with rhG-CSF, Fifteen patients with breast cancer received taxol 170 mg/m(2) (continuous infusion, day 1) and rhG-CSF (8 mu g/kg/day, from day 2 until the end of apheresis) (T-G group), while seven breast cancer patient s were additionally treated with CY (4 g/m(2)) on day 2, followed by rhG-CS F starting at similar doses on day 3 (T-CY-G group), The PBSC collections a fter taxol with/without CY were compared with those of 30 breast cancer pat ients who had received rhG-CSF (8 mu g/kg/day) for mobilization, No differe nces were found in the characteristics of patients included in any of the t hree mobilization groups, The median yield of CD34(+) cells from all patien ts included in taxol containing schedules was 9 x 10(6)/kg (range 2-26) col lected with a median of one apheresis procedure (range 1-4). Leukaphereses began earlier in the T-G group (median day 8, range 7-10) than in the T-CY- G group (median day 13, range 11-17), In most patients (20 out of 22) who r eceived taxol containing regimens, more than 2.5x10(6) CD34(+) cells/kg, a threshold considered to be sufficient for hematopoietic reconstitution, wer e collected with a single apheresis, Those patients in the T-G group experi enced less neutropenic and thrombocytopenic days, with all neutropenic feve r episodes developing in patients treated with the T-CY-G schedule (43%), W hen considering priming with rhG-CSF alone in our historical cohort of 30 b reast cancer patients, a significant detrimental effect was observed in com parison with taxol mobilizing schedules, in the number of aphereses perform ed, in the total yield CD34(+) cells and in the number of patients who achi eved the target dose of 2.5 x 10(6)/kg CD34(+) cells within the first colle ction procedure, We conclude that taxol containing schedules are effective in mobilizing PBSC and facilitate the collection of high yields of CD34(+) cells (usually more than 5x10(6)/kg recipient body weight) with a reduced n umber of apheresis procedures, Taxol, as a single agent with rhG-CSF, exhib its less hematological toxicity than the combination chemotherapy mobilizat ion regimen including CY.