MOBILIZATION OF PREDOMINANTLY PHILADELPHIA CHROMOSOME-NEGATIVE BLOOD PROGENITORS USING CYCLOPHOSPHAMIDE AND RHUG-CSF IN EARLY CHRONIC-PHASECHRONIC MYELOID-LEUKEMIA - CORRELATION WITH SOKAL PROGNOSTIC INDEX AND HEMATOLOGICAL CONTROL

Mobilization of Philadelphia chromosome (Ph) negative blood progenitor s was attempted in 23 newly diagnosed chronic myeloid leukaemia (CML)) patients using a regimen of cyclophosphamide (CY) 5 g/m(2) and rHUG-C SF 150 mu g/m(2) daily. This regimen was well tolerated with no major adverse events reported. More than 2 x 10(6)/kg CD34(+) cells were col lected in 21 patients (91%). Predominantly Ph-negative mobilization (0 -25% Ph-positive) was seen in 30% of cases overall and was confined to patients with a Sokal prognostic score < 1 (7/11 with Sokal score <1; 0/12 with Sokal score greater than or equal to 1). Within the low Sok al index group, a low WBC count pre-mobilization and a low WBC nadir b oth correlated strongly with Ph-negative mobilization (P = 0 . 006 and 0 . 02 respectively). Five of 19 patients receiving at least 6 months of Roferon A therapy post mobilization achieved a major cytogenetic r esponse; all five patients were Ph-negative mobilizers. Therefore CML patients can be divided into a good-prognosis group in whom predominan tly Ph-negative progenitors can be mobilized using a regimen of modera te intensity if haematological control is achieved pre-mobilization, a nd a poor-prognosis group for whom predominantly Ph-positive cells are mobilized with this regimen regardless of haematological control.