High-dose hydroxyurea plus G-CSF mobilize BCR-ABL-negative progenitor cells (CFC, LTC-IC) into the blood of newly diagnosed CML patients at any time of hematopoietic regeneration.

The objective of this study was to analyze the mobilization kinetics of normal (BCR-ABLneg) and malignant (BCR-ABLpos) progenitor cells using a new, low toxic, out-patient-based mobilization regimen for Philadelphia chromosome-positive (Phpos) chronic myelogenous leukemia (CML) patients. High doses of hydroxyurea (HD-HU, 3.5g/m2 per day, orally for 7 days) followed by granulocyte colony-stimulating factor (G-CSF) (10 μg/kg subcutaneously) were administered to 11 newly diagnosed CML patients. Each apheresis product (n = 30) was individually analyzed for the number and genotype of mature colony-forming cells (CFC) and primitive long-term culture initiating cells (LTC-IC), respectively, by reverse transcription polymerase chain reaction (RT-PCR) of individual colonies. Sufficient numbers of CD34+ cells/kg bodyweight (BW) could easily be obtained in all patients (median, 15 × 106/kg BW per patient) with a median number of three aphereses performed per patient (range 2-4). Almost each apheresis itself (25/30) ...