MOBILIZATION OF PHILADELPHIA-NEGATIVE PERIPHERAL-BLOOD MONONUCLEAR-CELLS IN CHRONIC MYELOID-LEUKEMIA USING HYDROXYUREA AND G-CSF (FILGRASTIM)

A relatively simple and non-toxic out-patient-based regimen for the mo bilization of Philadelphia-negative (Ph - ve) mononuclear cells in chr onic myeloid leukaemia (CML) was evaluated in 10 patients, nine in sta ble chronic phase and one in accelerated phase. They received oral hyd roxyurea at a mean dose of 3.5 g/m(2) daily for 7 d, followed by 300 m u g of G-CSF daily until the last day of harvesting. In the nine chron ic-phase patients the mean number of days from the end of hydroxyurea to the commencement of harvesting was 14.5 (range 10-18). The patient in accelerated phase recovered and was harvested after 6 d. The mean n umber of aphereses performed was 3.4. Adequate numbers of stem cells w ere obtained in 9/10 patients judged by our usual criteria. Side-effec ts were mild in comparison to published intravenous schedules. No pati ents lost their hair. Five (50%) patients required admission with neut ropenic fever which responded to antibiotics in all cases. Four (40%) patients developed a transient rash and four (40%) experienced mild or al mucositis. This level of toxicity enabled half of the patients to b e treated entirely on an out-patient basis. The harvest products were analysed for cells belonging to the leukaemic clone by conventional cy togenetics. FISH and PCR. All were PCR positive. The mean Ph positivit ies by cytogenetics and FISH were comparable at 18.1% and 15% respecti vely. Half the patients had > 98% normal metaphases. We conclude that this approach is comparable in efficacy to published intravenous regim ens and significantly less toxic. It can be safely used at diagnosis b efore interferon therapy commences.