Selective overshoot of Ph-negative blood hemopoietic cells after intensive idarubicin-containing regimen and their repopulating capacity after reinfusion.

Twenty-seven patients with chronic myelogenous leukemia (CML)--17 in the chronic phase and 10 in the accelerated phase--were treated with an intensive chemotherapy regimen consisting of idarubicin, arabinosylcytosine, and etoposide. All patients were ineligible for bone marrow transplantation (BMT) and showed little or no cytogenetic response to interferon alpha (IFN-alpha). Blood hemopoietic cells (BHC) were collected by leukapheresis in all patients during early recovery from chemotherapy-induced aplasia. In 13/27 patients (48%), all metaphases were Ph-negative (Ph-); in another five patients, the percentage of Ph-positive (Ph+) metaphases decreased to less than 50%. Complete Ph+ disappearance was found in 66% of the patients treated within two years of diagnosis and in only 30% of those treated later. The collected Ph- cells have been used as autotransplants in nine patients: seven have shown sustained engraftment, and five are alive and well, with Ph- at 3+, 4+, 7+, 11+, and 19+ months after transplant. It is remarkable that one patient, now Ph- at 19 months after transplant, is also PCR negative. These results suggest that it is possible to collect Ph- hemopoietic cells even years after diagnosis and to perform autologous transplants with these cells.