Peripheral blood progenitor cell collection without close monitoring of peripheral blood CD34+ cells: A feasible strategy for multiple myeloma or pre-treated Non-Hodgkin's Lymphoma patients mobilized with low-dose cyclophosphamide plus G-CSF.

BACKGROUND: Daily monitoring of peripheral blood CD34+ cells may not be necessary for all patients with hematologic malignancies for adequate peripheral blood progenitor cells (PBPC) mobilization and harvesting. We therefore designed a regimen for PBPC mobilization in patients with multiple myeloma or pre-treated Non-Hodgkin's lymphoma based on a combination of low-dose cyclophosphamide (Cy) plus granulocyte colony-stimulating factor (G-CSF) without daily monitoring of peripheral blood CD34+ cells.

STUDY DESIGN AND METHODS: A prospective study was performed on patients with multiple myeloma (n = 22) or pre-treated Non-Hodgkin's lymphoma (n = 17) whose PBPC were harvested according to the following regimen: 1.5 g/m(2) Cy at day 1, 12 microg/kg/day G-CSF from day +7 to +11 avoiding daily monitoring of peripheral blood CD34+ cells and two consecutive leukapheresis at days +12 and +13. The optimum threshold of 2x10(6) CD34+ cells per kg was established.

RESULTS: The proportion of patients with higher CD34+ cell yield after two leukapheresis was similar: multiple myeloma (16/22-72.7%) and Non-Hodgkin's lymphoma (12/17-70.6%). Exposure to radiotherapy and greater than two prior chemotherapy regimens were significantly associated with lower yield in multiple myeloma (p = 0.002) and Non-Hodgkin's lymphoma patients (p = 0.002), respectively.

CONCLUSION: Our data suggested that adequate yields of CD34+ cells may be achieved in multiple myeloma or pre-treated Non-Hodgkin's lymphoma mobilized with low-dose Cy plus G-CSF regardless of the daily monitoring of peripheral blood CD34+ cells.