Poor hematopoietic stem cell mobilizers in multiple myeloma: a single institution experience

In a single institution, in a group of 28 myeloma patients deemed eligible for autologous transplant, stem cell mobilization was attempted using filgrastim: 26 individuals were given 31 autografts employing 1-4 (median three) apheresis sessions, to obtain a target stem cell dose of 1 x 10(6) CD34 +ve viable cells / Kg of the recipient. The median number of grafted CD34 cells was 7.56 x 10(6) / Kg of the recipient; the range being 0.92 to 14.8. By defining as poor mobilizers individuals in which a cell collection of < 1 x 10(6) CD34 viable cells / Kg was obtained, a subset of eight poor mobilizers was identified; in two patients the autograft was aborted because of an extremely poor CD34 +ve cell yield (< 0.2 x 10(6) CD34 +ve viable cells / Kg of the recipient) after four apheresis sessions. The long-term overall survival of the patients grafted with > 1 x 10(6) CD34 +ve viable cells / Kg was better (80% at 80 months) than those grafted with < 1 x 10(6) CD34 +ve viable cells / Kg (67% at 76 months). Methods to improve stem cell mobilization are needed and may result in obtaining better results when autografting multiple myeloma patients.