Poor Hematopoietic Stem Cell Mobilizers in Multiple Myeloma:A Single Institution Experience.

Abstract 4237

High-dose chemotherapy rescued by autologous peripheral blood stem cell transplantation is considered standard of care for patients with multiple myeloma. Hematopoietic stem cell mobilization is accomplished by administration of hematopoietic growth factors combined or not with myelosuppressive chemotherapy. In a single institution, in a group of twenty eight myeloma patients deemed eligible for autologous transplant, stem cell mobilization was attempted using only filgrastim: Twenty six individuals were given 31 autografts employing one to four (median three) apheresis sessions, to obtain a target stem cell dose of 1 × 10⁶ CD34 viable cells / Kg of the recipient. The median number of grafted cells was 7.56 × 10⁶ CD34 viable cells / Kg of the recipient; the range being 0.92 to 14.8. By defining as poor mobilizers individuals in which a cell collection of less than 1 × 10⁶ 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 cell yield (less than 0.2 × 10⁶ CD34 viable cells / Kg of the recipient) after four apheresis sessions. The long-term overall survival of the patients grafted with more than 1 × 10⁶ CD34 viable cells / Kg was better (80% at 80 months) than those grafted with less than 1 × 10⁶ CD34 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.