Impaired PBPC collection in patients with myeloma after high-dose melphalan

Tandem stem cell transplantation is an important treatment option for patients with myeloma and some additional tumors. In an attempt to reduce the contamination of the stem cell graft with tumor cells, patients with myeloma who entered complete remission after the first transplant underwent a second episode of mobilization to obtain progenitor cells for the second transplant. Twenty-two patients with myeloma participated in the study. The first mobilization utilized CY, etoposide and filgrastim. The second mobilization used the same regimen, but seven patients received only filgrastim. The interval between the two collection periods was 6 months (median; range 4–9 months). The preparative regimen for the first transplant consisted of melphalan 200mg/m2. The number of total white cells collected during the two collection episodes was similar: 10.8±1.6×108/kg white cells vs. 11.8±1.7×108/kg white cells (P=0.63). The collected CD34+ cell dose was much larger during the first collection: 45.2±8.4×106/kg vs. 6.9±2.7×106/kg (P