Ten consecutive patients in our unit who had failed to mobilize a sufficient stem cell yield after either an initial or several mobilization regimens received high-dose etoposide phosphate (1500-2000 mg/m2) followed by granulocyte colony-stimulating factor (G-CSF; 10 micrograms/kg per day) to stimulate mobilization. Eight of the ten patients were apheresed. A median of 2.1 x 10(6) CD34+/kg (range 0-5.2) was collected. The number of CD34+ cells/microliter peripheral blood (pB) was significantly increased compared to the first-line mobilization [median 13.0 (range 2.68-29) versus median 4.76 (range 1.36-12); P < 0.05]. Besides hematotoxicity and four cases of infection (WHO grade 3), no major side effects were seen. The median duration of neutropenia was short (5 days, range 0-10), which is important in heavily pretreated patients. These results indicate that high-dose etoposide phosphate with G-CSF is safe, well tolerated, and may be effective in peripheral blood stem cell (PBSC) mobilization in patients who had previously failed to mobilize.