Remobilization of patients who fail to achieve minimal progenitor thresholds at the first attempt is clinically worthwhile.

A significant proportion of previously treated patients fail to mobilize sufficient stem/progenitor cells to enable high-dose therapy and peripheral blood stem cell transplantation to be performed. In this study, the value of remobilizing such patients has been evaluated in 20 patients who all failed to achieve progenitor yields of 1 x 10(6)/kg CD34+ cells and 1 x 10(5)/kg granulocyte-monocyte colony-forming units (GM-CFCs) at the first attempt. Most patients remained relatively poor mobilizers at the second mobilization, but the yield of CD34+ cells and GM-CFCs on the first apheresis was significantly greater with the second mobilization than the first. A total yield (all aphereses from both mobilizations) of > 1 x 10(6)/kg CD34+ cells and > 1 x 10(5)/kg GM-CFCs was achieved in 14 out of 20 patients. Seven patients have received high-dose therapy with stem cell infusion; neutrophil recovery was rapid in all patients and platelet independence occurred in < 21 d in five out of seven patients. We conclude that remobilization is worth considering in those patients in whom a chemotherapy-free interval of several months is possible.