Successful peripheral blood stem cell mobilization with etoposide (VP-16) in patients with relapsed or resistant lymphoma who failed cyclophosphamide mobilization

High-dose chemotherapy (HDCT) followed by autologous blood stem cell transplantation is considered the treatment of choice for patients with relapsed or resistant aggressive non-Hodgkin's lymphoma (NHL) or Hodgkin's disease (HD). However, several authors report failure of standard mobilization regimens in 29% to 56% of these patients making the completion of HDCT impossible and as a result, negatively influencing long-term outcome. Thus, effective new regimens for patients failing initial mobilization are needed. Here we report the results of using etoposide as a mobilizing agent in 16 patients with primary resistant or relapsed malignant lymphoma who had failed prior mobilization of peripheral blood stem cells (PBSC) with cyclophosphamide (4 g/m2) followed by G-CSF. The use of etoposide 500 mg/m2 (days 1-4) + G-CSF resulted in the successful collection of adequate numbers of PBSC with a median harvest of 3.6 x 10(6)/kg (range 2.2-12.6) CD34+ cells in all 16 patients. In 7/16 (44%) patients, the target yield of at least 2.0 x 10(6) CD34+ cells was harvested by a single apheresis and the maximum number of separations for all patients was two. No excessive toxicities appeared, allowing all patients to proceed to myeloablative chemotherapy. In addition, median peak values of circulating CD34+ cells were significantly higher after etoposide as compared to cyclophosphamide (49.2/microl vs 4.7/microl; P = 0.0004). These results indicate that etoposide + G-CSF is a highly effective mobilization regimen in patients who have failed cyclophosphamide mobilization.