PBSC are the preferred source of stem cells for autologous transplantation. However, regardless of the mobilization procedure used, 10%-20% of patients fail to collect an adequate number to ensure prompt engraftment. There is as yet no standard mobilization procedure for patients who fail a first mobilization attempt. Here, we describe a highly efficient strategy to obtain an adequate number of stem cells for patients who failed a first mobilization attempt. Seventy-four patients with various hematologic malignancies underwent initial mobilization with various regimens including hematopoietic growth factors with or without chemotherapy. In 72% of patients, > or =2 x 10(6) CD34+ stem cells/kg were collected in the initial mobilization attempt, and patients engrafted in a median of 10 days for neutrophils and 12 days for platelets. Eighteen patients failed to mobilize adequate numbers of stem cells, defined as the inability to collect 0.2 x 10(6) CD34+ stem cells/kg/day in the first 2-3 days. These patients had their apheresis halted. Patients were immediately given G-CSF (32 microg/kg/day) for 4 days as a second attempt at mobilization. Eighty-eight percent of these patients achieved the target of > or =2 x 10(6) CD34+ cells/kg, with a median duration of apheresis of 5 days (including the first and second mobilizations). The mean CD34+ cells/kg/day increased after administration of high-dose G-CSF from 0.16 after the first mobilization attempt to 0.61 (p = 0.0002) after the second mobilization. All patients engrafted in a median of 11 and 13 days for neutrophils and platelets, respectively. We conclude that patients whose apheresis yield is <0.4 x 10(6) CD34+ cells/kg after the first two apheresis collections can be successfully mobilized if high-dose G-CSF is administered immediately and continued until achieving > or =2 x 10(6) CD34+ stem cells/kg.

We designed a randomized, prospective three-arm mobilization study to determine the kinetics of peripheral blood stem cell (PBSC) mobilization in 60 non-Hodgkin's lymphoma (NHL) patients primed with cyclophosphamide (CTX) in combination with granulocyte colony-stimulating factor (G-CSF) (arm A), granulocyte-macrophage (GM)-CSF (arm B) or GM-CSF/G-CSF (arm C). We also compared mobilization and transplant-related toxicities, pre- and post-transplant support and the probability of survival among the three arms. To date, 35 patients have been enrolled in the study; 13 patients have been enrolled in arm A, 10 patients in arm B, and 13 patients in arm C. Successful collection of the target of > or = 2 X 10(6) CD34+ cells/kg in one to four apheresis collections was 10/13, 6/10, and 7/12 in arms A, B, and C, respectively. The differences between arms were not statistically significant. The median time to achieve the target CD34+ cells in patients who successfully mobilized the target CD34+ cells was 3 days, 2 days, and 1 day, in patients in arms A, B, and C, respectively. The time for neutrophil engraftment was 11, 10, and 10 days in arms A, B, and C, respectively. The time for platelet engraftment was 11 days for patients in all arms of the study. Most importantly, no significant differences were observed among the three arms in the duration of neutropenic fever, the extent of mucositis, diarrhea, and nausea/vomiting, or in the number of units of platelets or red cells transfused after transplantation. Risk factors associated with poor mobilization were > or = 3 regimens of chemotherapy prior to mobilization, older age, and disease histology (follicular versus diffuse). Therefore, we conclude that the type of growth factor used for mobilization did not play a major role in the outcome of mobilization and recommend mobilizing NHL patients before they receive multiple regimens of chemotherapy.

Summary:Patients undergoing autologous peripheral blood stem cell transplantation (PBSC) frequently require the sequential insertion of two central venous catheters, one for leukapheresis and one for transplant support. Hybrid catheters suitable for leukapheresis and longterm use have been increasingly used, but there is limited information regarding their performance and complication rate. The purpose of this study was to determine the performance of the Pheres-Flow hybrid catheter when utilized for both leukapheresis and transplant support, with particular emphasis on the incidence of infectious and occlusive complications. We prospectively analyzed the performance of 92 catheters in 82 consecutive patients who underwent autologous peripheral blood stem cell (PBSC) transplantation. Occlusion was the most frequent complication of this catheter with 29% of the patients experiencing difficulty drawing blood or infusing fluids. Infection was another frequent complication. Twenty-two percent of patients developed catheter-related bloodstream infections and 15 catheters had to be removed because of proven or suspected infection that did not respond to antibiotic therapy. Nevertheless, 77% of patients were able to complete leukapheresis and transplant support with only one catheter. We conclude that the utilization of the Pheres-Flow catheter for both leukapheresis and transplant support is feasible, but that new strategies need to be developed to decrease the incidence of occlusive and infectious complications of hybrid catheters.