Ifosfamide in combination with paclitaxel or doxorubicin: regimens which effectively mobilize peripheral blood progenitor cells while demonstrating anti-tumor activity in patients with metastatic breast cancer

For patients with metastatic breast cancer (MBC) who undergo high-dose therapy with autologous peripheral blood progenitor cell (PBPC) transplantation, an important prerequisite is a mobilization regimen that efficiently mobilizes PBPCs while producing an effective anti-tumor effect. We prospectively evaluated ifosfamide-based chemotherapy for mobilization efficiency, toxicity and disease response in 37 patients. Patients received two cycles of the ifosfamide-based regimen; ifosfamide (5 g/m2 with conventional-dose cycle and 6 g/m2 with mobilization cycle) with either 50 mg/m2 doxorubicin (if limited prior anthracycline and/or progression more than 12 months after an anthracycline-based regimen) or 175 mg/m2 paclitaxel. For the mobilization cycle, all patients received additional G-CSF (10 microg/kg SC, daily) commencing 24 h after completion of chemotherapy. The target yield was >6x10(6) CD34+ cells/kg, sufficient to support the subsequent three cycles of high-dose therapy. The mobilization therapy was well tolerated and the peak days for peripheral blood (PB) CD34+ cells were days 10-13 with no significant differences in the PB CD34+ cells mobilization kinetics between the ifosfamide-doxorubicin vs. ifosfamide-paclitaxel regimens. The median PBPC CD34+ cell content ranged from 2.9 to 4.0x10(6)/kg per day during days 9-14. After a median of 3 (range 1-5) collection days, the median total CD34+ cell, CFU-GM and MNC for all 44 individual sets of collections was 9.2x10(6)/kg (range 0.16-54.9), 37x10(4)/kg (range 5.7-247) and 7.3x10(8)/kg (range 2.1-26.1), respectively. The PBPC target yield was achieved in 35 of the 37 patients. The overall response rate for the 31 evaluable patients was 68% with 10% having progressive disease. Thirty-three patients have subsequently received high-dose therapy consisting of three planned cycles of high-dose ifosfamide, thiotepa and paclitaxel with each cycle supported with PBPCs. Rapid neutrophil and platelet recovery has been observed. Ifosfamide with G-CSF in combination with doxorubicin or paclitaxel achieves effective mobilization of PBPC and anti-tumor activity with minimal toxicity.     

Mobilization of peripheral blood progenitor cells (PBPC) in patients undergoing chemotherapy followed by autologous peripheral blood stem cell transplant (SCT) for high risk breast cancer (HRBC).

We have determined the effect of delayed addition of G-CSF after chemotherapy on PBPC mobilization in a group of 30 patients with high risk breast cancer (HRBC) undergoing standard chemotherapy followed by high-dose chemotherapy (HDCT) and autologous SCT. Patients received FAC chemotherapy every 21 days followed by G-CSF at doses of 5 microg/kg/day starting on day +15 (groups 1 and 2) or +8 (group 3) after chemotherapy. PBPC collections were performed daily starting after 4 doses of G-CSF and continued until more than 2.5 x 10(6) CD34+ cells had been collected. In group 1, steady-state BM progenitors were also harvested and used for SCT. Groups 2 and 3 received PBPC only. The median number of collections was three in each group. Significantly more PB CD34+ cells were collected in patients receiving G-CSF starting on day 8 vs day 15 (9.43 x 10(6)/kg and 6.2 x 10(6)/kg, respectively) (P < 0.05). After conditioning chemotherapy all harvested cells including BM and PBPC were reinfused. Neutrophil and platelet engraftment was significantly faster in patients transplanted with day 8 G-CSF-mobilized PBPC (P < 0.05) and was associated with lower transplant related morbidity as reflected by days of fever, antibiotics or hospitalization (P < 0.05). Both schedules of mobilization provided successful long-term engraftment with 1 year post-transplant counts above 80% of pretransplant values. In conclusion, we demonstrate that delayed addition of G-CSF results in successful mobilization and collection of PBPC with significant advantage of day 8 G-CSF vs day 15. PBPC collections can be scheduled on a fixed day instead of being guided by the PB counts which provides a practical advantage. Transplantation of such progenitors results in rapid short-term and long-term trilineage engraftment.     

An analysis of engraftment kinetics as a function of the CD34 content of peripheral blood progenitor cell collections in 692 patients after the administration of myeloablative chemotherapy

The CD34 antigen is expressed by committed and uncommitted hematopoietic progenitor cells and is increasingly used to assess stem cell content of peripheral blood progenitor cell (PBPC) collections. Quantitative CD34 expression in PBPC collections has been suggested to correlate with engraftment kinetics of PBPCs infused after myeloablative therapy. We analyzed the engraftment kinetics as a function of CD34 content in 692 patients treated with high-dose chemotherapy (HDC). Patients had PBPCs collected after cyclophosphamide based mobilization chemotherapy with or without recombinant human granulocyte colony-stimulating factor (rhG-CSF) until > or = 2.5 x 10(6) CD34+ cells/kg were harvested. Measurement of the CD34 content of PBPC collections was performed daily by a central reference laboratory using a single technique of CD34 analysis. Forty-five patients required a second mobilization procedure to achieve > or = 2.5 x 10(6) CD34+ cells/kg and 15 patients with less than 2.5 x 10(6) CD34+ cells/kg available for infusion received HDC. A median of 9.94 x 10(6) CD34+ cells/kg (range, 0.5 to 112.6 x 10(6) CD34+ cells/kg) contained in the PBPC collections was subsequently infused into patients after the administration of HDC. Engraftment was rapid with patients requiring a median of 9 days (range, 5 to 38 days) to achieve a neutrophil count of 0.5 x 10(9)/L and a median of 9 days (range, 4 to 53+ days) to achieve a platelet count of > or = 20 x 10(9)/L. A clear dose-response relationship was evident between the number of CD34+ cells per kilogram infused between the number of CD34+ cells per kilogram infused and neutrophil and platelet engraftment kinetics. Factors potentially influencing the engraftment kinetics of neutrophil and platelet recovery were examined using a Cox regression model. The single most powerful mediator of both platelet (P = .0001) and neutrophil (P = .0001) recovery was the CD34 content of the PBPC product. Administration of a post-PBPC infusion myeloid growth factor was also highly correlated with neutrophil recovery (P = .0001). Patients receiving high-dose cyclophosphamide, thiotepa, and carboplatin had more rapid platelet recovery than patients receiving other regimens (P = .006), and patients requiring 2 mobilization procedures versus 1 mobilization procedure to achieve > or = 2.5 x 10(6) CD34+ cells/kg experienced slower platelet recovery (P = .005). Although a minimal threshold CD34 dose could not be defined, > or = 5.0 x 10(6) CD34+ cells/kg appears to be optimal for ensuring rapid neutrophil and platelet recovery.     

Potentiation of granulocyte colony-stimulating factor-induced mobilization of circulating progenitor cells by seven-day pretreatment with interleukin-3

Granulocyte colony-stimulating factor (G-CSF) as a single agent is increasingly used for the mobilization of peripheral blood progenitor cells (PBPCs) for stem cell transplantation. In patients with perturbed hematopoiesis the mobilizing capacity of G-CSF alone may be inadequate. We have shown in rhesus monkeys that interleukin-3 (IL-3) pretreatment markedly potentiated the increase in PBPC numbers by subsequent administration of granulocyte/macrophage-CSF (GM-CSF). Here we studied the effect of IL-3 pretreatment on G-CSF-induced mobilization of PBPCs in 6 patients with Hodgkin's disease (n = 5) or non-Hodgkin's lymphoma (n = 1) who had low progenitor cell numbers because of previous chemotherapy. Patients were treated in cycle 1 with G-CSF at a dose of 5 microgram/kg/d for 5 days and, after a treatment-free interval, received cycle 2 consisting of 5 microgram/kg/d of IL-3 for 7 days followed by G-CSF again at a dose of 5 microgram/kg/d for 5 days. G-CSF alone increased the mean number of circulating colony-forming units-GM (CFU-GM) by 21-fold, the number of burst-forming units-erythroid (BFU- E) by 9-fold, and the number of CFU-mix by 24-fold over pretreatment values. Treatment with 5 microgram/kg/d of IL-3 for 7 days did not mobilize by itself but significantly potentiated G-CSF-induced mobilization of all progenitor cell types leading to a 56-, 15-, and 46- fold increase over baseline of CFU-GM, BFU-E, and CFU-mix numbers, respectively. In 2 patients in whom leukapheresis was performed after G- CSF alone the target number of 2 x 10(6)/kg CD34+ cells was not reached. However, leukapheresis after the IL-3/G-CSF combination obtained > or =2 x 10(6)/kg CD34+ cells in 3 of 6 patients, including both patients who had inadequate collection after G-CSF alone. In one patient adequate function of mobilized progenitors could be shown by the demonstration of rapid trilineage engraftment after infusion of progenitors after myeloablative chemotherapy. Seven-day pretreatment with IL-3 may be a useful mean to augment mobilization of circulating progenitors by G-CSF. The combination of IL-3 and G-CSF seems to allow the procurement of sufficient numbers of PBPCs in some patients who cannot be mobilized adequately by G-CSF alone.     

Etoposide (VP-16) plus G-CSF mobilizes different dendritic cell subsets than does G-CSF alone

Dendritic cells (DCs) are antigen-presenting cells that are critical to the generation of immunologic tumor responses. Myeloid DCs (DC1) express myeloid antigen CD11c; lymphoid DCs (DC2) express CD123(+) and are CD11c(-). Analysis of DC subsets from peripheral blood progenitor cells (PBPC) collected from normal donors mobilized with G-CSF shows a predominance of DC2 cells. Whether PBPCs mobilization by chemotherapy yields different subsets of DCs has not been studied. We analyzed DC subsets in apheresis products from 44 patients undergoing autologous stem cell transplantation from 6/00 to 5/01. Patients received either G-CSF alone (10 microg/kg per day, n=11) or etoposide (2 g/m(2)) plus G-CSF (n=33) for progenitor cell mobilization. The patients were apheresed for 2-10 days (median 3) to reach a minimum of 2.0 x 10(6) CD34(+) cells/kg. Patients receiving G-CSF alone mobilized significantly more total DC2s than did those receiving etoposide plus G-CSF (median 6.2 x 10(6)/kg vs 2.9 x 10(6)/kg, P=0.001). The DC2/DC1 ratio was also significantly different in the two groups, with the G-CSF group having a higher ratio (median 1.2 vs 0.4, P<0.001). We conclude that the combination of chemotherapy plus G-CSF yields different mobilized dendritic cell subsets than does G-CSF alone.     

Selection and expansion of peripheral blood CD34+ cells in autologous stem cell transplantation for breast cancer

Cytopenia after high-dose chemotherapy and autologous stem cell reinfusion is a major cause of morbidity. Ex vivo cultured expansion and differentiation of CD34+ peripheral blood progenitor cells (PBPC) to neutrophil precursors may shorten the neutropenic period further. We explored the use of these ex vivo cultured PBPCs in nine patients with metastatic breast cancer. All underwent PBPC mobilization with cyclophosphamide, VP-16, and G-CSF. Subsequently, they underwent four to five apheresis procedures. One apheresis product from each patient was prepared using the Isolex 300 Magnetic Cell Separation System (Baxter Immunotherapy, Irvine, CA) to obtain CD34+ cells. These cells were then cultured in gas permeable bags containing serum-free X-VIVO 10 (BioWhittaker, Walkersville, MD) medium supplemented with 1% human serum albumin and 100 ng/mL PIXY321. At day 12 of culture the mean fold expansion was 26x with a range of 6 to 64x. One patient's cells did not expand because of a technical difficulty. The final cell product contained an average of 29.3% CD15+ neutrophil precursors with a range of 18.5% to 48.1%. The patients underwent high-dose chemotherapy with cyclophosphamide, carboplatin, and thiotepa. On day 0, the cryopreserved PBPCs were reinfused and on day +1 the 12-day cultured cells were washed, resuspended, and reinfused into eight of nine patients. One patient was not infused with cultured cells. The mean number of cultured cells reinfused was 44.6 x 10(6) cells/kg with a range of 0.8 to 156.6 x 10(6) cells/kg. No toxicity was observed after reinfusion. The eight patients have recovered absolute neutrophil counts > 500/microL on a median of 8 days (range 8 to 10 days); the median platelet transfusion independence occurred on day 10 (range 8 to 12 days) and platelet counts > 50,000/microL were achieved by day 12 (range 9 to 14) for the seven patients whose platelet counts could be determined. Expanded CD34+ selected PBPC can be obtained and safely reinfused into patients.     

Peripheral blood progenitor cell collections in cancer patients: analysis of factors affecting the yields

BACKGROUND AND OBJECTIVE: Peripheral blood progenitor cells (PBPC) are now widely used to restore hematopoiesis following high dose chemotherapy in patients with malignancies. We sought to identify parameters that could predict the yield of PBPC after mobilization with chemotherapy (CT) with or without granulocyte colony-stimulating factor (G-CSF) in cancer patients. DESIGN AND METHODS: One hundred and fifty patients underwent 627 PBPC collections during the recovery phase following CT with (n = 469) or without (n = 142) G-CSF. Hemogram, CFC-assays and CD34+ cell count were performed on peripheral blood and leukaphereses products. After log transformation of the data, differences between groups were assessed with the unpaired t-test or one-way analysis of variance. RESULTS: Seventeen and two patients required 2 and 3 mobilization cycles respectively to reach our target of 15x10(4) CFU-GM/kg. In patients with lymphoma but not in those with leukemia, the yields of both CFU-GM and CD34+ cells/kg were dramatically increased when G-CSF was added to CT for mobilization. In collections primed with CT and G-CSF, better yields were obtained in patients with breast cancer or small-cell lung carcinoma (SCLC) as opposed to other solid tumors and leukemia. Among potential predictive factors of CT- and G-CSF-primed harvests, we found that the CD34+ cell count in peripheral blood (PB) was strongly correlated with both the CFU-GM and CD34+ cell yields. Except in leukemia patients, more than 1x10(6) CD34+ cells/kg were harvested when the CD34+ cell count in blood was above 20x10(6)/L. Similarly, better results were obtained in collections performed when the percentage of myeloid progenitors in blood on the day of apheresis was above 5 % or when the leukocyte count in blood was above 5x10(9)/L. INTERPRETATION AND CONCLUSIONS: A diagnosis of breast cancer or SCLC, a leukocyte count in PB of more than 5x10(9)/L, more than 5% myeloid progenitors or more than 20x10(6) CD34+ cells/L in PB were associated with higher yields of PBPC in collections mobilized with CT+G-CSF.     

Effects of short-term administration of G-CSF (filgrastim) on bone marrow progenitor cells: analysis of serial marrow samples from normal donors

To determine the effect of G-CSF administration on both the total number of CD34+ cells and the primitive CD34+ subsets in bone marrow (BM), we have analyzed BM samples serially obtained from 10 normal donors in steady-state and during G-CSF treatment. Filgrastim was administered subcutaneously at a dosage of 10 microg/kg/day (n = 7) or 10 microg/kg/12 h (n = 3) for 4 consecutive days. Peripheral blood sampling and BM aspirates were performed on day 1 (just before G-CSF administration), day 3 (after 2 days of G-CSF), and day 5 (after 4 days of G-CSF). During G-CSF administration, a significant increase in the total number of BM nucleated cells was observed. The percentage (range) of CD34+ cells decreased in BM from a median of 0.88 (0.47-1.44) on day 1 to 0.57 (0.32-1.87), and to 0.42 (0.16-0.87) on days 3 and 5, respectively. We observed a slight increase in the total number of BM CD34+ cells on day 3 (0.66 x 10(9)/l (0.13-0.77)), and a decrease on day 5 (0.23 x 10(9)/l (0.06-1.23)) as compared with steady-state (0.40 x 10(9)/l (0.06-1.68)). The proportion of primitive BM hematopoietic progenitor cells (CD34+CD38-, CD34+HLA-DR-, CD34+CD117-) decreased during G-CSF administration. In parallel, a significant increase in the total number of CD34+ cells in peripheral blood was observed, achieving the maximum value on day 5. These results suggest that in normal subjects the administration of G-CSF for 5 days may reduce the number of progenitor cells in BM, particularly the most primitive ones.     

Very large amounts of peripheral blood progenitor cells eliminate severe thrombocytopenia after high-dose melphalan in advanced breast cancer patients

We analyzed the relationship between the reinfusion of large or very large amounts of peripheral blood progenitor cells (PBPC) and hematologic toxicity in twenty-one advanced breast cancer patients subjected to a myeloablative dose of melphalan at the end of a high-dose sequential chemotherapy (HDSC) program. We also evaluated the influence of the white blood cell (WBC) count to predict an optimal PBPC harvest after high-dose chemotherapy and growth factor priming. Twenty-one patients with high-risk or metastatic breast cancer sequentially received: high-dose cyclophosphamide (HD-Cy) and G-CSF followed by PBPC harvest, HD-methotrexate plus vincristine, HD-doxorubicin, cisplatin and finally HD-melphalan 200 mg/m2 (HD-L-PAM) followed by PBPC reinfusion. No growth factor was administered after HD-L-PAM. CD34+ cytofluorimetric analysis, WBC count and clonogenic assays were employed to monitor circulating cells and to analyze the PBPC harvest. Correlation between different PBPC doses and hematologic toxicity as well as leukocyte and platelet recovery time was attempted. Patients received a median number of 16 (4-25.1) x 10(6)/kg CD34+ cells, 81.3 (30.8-228) x 10(4)/kg CFU-GM and 4.2 (1.3-7.3) x 10(8)/kg nucleated cells (NC) after HD-L-PAM. The number of days with fewer than 1 x 10(9)/l leukocytes and 20 x 10(9)/l platelets were 6 (range 4-9) and 0 (range 0-3), respectively. The CD34+ cell dose significantly correlated with both platelet count nadir (r = 0.73) and time to 50 x 10(9)/l platelets (r = 0.7), but did not correlate with time to reach more than 1 x 10(9)/l WBC count (r = 0.2). In particular, we found that in 12 patients given very large amounts of CD34+ cells, ranging between 15.8 and 25. 1 x 10(6)/kg (V-LA-CD34+), the platelet nadir count never fell below 20 x 10(9)/l and platelet transfusions were not required. Conversely, nine patients who received only large amounts of CD34+ cells, ranging between 4 and 12 x 10(6)/kg (LA-CD34+), experienced a platelet nadir lower than 20 x 10(9)/l and required 2 days (range 1-4) to achieve independence from platelet transfusions (P = 0.001 and P = 0. 0005). The requirement for packed red blood cells (RBC) was 1.5 vs 3 units in the V-LA-CD34+ and LA-CD34+ groups respectively (P = 0.063). The analysis of 44 PBPC collections demonstrated that 29 aphereses performed with a WBC count <20 x 10(9)/l yielded a mean of 312 +/- 43 x 10(6) CD34+ cells and 1831 +/- 201 x 10(4) CFU-GM, whereas 15 collections performed with WBC count >20 x 10(9)/l yielded 553 +/- 64 x 10(6) CD34+ cells and 3190 +/- 432 x 10(4) CFU-GM (P = 0.004). In conclusion, our data suggests that V-LA-CD34+ eliminates severe thrombocytopenia and platelet transfusion requirements in breast cancer patients subjected to HD-L-PAM, and higher PBPC collections seems to coincide with WBC count higher than 20 x 10(9)/l after HD-Cy and G-CSF mobilization. These results justify a prospective study to establish whether large doses of CD34+ cells result in significant clinical benefits.     

Cyclophosphamide and paclitaxel as initial or salvage regimen for the mobilization of peripheral blood progenitor cells

Peripheral blood progenitor cells are now commonly used for hematologic reconstitution after myelosuppressive chemotherapy for hematologic and solid malignancies. The purpose of this study was to evaluate the activity of paclitaxel 170 mg/m2 and cyclophosphamide 2 g/m2 (CP) with filgrastim (human G-CSF) for mobilization of PBPCs as the first or second maneuver after failure with filgrastim alone. Sixty-four patients with stage II-IV breast cancer received (CP) followed by filgrastim (10 microg/kg/day). In 35 (55%) this was the first maneuver while it was for salvage in 29 (45%) patients. The median number of aphereses was two (range, 1-7). In 83% of the patients apheresis was initiated on days 10-11 following chemotherapy. The median numbers of CD34+ cells/kg, CD34+ cells/apheresis/kg and total nucleated cells/kg collected were 8.7 x 10(6) (2.11-73.5), 3.97 x 10(6) (0.3-36.75) and 164.15 x 10(8) (9-660), respectively. All the patients yielded at least 2 x 10(6) CD34+ cells/kg. CP mobilization salvaged the 29 patients who failed mobilization with filgrastim alone. When used as first-line mobilization the yield of CD34+ cells x 10(6)/kg was higher than in the salvage group (16.93 vs 3.94, P < 0.001). Patients receiving CP as salvage reached the target of 5 x 10(6) CD34+ cells/kg in only 45% (13/29) of cases vs 94.3% as first maneuver. CP followed by filgrastim is a safe and effective regimen for the mobilization of PBPCs in patients with breast cancer and shows significant activity in patients who failed to mobilize with filgrastim, suggesting a higher mobilization potential.     

Phenotypic and functional characterization of long-term culture- initiating cells present in peripheral blood progenitor collections of normal donors treated with granulocyte colony-stimulating factor

Granulocyte colony-stimulating factor (G-CSF) mobilized peripheral blood progenitor cells (PBPC) have successfully been used as stem cells for both autologous and allogeneic transplants. However, little is known concerning the absolute number and phenotype of primitive progenitors, such as long-term culture-initiating cells (LTC-IC) in mobilized PBPC. The aim of our study was to evaluate the capacity of G- CSF to mobilize LTC-IC in the PB of normal individuals and to evaluate the phenotypic and functional characteristics of G-CSF mobilized LTC- IC. G-CSF was administered to 29 healthy volunteers at 7.5 micrograms or 10 micrograms/kg/d subcutaneously (SC) for 5 consecutive days and PBPC were harvested on day 6. Mobilization with G-CSF increased the absolute number of week 5 LTC-IC in PB 60-fold, while the number of CD34+ cells and committed colony forming cells (CFC) was increased sevenfold to 12-fold. The frequency of CFC and week 5 LTC-IC in CD34+ cells selected by fluorescence-activated cell sorter (FACS) from mobilized PBPC was 2 +/- 0.3-fold and 9 +/- 2.2-fold higher respectively than in CD34+ cells selected from unmobilized PBMNC. CFC were enriched in the CD34+ CD38+ and CD34+ HLA-DR+ populations. The absolute number of LTC-IC present in CD34+ CD38- and CD34+ HLA-DR- cells selected by FACS from either mobilized PBPC, unmobilized PBMNC or steady state bone marrow (BM) was similar (0.5% to 2%). In contrast to unmobilized PBMNC or steady state BM CD34+ CD38+ and CD34+ HLA-DR+ cells, which contain less than 0.1% LTC-IC, CD34+ CD38+ and CD34+ HLA- DR+ cells sorted from mobilized PBPC contained 0.5% to 5% of cells capable of sustaining hematopoiesis in long-term cultures for 5 weeks. However, 90% to 95% of LTC-IC present in mobilized CD34+ CD38+ and CD34+ HLA-DR+ cells were not able to sustain hematopoiesis for 8 weeks, while 30% of CD34+ CD38- and CD34+ HLA-DR- LTC-IC present in mobilized PBPC could sustain hematopoiesis for at least 8 weeks. This suggests that the majority of CD34+ CD38+ and CD34+ HLA-DR+ week 5 LTC-IC represent progenitors at an intermediate state of differentiation. We conclude that G-CSF effectively mobilizes LTC-IC in the blood of normal individuals. Although a fraction of these cells has functional characteristics similar to those of steady state PBMNC or BM LTC-IC, more than 85% of mobilized PBPC LTC-IC are CD34+ CD38+ and CD34+ HLA- DR+, capable of sustaining hematopoiesis for 5 weeks, but not for 8 weeks. The functional and phenotypic characterization of primitive and more mature populations of LTC-IC in mobilized PBPC should prove extremely useful in future studies examining the role of these progenitors in engraftment following transplantation.     

Transplantation of CD34+ peripheral blood progenitor cells after high- dose chemotherapy for patients with advanced multiple myeloma

A major potential problem of autologous transplantation in the treatment of advanced malignancy is the infusion of tumor cells. A multi-institutional study of purified CD34-selected peripheral blood progenitor cell (PBPC) transplantation was conducted in 37 patients with advanced multiple myeloma receiving myeloablative chemotherapy. Fourteen days after intermediate-dose cyclophosphamide, prednisone, and granulocyte colony-stimulating factor (G-CSF), a median of 3 (range, 2 to 5) 10-L leukaphereses yielded 9.8 x 10(8)/kg (range, 3.7 to 28.3) mononuclear cells. The adsorbed (column-bound) fraction contained 5.9 x 10(6) cells/kg (range, 1.6 to 25.5) with 4.65 x 10(6) CD34 cells/kg (range, 1.2 to 23.3). Using Poisson distribution analysis of positive polymerase chain reactions with patient-specific complementarity- determining region 1 (CDR1) and CDR3 Ig-gene primers, tumor was detected in leukapheresis products from 8 to 14 unselected patients and ranged from 1.13 x 10(4) to 2.14 x 10(6) malignant cells/kg. After CD34 selection, residual tumor was detected in only three patients' products. Overall, a greater than 2.7- to 4.5-log reduction in contaminating multiple myeloma cells was achieved. CD34 PBPCs were infused 1 day after busulfan (14 mg/kg) and cyclophosphamide (120 mg/kg), and granulocyte-macrophage colony-stimulating factor was used until hematologic recovery. The median time to both neutrophil and platelet recovery was 12 days (range, 11 to 16 days and 9 to 52 days, respectively). The median number of erythrocyte and platelet transfusions was 7 (range, 2 to 37) and 3 (range, 0 to 85), respectively. Patients receiving fewer than 2 x 10(6) CD34 cells/kg had significantly prolonged neutropenia, thrombocytopenia, and an increased red blood cell and platelet transfusion requirement. Thus, CD34 selection of PBPCs markedly reduces tumor contamination in multiple myeloma and provides effective hematopoietic support for patients receiving myeloablative therapy.     

Stem cell mobilization with G-CSF alone in breast cancer patients: higher progenitor cell yield by delivering divided doses (2 x 5 microg/kg) compared to a single dose (1 x 10 microg/kg)

We investigated the schedule dependency of G-CSF (10 microg/kg) alone in mobilizing peripheral blood progenitor cells (PBPC) in breast cancer patients. After a median of three cycles (range, 2-6) of anthracycline-based chemotherapy, 49 patients with breast cancer (stage II/III, > or = 10+ Ln n = 36; locally advanced/inflammatory n = 8, stage IV (NED) n = 5) underwent PBPC collection after steady-state mobilization either with 1 x 10 microg/kg (n = 27) or with 2 x 5 microg/kg (n = 22) G-CSF daily for 4 consecutive days until completion of apheresis. Apheresis was started on day 5. Priming with 2 x 5 microg/kg resulted in a higher median number of CD34+ cells (5.8 vs 1.9 x 10(6)/kg, P = 0.003), MNC (6.6 vs 2.6 x 10(8)/kg, P < 0.001) and CFU-GM (6.5 vs 1.3 x 10(4)/kg, P = 0.001) in the first apheresis than with 1 x 10 microg/kg. Also the overall number of collected BFU-E was higher in the 2 x 5 microg group (9.2 vs 3.1 x 10(4)/kg; P = 0.01). After high-dose chemotherapy with cyclophosphamide/thiotepa/mitoxantrone (n = 46) hematopoietic engraftment with leukocyte count > 1.0/nl was reached in both groups after a median of 10 days (range, 8-15) and with platelets count > 50/nl after 12 (range, 9-40) and 13 days (range, 12-41), respectively. A threshold of > 2.5 x 10(6)/kg reinfused CD34+ cells ensured rapid platelet engraftment (12 vs 17 days; P = 0.12). Therefore, the target of collecting > 2.5 x 10(6) CD34+ cells was achieved in 21/27 (80%) patients of the 1 x 10 microg group and in 21/22 (95%) patients of the 2 x 5 microg/kg group with a median of two aphereses (range, 1-4). None in the 10 microg/kg group, but 6/22 (28%) patients in the 2 x 5 microg/kg group required only one apheresis procedure, resulting in fewer apheresis procedures in the 2 x 5 microg/kg group (mean, 1.8 vs 2.3, P = 0.01). These results demonstrate that priming with 10 microg/kg G-CSF alone is well tolerated and effective in mobilizing sufficient numbers of CD34+ cells in breast cancer patients and provide prompt engraftment after CTM high-dose chemotherapy. G-CSF given 5 microg/kg twice daily (2 x 5 microg) leads to a higher harvest of CD34+ cells and required fewer apheresis procedures than when given 10 microg/kg once daily (1 x 10 microg).     

G-CSF-mobilized peripheral blood progenitor cells for allogeneic transplantation: safety,kinetics of mobilization,and composition of the graft

Allogeneic transplantation of peripheral blood progenitor cells (PBPC) markes the general anaesthesia of the donor unnecessary and may result in more rapid engraftment and faster recovery of the immune system. We have studied G-CSF-mediated PBPC mobilization in healthy donors and analysed the cellular composition of the resulting PBPC grafts. PBPC grafts were obtained from nine healthy donors (18-67 years old) for allogeneic or syngeneic transplantation. Six donors received 10 μg/kg G-CSF per day, the others 5-6 μg/kg. Mobilization and harvesting were well tolerated except for moderate bone pain which occurred in all donors primed with 10 μg/kg. With 10 μg/kg, a 31-fold (9-62) enrichment of circulating CD34⁺ cells was observed with peak values constantly occurring on day 5 after the start of G-CSF administration. Starting harvest on day 5, one to three collections on consecutive days yielded 5.5 x 10⁶/kg (0.9-10.7) CD34⁺ cells, 219 x 10⁶/kg (106–314) T cells, and 34 x 10⁶/kg (23–67) NK cells per 10 litres leukapheresis volume. Altogether, PBPC grafts contained 3 times more CD34⁺ cells, 7 times more T cells, and 20 times more NK cells than five allogeneic marrow grafts that were analysed for comparison. The yield of CD34⁺ cells per 10 litres apheresis volume as well as the height of the CD34⁺ peak in peripheral blood were inversely correlated to the age of the donor. In the donors primed with 5–6μg/kg G-CSF the increase of circulating CD34⁺ cells (4–7-fold enrichment) and the CD34⁺ cell yield per 10 litres leukapheresis volume (1 x 10⁶/kg [0.8-2-2]) was much smaller compared with the 10μg/kg group. In conclusion, sufficient amounts of PBPC capable of restoring haemopoiesis in allogeneic recipients can be mobilized safely by administration of G-CSF (10 μg/kg s.c. for 5 d) in healthy donors, and harvested with one or two leukapheresis procedures. Whether the large numbers of T-cells and NK cells that are contained in the collection products may influence graft-versus-host and graft-versus-leukaemia reactivities of PBPC grafts remains to be determined.     

A prospective randomized study of clinical and economic consequences of using G-CSF following autologous peripheral blood progenitor cell (PBPC) transplantation in children

This prospective and randomized study was conducted to evaluate clinical and economic consequences of using granulocyte colony-stimulating factor (G-CSF) following autologous peripheral blood progenitor cell (PBPC) transplantation in children. Between January 1999 and December 2003, 117 patients underwent autologous PBPCT: 51 patients received G-CSF following PBPCT, while 66 patients did not receive G-CSF. Median time to absolute neutrophil count > 0.5 x 10(9)/l was 10 days in the treatment group and 11 days in the control group (P < 0.009). The median time to platelets >20 x 10(9)/l was 12 days in both groups (P = NS). The median time to platelets >50 x 10(9)/l was 15 days in the G-CSF group and 14 days in the control group (P<0.005). In patients who received <5 x 10(6)/kg CD34+ cells, the median time to platelets >20 x 10(9)/l and >50 x 10(9)/l was similar with or without G-CSF (12 and 15 days, respectively). Platelet transfusion requirements were lower in the control group (2 vs 3 U in G-CSF group). There was a trend towards higher total costs with G-CSF: 8146.82 Euros and 7873.34 Euros with and without G-CSF, respectively (P = 0.1). Our data suggest that there is no indication of the standard application of G-CSF in children following PBPC transplantation. The only possible indication is the group of patients with a lower yield of CD34+ cells.     

Telomere length predicts neutrophil recovery in the absence of G-CSF after autologous peripheral blood stem cell transplantation

Summary:Haemopoietic regeneration after autologous peripheral blood progenitor cell (PBPC) transplantation can be delayed in some patients despite adequate infusion of CD34(+) cells. This suggests variability in the proliferation potential of the implanted cells, a capacity that may be predicted by their telomere length. To test this theory, telomere length was measured on stored apheresis samples from 36 patients aged 46.6+/-11.1 years, who had undergone successful autologous PBPC transplantation with a median of 5.6 x 10(6)/kg (1.3 x 10(6)-36.1 x 10(6)/kg) CD34(+) cells. The mean PBPC telomere length for the cohort was 9.4+/-2.3 kbp. For patients who did not receive G-CSF post transplantation (n=7), days to absolute neutrophil recovery (ANC), >/=0.1, 0.5 and 1.0 x 10(9) cells/l, were significantly inversely correlated with telomere length of the infused PBPC (r=-0.88, -0.81, -0.77, respectively; P<0.05,). However, no correlation was found for patients who received G-CSF from day 1 post transplantation (n=20). These data suggest that for transplantation with sufficient CD34(+) cells, neutrophil recovery is less efficient in patients receiving infusions of cells with short telomeres, but this deficiency can be corrected with adequate post transplantation administration of G-CSF.Bone Marrow Transplantation (2004) 34, 439-445. doi:10.1038/sj.bmt.1704607 Published online 19 July 2004     

Optimizing peripheral blood progenitor cell autologous transplantation in multiple myeloma.

As in other malignancies, peripheral blood progenitor cells (PBPC) have almost completely replaced bone marrow as the source of stem cells for autologous transplantation in multiple myeloma. PBPC collection could be optimized either by reducing contamination by the malignant clone or by increasing hematopoietic quality of the graft. Currently, the most promising technique for purifying the harvest is CD34 cell selection. Several pilot studies have shown the feasibility of this method in MM. However controlled studies are necessary to assess the clinical impact of CD34+ cell selection. In the IFM 94 study, CD34+ selection was optional. There was no significant difference between 50 patients receiving a CD34+ selected graft and 133 patients receiving non-selected PBPC, as regards duration of neutropenia, duration of thrombocytopenia, response rate, EFS or survival. Hematopoietic recovery after transplantation is related to the number of CD34+ cells infused. The optimal regimen for mobilizing the requested CD34+ yield is not yet known. We have completed a randomized study comparing the combination of SCF plus G-CSF and G-CSF alone after priming with cyclophosphamide 4 g/m2. The median number of leukaphereses to reach the target yield of 5x10(6) CD34+ cells/kg was 1 in the SCF group (N=55) versus 2 in the G-CSF group (N=47) (p=0.008). The median number of CD34+ cells collected in the first leukapheresis was 11. 6x10(6) in the SCF group versus 4x10(6) in the G-CSF group (p=0.003). These results are in line with those observed in other trials testing the combination of SCF and G-CSF to improve PBPC collection.     

Patient characteristics associated with successful mobilizing and autografting of peripheral blood progenitor cells in malignant lymphoma

For patients with advanced-stage or poor-prognosis malignant lymphoma, high-dose therapy with peripheral blood progenitor cell (PBPC) support may become a first-line treatment. The duration of severe cytopenia in this setting is inversely related to the number of PBPCs autografted. In a retrospective analysis, we therefore looked for factors influencing the yield of PBPCs in 61 patients (16 with high-grade and 29 with low-/intermediate-grade non-Hodgkin's lymphoma [NHL], and 16 with Hodgkin's disease) who received cytotoxic chemotherapy and filgrastim (R-metHuG-CSF, 300 micrograms/d; median, 4.2 micrograms/kg/d; range, 2.7 to 6.6 micrograms/kg/d; subcutaneously). Sixteen patients had active disease, while 45 were in partial remission (PR) or complete remission (CR) after conventional therapy. A median of three leukaphereses (range, one to 10) resulted in a median of 5.7 x 10(6) CD34+ cells/kg (range, 0.03 to 31.1 x 10(6)). Previous cytotoxic chemotherapy and irradiation adversely affected the yield of CD34+ cells. Each cycle of chemotherapy is associated with an average decrease of 0.2 x 10(6) CD34+ cells/kg per leukapheresis in nonirradiated patients, while large-field radiotherapy reduces the collection efficiency by an average of 1.8 x 10(6)/kg CD34+ cells. The collection efficiency was also significantly lower in patients with Hodgkin's disease. However, except for one, all had been previously irradiated. In contrast, age, sex, disease status, bone marrow involvement during mobilization, and the time since the last chemotherapy or radiotherapy were not significantly related to the collection efficiency. Following high-dose conditioning therapy, 42 patients were autografted with filgrastim-mobilized PBPCs. Hematological recovery (neutrophils > or = 0.5 x 10(9)/L and an unsupported platelet count > or = 20 x 10(9)/L) within 2 weeks was observed in patients autografted with > or = 2.5 x 10(6) CD34+ cells/kg. In seven patients, the quantity of CD34+ cells reinfused was below this threshold. They required a median of 17 days (range, 11 to 34) and 31 days (range, 13 to 141) for neutrophil and platelet recovery, respectively. If autografting with PBPCs in malignant lymphoma with poor prognosis is being considered, mobilization and harvesting should be planned early after initial diagnosis to avoid exhaustion of hematopoiesis by cumulative toxicity.     

Recombinant human thrombopoietin in combination with granulocyte colony-stimulating factor enhances mobilization of peripheral blood progenitor cells, increases peripheral blood platelet concentration, and accelerates hematopoietic recovery following high-dose chemotherapy

Lineage-specific growth factors mobilize peripheral blood progenitor cells (PBPC) and accelerate hematopoietic recovery after high-dose chemotherapy. Recombinant human thrombopoietin (rhTPO) may further increase the progenitor-cell content and regenerating potential of PBPC products. We evaluated the safety and activity of rhTPO as a PBPC mobilizer in combination with granulocyte colony-stimulating factor (G-CSF) in 29 breast cancer patients treated with high-dose chemotherapy followed by PBPC reinfusion. Initially, patients received escalating single doses of rhTPO intravenously (IV) at 0.6, 1.2, or 2.4 micrograms/kg, on day 1. Subsequent patients received rhTPO 0.6 or 0.3 micrograms/kg on days -3, -1, and 1, or 0.6 micrograms/kg on days -1 and 1. G-CSF, 5 micrograms/kg IV or subcutaneously (SC) twice daily, was started on day 3 and continued through aphereses. Twenty comparable, concurrently and identically treated patients (who were eligible and would have been treated on protocol but for the lack of study opening) mobilized with G-CSF alone served as comparisons. CD34(+) cell yields were substantially higher with the first apheresis following rhTPO and G-CSF versus G-CSF alone: 4.1 x 10(6)/kg (range, 1.3 to 17.6) versus 0.8 x 10(6)/ kg (range, 0.3 to 4.2), P =.0003. The targeted minimum yield of 3 x 10(6) CD34(+) cells/kg was procured following a single apheresis procedure in 61% of the rhTPO and G-CSF-mobilized group versus 10% of G-CSF-mobilized patients (P =.001). In rhTPO and G-CSF mobilized patients, granulocyte (day 8 v 9, P =.0001) and platelet recovery (day 9 v 10, P =.07) were accelerated, and fewer erythrocyte (3 v 4, P =.02) and platelet (4 v 5, P =.02) transfusions were needed compared with G-CSF-mobilized patients. Peripheral blood platelet counts, following rhTPO and G-CSF, were increased by greater than 100% and the platelet content of PBPC products by 60% to 110% on the first and second days of aphereses (P <.0001) with the greatest effect seen with repeated dosing of rhTPO at 0.6 microgram/kg. rhTPO is safe and well tolerated as a mobilizing agent before PBPC collection. Mobilization with rhTPO and G-CSF, in comparison to a comparable, nonrandomized G-CSF-mobilized group of patients, decreases the number of apheresis procedures required, may accelerate hematopoietic recovery, and may reduce the number of transfusions required following high-dose chemotherapy for breast cancer.     

Peripheral blood CD34+ cells differ from bone marrow CD34+ cells in Thy- 1 expression and cell cycle status in nonhuman primates mobilized or not mobilized with granulocyte colony-stimulating factor and/or stem cell factor

Granulocyte colony-stimulating factor (G-CSF) and stem cell factor (SCF) have been shown to stimulate the circulation of hematopoietic progenitor cells in both mice and nonhuman primates. We evaluated the immunophenotype and cell cycle status of CD34+ cells isolated from the bone marrow (BM) and leukapheresis product of cytokine-mobilized nonhuman primates. CD34+ cells were isolated from rhesus macaques that had received no cytokine therapy, 100 micrograms/kg/d G-CSF, 200 micrograms/kg/d SCF, or a combination of both 100 micrograms/kg/d G-CSF and 200 micrograms/kg/d SCF as a subcutaneous injection for 5 days. BM was aspirated before (day 0) and on the last day (day 5) of cytokine administration. On days 4 and 5, peripheral blood (PB) mononuclear cells were collected using a novel method of leukapheresis. Threefold more PB mononuclear cells were collected from animals receiving G-CSF alone or G-CSF and SCF than from animals that had received either SCF alone or no cytokine therapy. CD34+ cells were positively selected using an immunoadsorptive system from the BM, PB, and/or leukapheresis product. Threefold and 10-fold more CD34+ cells were isolated from the leukapheresis product of animals receiving G-CSF or G-CSF and SCF, respectively, than from animals receiving no cytokine therapy or SCF alone. The isolated CD34+ cells were immunophenotyped using CD34- allophycocyanin, CD38-fluorescein isothiocyanate, and Thy-1- phycoerythrin. These cells were later stained with 4', 6-diamidino-2- phenylindole for simultaneous DNA analysis and immunophenotyping. BM- derived CD34+ cells did not differ significantly in cell cycle status and Thy-1 or CD38 phenotype before or after G-CSF and/or SCF administration. Similarly, CD34+ cells isolated from the leukapheresis product did not differ significantly in immunophenotype or cell cycle status before or after G-CSF and/or SCF administration. However, there were consistent differences in both immunophenotype and cell cycle status between BM- and PB-derived CD34+ cells. CD34+ cells isolated from the PB consistently had a smaller percentage of cells in the S+G2/M phase of the cell cycle and had a higher percentage of cells expressing Thy-1 than did CD34+ cells isolated from the BM. A greater proportion of PB-derived CD34+ cells were in the S+G2/M phase of the cell cycle after culture in media supplemented with interleukin-6 and SCF, However, culturing decreased the proportion of CD34+ cells expressing Thy-1.