Mobilization of peripheral blood stem cells with docetaxel and cyclophosphamide (CY) in patients with metastatic breast cancer: a randomized trial of 3 vs 4 g/m2 of CY

Mobilization strategies for the collection of peripheral blood progenitor cells: Results from a pilot study of delayed addition G-CSF following chemotherapy and review of the literature

OBJECTIVE

Given the potential to limit cost, we conducted a pilot study evaluating delayed, low-dose granulocyte colony-stimulating factor (G-CSF) following chemotherapy for the procurement of peripheral blood progenitor cells (PBPCs) for autologous transplantation and reviewed the relevant literature.

PATIENTS AND METHODS

Twenty-eight patients with various malignancies received cyclophosphamide 4 gm/m(2) and paclitaxel 170 mg/m2 followed by G-CSF 300 microg/d or 480 microg/d starting day +5 until two to four daily large volume leukapheresis yielded > or =5.0 x 10(6) CD34+ cells. We searched MEDLINE, Pubmed, and EMBASE databases from 1990 to the present to identify papers on PBPC procurement using delayed G-CSF (starting day +4 or later) following chemotherapy.

RESULTS

G-CSF was administered for a median of 9 days at an average cost of 1260 USD per 70-kg patient. Collection was initiated at a median of 12 days after chemotherapy. A median 2.5 (range 2-4) apheresis were performed yielding an average daily CD34+ collection of 6.9 x 10(6)/kg (range 0.35-56.7). After one apheresis, 82% and 57% of patients collected > or =2.5 x 10(6)/kg and > or =5.0 x 10(6)/kg, respectively. Ultimately, 89% collected > or =5.0 x 10(6)/kg. Febrile neutropenia and catheter-related infection developed in five and two patients, respectively. All patients proceeded to transplantation and engrafted successfully with a median of 14.9 x 10(6)/kg (range 1.05-113) cells infused. Eleven published reports were identified involving 590 patients of whom 498 received G-CSF at a dose range of 250 microg/d to 10 microg/kg/d starting day +4 to 15 for a period of 4 to 9 days for PBPC procurement. Among these reports, 62 to 100% and 33 to 96% of patients collected > or =2 to 2.5 x 10(6) and > or =5.0 x 10(6) CD34+ cells, respectively.

CONCLUSION

The use of delayed, low-dose G-CSF plus chemotherapy for stem cell mobilization was feasible and provides further evidence supporting this potentially cost-effective strategy. A review of the literature supports our findings and emphasizes the need for larger studies to address this issue.

Peripheral blood hematopoietic stem cell mobilization and collection efficacy is not an independent prognostic factor for autologous stem cell transplantation

BACKGROUND

The successful mobilization and collection of hematopoietic stem cells are dependent on a number of clinical factors such as previous chemotherapy and disease stage. The aim of this retrospective study was to determine whether the effectiveness of mobilization and collection is an independent prognostic factor for autologous stem cell transplantation outcome.

STUDY DESIGN AND METHODS

A total of 358 patients who received transplants from January 2003 to December 2004 (201 male and 157 female patients, ages from 2.7 to 77.3 years with median of 53 years of age) underwent autologous hematopoietic stem cell collection after mobilization with granulocyte-colony-stimulating factor (G-CSF) or G-CSF plus chemotherapy priming. This retrospective study included patients with diagnoses of acute myelogenous leukemia, non-Hodgkin's lymphoma, Hodgkin's disease, multiple myeloma, and solid tumors. All patients underwent stem cell collection until a target or a minimum CD34+ cell dose was reached. Correlations were performed between stem cell mobilization and/or collection efficacy and transplantation outcomes.

RESULTS

In general, both larger reinfused CD34+ cell dose and shorter number of days for the stem cell count to reach the minimum of 2 x 10(6) per kg CD34+ cells do not foster quicker engraftment. Reinfused CD34+ cell dose of less than 12 x 10(6) and number of days stem cell collection to reach this minimum CD34+ cell dose did not independently affect the overall survival (OS) or disease-free survival (DFS).

CONCLUSION

The effectiveness of hematopoietic stem cell mobilization and collection as defined as number of days to reach a CD34+ cell dose of 2 x 10(6) per kg should not be used independently to forecast posttransplantation prognosis, engraftment, DFS, and OS.

Impact of chemotherapy regimen and hematopoietic growth factor on mobilization and collection of peripheral blood stem cells in cancer patients

Various chemotherapy regimens, combined with recombinant human granulocyte colony-stimulating factor(rhG-CSF) or recombinant granulocyte-macrophage CSF (rhGM-CSF) are used in cancer patients to mobilize and collect peripheral blood stem cells (PBSC). In this retrospective study, we evaluated and compared the efficacy of such regimens in 262 patients with different types of malignant diseases. The following chemotherapy regimens were applied: ifosfamide-etoposide-cisplatin or bleomycin (n = 96; mainly patients with testicular cancer); ifosfamide-etoposide plus or minus cytosine arabinoside (Ara-C) or vincristine (VCR)(n = 52; mainly patients with lymphoma); cyclophosphamide-anthracycline (n = 53; mainly patients with breast cancer); intermediate to high dose (ID-HD) cyclophosphamide (n = 37; mainly patients with breast or ovarian cancer. or multiple myeloma; and others (n = 24). rhG-CSF or rhGM-CSF, each at an average daily dose of 5 microg/kg body weight, were used in 166 and 96 patients, respectively. The study evaluated and compared the efficacy of these two cytokines. In patients receiving rhG-CSF, CD34+ cells could be collected earlier (median: day 14 versus day 16) and there was a significantly higher white blood cell count (WBC)(median 11,350 versus 5550/microl) and CD34+ cell count (median 88 versus 43/microl) at the start of apheresis, and a significantly higher CD34+ cell yield (median 7.4 x 10(6) versus 4.6 x 10(6)/kg) than in patients who receivedrhGM-CSF. Among the various chemotherapeutic regimens used, each combined with rhG-CSF, ifosfamide-etoposide plus or minus Ara-C or VCR mobilized a significantly higher number of CD34+ cells (median 119/microl) and produced a significantly higher harvest of these cells (median 13 x 10(6)/kg) than cyclophosphamide-anthracycline (median 87/microl and 7 x 10(6)/kg, respectively) or ID-HD cyclophosphamide (median 59/microl and 5 x I 0(6)/kg, respectively). Ifosfamide-etoposide plus or minus Ara-C or VCR was also superior to ifosfamide-etoposide-cisplatin or bleomycin (median 78/microl and 9 x 10(6)/kg, respectively), but at borderline significance. The outcome of PBSC mobilization and collection appeared to be negatively influenced by the number of relapses before the current salvage treatment. These data indicate that mobilization and collection of PBSCstrongly depend on the type of hematopoietic growth factor and chemotherapeutic regimen used. The data further show rhG-CSF is a more effective growth factor than rhGM-CSF and ifosfamide-etoposide-based regimens, particularly ifosfamide-etoposide plus or minus Ara-C or VCR, are highly effective regimens in mobilizing and collecting CD34+ cells.

Infectious complications in patients receiving mobilization chemotherapy for autologous peripheral blood stem cell collection

The purpose of this retrospective study was to evaluate infectious complications in patients receiving mobilization chemotherapy for stem cell collection prior to autologous peripheral blood stem cell transplantation. An additional goal was to evaluate risk factors associated with the development of infectious complications. At the Medical College of Georgia BMT center, 54 patients were administered mobilization chemotherapy for the purpose of collecting stem cells between June, 1997, and May, 2002. All patients received Filgrastim in addition to chemotherapy, and 50 of 54 patients received prophylactic acyclovir, fluconazole, and ciprofloxacin until neutrophil recovery. The median duration to neutrophil recovery was 11 days. Fourteen of 54 (26%) patients developed fever/infections during the mobilization phase. One patient developed both a catheter-related infection and Clostridium difficile colitis, increasing the total number of infectious episodes to 15. Twelve patients had a documented site of infection whereas 2 patients had neutropenic fever with no identifiable source. Eight of the 15 (55%) infections were Gram-positive catheter infections. All the patients were treated successfully with antibiotics. No systemic fungal infections were identified and none of the patients died from complications related to mobilization chemotherapy. Logistic regression was applied for univariate and multivariate analysis and showed that age, sex, diagnosis, neutrophil recovery, disease status, use of salvage chemotherapy, and mobilization regimen used did not affect the infection rate. In our series of 54 patients, 14 patients developed fever/infections during mobilization. Although there is a substantial risk of infectious complications among patients who receive mobilization chemotherapy, it is not clear that prophylactic antibiotics decrease infectious complications. Because the vast majority of infections are Gram-positive catheter infections, it appears reasonable to employ Gram-positive prophylaxis. Controlled studies should be conducted to define the optimum mobilization regimens as well as the optimum combination of prophylactic antibiotics.

Phenotypic and immunologic characteristics of docetaxel-mobilized peripheral blood stem cells in mice

Effective mobilization of peripheral blood stem cells is vital for transplantation of patients after high-dose chemotherapy and provides a convenient source of stem cells for genetic engineering and other studies, but optimal mobilization strategies have not been defined. Recent studies show that in the presence of recombinant human granulocyte colony-stimulating factor (rhG-CSF), docetaxel (DXT) is an effective mobilization agent. This study was performed to evaluate the phenotype and immunologic properties of DXT-mobilized stem cells. Administration of DXT + rhG-CSF to normal C57Bl/6 mice induced a 75-fold increase in blood hematopoietic progenitors and a significant increase in both CD3(+) (T cell) and DX5(+) [natural killer (NK)] cells when compared to untreated mice. The cytotoxicity of DXT + rhG-CSF-mobilized cell populations against YAC-1 and B16F10 cell lines was not significantly different from that of untreated mice. When compared to cyclophosphamide + rhG-CSF, DXT + rhG-CSF-mobilized cell populations yielded a greater number of T and NK cells, with significantly higher cytotoxic effector function. These results suggest that DXT + rhG-CSF-mobilized PBSCs retain potent immunologic capacity with a high number of the functional cellular subsets than those normally present in peripheral blood, which may be important in maintaining the antitumor immunity after transplantation.

Topotecan-filgrastim combination is an effective regimen for mobilizing peripheral blood stem cells

We compared the efficacy, toxicity, and cost of topotecan-filgrastim and filgrastim alone for mobilizing peripheral blood stem cells (PBSCs) in 24 consecutive pediatric patients with newly diagnosed medulloblastoma. PBSCs were mobilized with an upfront window of topotecan-filgrastim for 11 high-risk patients (residual tumor > or =1.5 cm2 after resection; metastases limited to neuraxis) and with filgrastim alone for 13 average-risk patients. All patients subsequently underwent craniospinal irradiation and four courses of high-dose chemotherapy with stem cell rescue. Target yields of CD34+ cells (> or =8 x 10(6)/kg) were obtained with only one apheresis procedure for each of the 11 patients treated with topotecan-filgrastim, but with a mean of 2.3 apheresis procedures for only six (46%) of the 13 patients treated with filgrastim alone (P = 0.0059). The median peak and median total yield of CD34+ cells were six-fold higher for the topotecan-filgrastim group (328/microl and 21.5 x 10(6)/kg, respectively) than for the filgrastim group (54/microl and 3.7 x 10(6)/kg, respectively). Mean times to neutrophil and platelet engraftment were similar. Myelosuppression was the only grade 4 toxicity associated with topotecan-filgrastim mobilization and lasted a median of 5 days. Compared with filgrastim mobilization, topotecan-filgrastim mobilization resulted in a mean cost saving of $3966 per patient. Topotecan-filgrastim is an efficacious, minimally toxic, and cost-saving combination for PBSC mobilization.

Mobilization of peripheral blood stem cells in high-risk breast cancer patients using G-CSF after standard dose docetaxel

Chemotherapy, in addition to recombinant growth factors, has been effective in mobilizing stem cells. Unfortunately, the use of chemotherapy for this purpose has resulted in profound myelosuppression and increased morbidity. Docetaxel, the single most active agent in the treatment of advanced breast cancer, was evaluated for its potential to mobilize stem cells when given at conventional doses followed by granulocyte colony-stimulating factor (G-CSF). Sixteen high-risk breast cancer patients were mobilized with a regimen consisting of docetaxel (100 mg/m2) followed by daily G-CSF (10 microg/kg), beginning 72 h after the docetaxel, and continuing until completion of the apheresis. The median white blood cell count (WBC) nadir was 1,000/microl (range 500 to 4000/microl ) occurring a median of 6 days (range 4 to 9 days) after the docetaxel. No patient experienced a neutropenic febrile episode due to the mobilization regimen. The median time interval for initiating the apheresis was 8 days (range 6 to 11 days) following the docetaxel. The median number of apheresis was 2 (range 1 to 3) in each patient. Stem cell recovery as measured by the CD34 cell count x 10(6)/kg was a median of 5.2 (range 1.4 to 15.1). A significant correlation was found between CFU-GM, BFU-E, and CFU-GEMM/kg and CD34 cells/kg (r = 0.891, 0.945, and 0.749, respectively, p < 0.001). When our results were compared to a matched cohort receiving G-CSF alone, the docetaxel group demonstrated a superior CD34 cells/kg yield (p = <0.001). Following myeloablative chemotherapy consisting of thiotepa and cyclophosphamide with or without carboplatinum, the hematopoetic recovery determined by an absolute neutrophil count (ANC) of greater than 500/microl and an unsupported platelet count of > or =20,000/microl for 48 h, was a median of 10 days (range 9 to 14 days) and 10 days (range 8 to 30 days), respectively. The results demonstrate that conventional dose docetaxel, combined with G-CSF, is an effective mobilization regimen with minimal toxicity in high-risk breast cancer patients.

Docetaxel effectively mobilizes peripheral blood CD34+ cells

We prospectively evaluated docetaxel (100 mg/m2) with G-CSF (10 microg/kg S.C., daily) for mobilization efficiency in 26 patients with breast cancer. The minimum target yield was >4.5 x 10(6) CD34+ cells/kg (optimum = 9 x 10(6)/kg), sufficient to support the subsequent three cycles of high-dose therapy (HDT). The peak days for peripheral blood (PB) CD34+ cells were day 8 and day 9. Seven collections began on day 7, 16 on day 8 and three on day 9. The median peripheral blood progenitor cell (PBPC) CD34+ cell content ranged from 1.2 to 5.9 x 10(6)/kg per day during days 7 to 11 with a median CD34+ content of the total 72 PBPC collections of 3.4 x 10(6)/kg (0.07-15.6). Fifteen patients obtained a PBPC collection exceeding 5 x 10(6)/kg on a single day of collection. Following a median 3 days collection for each patient (range 2-4), the median total CD34+ for all individual sets of collections was 9.7 x 10(6)/kg (range 1.0-28.4). We were able to achieve the minimum CD34+ cell target yield in 22 of 26 patients with one cycle of mobilisation chemotherapy and in two of these patients a second collection yielded sufficient cells. Twenty-two patients have subsequently received repetitive HDT and PBPC transplantation with 57 cycles of HDT having been delivered. For all 57 cycles, the median time to absolute neutrophil count (ANC) >0.5 x 10(9)/l and 1.0 x 10(9)/l was 10 days (range 8-22) and 11 days (range 8-23), respectively. The median time to platelets greater than 20 x 10(9)/l, 50 x 10(9)/l and 100 x 10(9)/l was 13 days (range 11-23), 17 days (range 12-53) and 23 days (range 18-70), respectively. We conclude that docetaxel with G-CSF effectively mobilises PBPCs with apheresis needing to be commenced approximately 8 days after docetaxel administration.

Selection and use of chemotherapy with hematopoietic growth factors for mobilization of peripheral blood progenitor cells

Peripheral blood progenitor cells (PBPCs) have become the preferred means of stem cell support for high-dose chemotherapy in recent years. The biology of PBPC mobilization is complex and may be influenced by several variables. Signals from both stromal and hemopoietic cells may induce downregulation of adhesion molecules and upregulate the expression of metalloproteinases. Cytokines alone can mobilize PBPCs but a synergistic effect has been shown when they are used in conjunction with chemotherapy. Disease-specific mobilization strategies appear to have the advantage of less toxicity, greater stem cell yield, and enhanced antitumor activity. Studies have demonstrated that the number of peripheral blood CD34+ cells can be used as a predictor for the timing of apheresis and for estimating PBPC yield. Similarly the CD34+ cell dose is the strongest predictor of hematologic recovery after PBPC transplant. Age, prior radiotherapy, marrow involvement, and prior chemotherapy (especially with alkylating agents) are important factors influencing the yield of stem cells.