Transplantation of CD34+ peripheral blood cells selected using a fully automated immunomagnetic system in patients with high-risk breast cancer: results of a prospective randomized multicenter clinical trial

Critical issues on high-dose chemotherapy with autologous hematopoietic progenitor cell transplantation in breast cancer patients

INTRODUCTION

High-dose chemotherapy (HDC) with autologous hematopoietic progenitor cell transplantation (AHPCT) for high-risk (HR) or metastatic breast cancer (MBC) is no longer an option.

AREAS COVERED

An expert panel including medical oncologists and hematologists produce an opinion paper on the use of HDC and AHPCT in BC patients and they explain why they believe that; despite inconclusive results thus far, this treatment should have an ongoing role in breast cancer management under clinical trials.

EXPERT OPINION

HDC with AHPCT has become a safe treatment modality and an advantage in disease-free survival has been observed in most of the studies with HDC, with the caveat that today, even a limited relapse-free survival and progression-free survival benefit is sufficient for the approval of new antineoplastic agents. Moreover, in HRBC, an overall survival benefit by HDC could be achieved in the HER2-ve and triple-negative populations and, in this setting, HDC with AHPCT represents a therapeutic option that can be proposed to well-informed patients. In MBC, the HDC approach should be investigated further in selected patients with HER2-ve, chemosensitive disease. This paper is not intended to give any conclusion, but rather to open a debate on the value of HDC in HR and MBC.

Mobilization, harvesting and selection of peripheral blood stem cells in patients with autoimmune diseases undergoing autologous hematopoietic stem cell transplantation

Peripheral blood stem cells (PBSC) were mobilized in 130 patients with autoimmune diseases undergoing autologous hematopoietic stem cell transplantation using cyclophosphamide 2 g/m(2) and either granulocyte colony-stimulating factor (G-CSF) 5 mcg/kg/day (for systemic lupus erythematosus (SLE) and secondary progressive multiple sclerosis, SPMS) or G-CSF 10 mcg/kg/day (for relapsing remitting multiple sclerosis (RRMS), Crohn's disease (CD), systemic sclerosis (SSc), and other immune-mediated disorders). Mobilization-related mortality was 0.8% (one of 130) secondary to infection. Circulating peripheral blood (PB) CD34(+) cells/microl differed significantly by disease. Collected CD34(+) cells/kg/apheresis and overall collection efficiency was significantly better using Spectra apheresis device compared to the Fenwall CS3000 instrument. Patients with SLE and RRMS achieved the lowest and the highest CD34(+) cell yields, respectively. Ex vivo CD34(+) cell selection employing Isolex 300iv2.5 apparatus was significantly more efficient compared to CEPRATE CS device. Circulating PB CD34(+) cells/microl correlated positively with initial CD34(+) cells/kg/apheresis and enriched product CD34(+) cells/kg. Mean WBC and platelet engraftment (ANC>0.5 x 10(9)/l and platelet count >20 x 10(9)/l) occurred on days 9 and 11, respectively. Infused CD34(+) cell/kg dose showed significant direct correlation with faster white blood cell (WBC) and platelet engraftment. When adjusted for CD34(+) cell/kg dose, patients treated with a myeloablative regimen had significantly slower WBC and platelet recovery compared to non-myeloablative regimens.

Evaluation of an automated cell processing device to reduce the dimethyl sulfoxide from hematopoietic grafts after thawing

BACKGROUND

The direct transfusion of thawed hematopoietic progenitor cells (HPCs) is associated to transfusion-related side effects that are thought to be dose-dependent on the infused dimethyl sulfoxide (DMSO). Both the effectiveness of a fully automated cell processing device to washing out DMSO and the effects of DMSO elimination over the recovered cells were evaluated.

STUDY DESIGN AND METHODS

Twenty cryopre-served peripheral blood HPC bags (HPC apheresis [HPC-A]) were thawed and processed for washing with an automated cell-processing device. Viability, colony-forming units (CFUs), and absolute count of recovered cells were evaluated by flow cytometry immediately after washing as well as at different times after washing and compared with a sample taken just after thawing (control) but maintained at 4 degrees C. DMSO content was measured by high-performance liquid chromatography and the osmolarity with an osmometer.

RESULTS

The median recovery of viable total nucleated cells, viable CD34+ cells, and CFU colonies was 89 (range, 74-115), 103 (range, 62-126), and 91 percent (range, 46%-196%), respectively, in the washing group. Recovery of viable CD3+ cells was 97 percent (range, 42%-131%) and CD14+ cells was 82 percent (54%-119%). The percentages of DMSO elimination and osmolarity reduction were 98 (range, 96-99) and 90 percent (range 86%-95%), respectively. Moreover, elimination of the cryoprotectant improved CFU count, viability, and cell recoveries along the time when compared with the control group.

CONCLUSION

Washing out DMSO in thawed HPC-A by use of this approach is safe and efficient in terms of recovery and viability of nucleated and progenitor cells. Additionally, the removal degree of DMSO is very high and therefore might ameliorate the transfusion-related side effects.

The importance of National Blood Foundation funding

The research award that I received from the National Blood Foundation (NBF) was very important to me early in my career for several reasons. The funding itself was important for performing the experiments proposed, and the data obtained have played a role in much of the research that has been performed in my laboratory since that time. Also, receiving the award was a very important vote of confidence by the grant review committee at an early time in my career as an independent research scientist. Finally, because it is essential that a junior faculty member secure independent research funding, receiving this award from the NBF also represented a critical step in my career. The work that was funded by the NBF has led my laboratory down many new avenues of research, all of which have been exciting and rewarding.

Isolation and transplantation of highly purified autologous peripheral CD34+ progenitor cells: purging efficacy, hematopoietic reconstitution following high dose chemotherapy in patients with breast cancer: results of a feasibility study in Japan

BACKGROUND

High-dose chemotherapy with autologous stem cell support may have some therapeutic impact on certain groups of the patients with advanced breast cancer(BRCA). Since stem cell contamination by tumor cells might contribute to relapse, development of a tumor cell purging technique would improve the clinical outcome. The present study was undertaken to evaluate the purging efficacy of autologous mobilized CD34+peripheral stem cells in patients with breast cancer (BRCA) in an advanced stage or relapse.

METHODS

CD34+cells were selected from autologous peripheral blood stem cells (PBSC) using a clinical scale of magnetic-activated cell sorting system (CliniMACS), followed by high-dose chemotherapy with transplantation of CD34+ selected cells. Amplification of cytokeratin 19 (CK19) and 20 (CK20) gene in leukapheresis products were measured to evaluate the performance of tumor cell elimination.

RESULTS

Seven patients were entered into this study. After leukopheresis, 1 patient was dropped form this study due to poor mobilization. Among 6 patient, a total of 8 CD34+ selection was performed. The median purity and recovery rate of the CD34+ cells post selection was 85.1% (range 62.5-98.1%) and 74.2% (range 50.2-90.2%), respectively. After isolation of CD34+cells, the elimination rate in the logarithmic transformation of CK19 was 2.77 log, and that of CK20 were 2.43 log and 2.53 log. In 4 patients, high-dose chemotherapy was performed, followed by the transplantation of the isolated CD34+cells. Rapid neutrophil recovery, as well as platelet recovery was seen with a median time to reach 0.5 x 109/l neutrophils of 9 days(range 8-9), and 20 x 109/l platelets of 12 days (range 10-13). There was no treatment related death and no serious adverse events directly associated with the selection procedure or infusion of selected cells.

CONCLUSIONS

The present study demonstrated that the CliniMACS system is a highly effective positive selection method and that a high purging efficacy could be obtained without compromising the hematopoietic reconstitution capacity of the graft in BRCA patients undergoing high-dose chemotherapy.

Long-term transgene expression and survival of transgene-expressing grafts following lentivirus transduction of bone marrow side population cells

BACKGROUND

Successful transduction of hematopoietic stem cells is essential if gene therapy is to be used clinically to induce immunologic tolerance.

METHODS

Hoechst 33342 staining was used to isolate a population of bone marrow cells enriched for stem cells, termed side population (SP) cells. Murine bone marrow SP cells were transduced with HLA-A2.1-expressing VSV-G-pseudotyped lentivirus or retrovirus vectors under identical conditions.

RESULTS

After transduction without prestimulating cytokines, which minimizes cell cycling and helps maintain stem cell pluripotency, the HLA-A2.1 gene was found in the DNA of 56% of CFU-GM colonies derived from lentivirus-transduced SP cells, but in only 4% of colonies derived from retrovirus-transduced SP cells. Lentivirus and retrovirus transduction including cytokine prestimulation produced the same degree of integration as that following lentivirus-transduction of non-prestimulated cells. Transplantation of 5,000 lentivirus-transduced SP cells into lethally irradiated mice resulted in long-term expression of the HLA-A2.1 transgene in peripheral blood progeny of bone marrow SP cells and prolonged skin graft survival across this class I MHC barrier until the time of animal sacrifice.

CONCLUSIONS

Recombinant lentivirus, but not retrovirus vectors, effectively transduced SP cells that were not prestimulated with cytokines and lentivirus-transduced SP cells successfully repopulated lethally irradiated C57BL/6 mice, animals where there is no selective advantage to repopulation with transduced cells. Transplantation of a relatively small number of transduced SP cells led to prolonged transgene mRNA expression and antigen-specific survival of grafts expressing the foreign MHC transgene.

Stem-cell transplantation for the treatment of advanced solid tumors

Over the past two decades, high-dose chemotherapy (HDC) with autologous stem-cell transplantation (ASCT) has been explored for a variety of solid tumors in adults, particularly breast cancer, ovarian cancer and non-seminomatous germ-cell tumors. The results of prospective phase II studies seemed superior in many cases to the outcome expected with standard-dose chemotherapy (SDC). The value of HDC for adult solid tumors remains, in most instances, a controversial issue, currently under the scrutiny of randomized phase III trial evaluation. ASCT pursuing an immune graft-versus-tumor effect has been evaluated in recent years for patients with advanced and refractory solid malignancies. This article reviews the results of the main phase II and III studies of HDC with ASCT, as well as the preliminary experience using allogeneic transplantation for solid tumors.

Occult tumor cell contamination in patients with stage II/III breast cancer receiving sequential high-dose chemotherapy

The purpose of this study was to evaluate the presence of micrometastatic cells in the apheresis products from patients with breast cancer, and also to determine if repeated infusion of contaminated products had any clinical impact. A total of 94 patients with high-risk breast cancer were enrolled in a prospective single center study to evaluate the use of dose-intensified chemotherapy (doxorubicine 75 mg/m(2) and cyclophosphamide 3000 or 6000 mg/m(2) for four cycles) with repeated (x 2) stem cell reinfusion. All women were monitored for the presence of metastatic cells in aphereses, collected after first course of intensive chemotherapy, and following additional mobilization with rhG-CSF. Epithelial cells were screened with monoclonal antibodies directed to cytokeratin. Eight of the 94 patients had detectable tumor cells in one or several aphereses collected after intensive chemotherapy; this was unrelated to other tumor characteristics, including size, histology, Scarff Bloom and Richardson (SBR) grading (presence or absence of hormone receptors). Hemato-poietic reconstitution was similar in the cells from these eight patients, and in the total patient population. Three of these eight patients relapsed. This study has confirmed that contamination of apheresis products remains a rare event, which does not seem to affect clinical evolution, even when reinfused into the patient.

Prognostic significance of occult tumor cells in the apheresis products of patients with advanced breast cancer receiving high-dose chemotherapy and autologous hematopoietic progenitor cell support

We prospectively evaluated the prognostic significance of occult tumor cells (OTCs) contaminating the peripheral blood progenitor cell apheresis products of patients with advanced breast cancer receiving high-dose chemotherapy. Immunocytochemistry of peripheral blood progenitor cells was performed in 242 patients with high-risk primary breast cancer (HRPBC) and in 111 patients with metastatic breast cancer (MBC). OTCs were detected in 6.6% of HRPBC patients and in 16.2% of MBC patients (P = .005). In HRPBC, OTCs correlated with worse prognostic scores and larger tumor sizes, but not with axillary nodal status, hormone receptors, or HER2. In the MBC group, OTCs correlated with bone marrow involvement and with disease status at transplantation. The number of apheresis procedures was not associated with the risk of contamination. In HRPBC patients, at a median follow-up of 7 years (range, 1.5-11 years), the presence of OTCs correlated with worse event-free survival (P = .007) and overall survival (P = .002). In the MBC group, OTCs correlated with worse event-free survival (P = .04), but not overall survival (P = .2). In multivariate analyses, the presence of OTCs had an independent adverse effect on outcome in HRPBC, but not MBC. Our observations imply a direct role of OTCs in posttransplantation relapse in HRPBC.

Preclinical evaluation of an automated closed fluid management device: Cytomate, for washing out DMSO from hematopoietic stem cell grafts after thawing

Infusion of dimethylsulfoxide (DMSO) contained in cryopreserved and thawed hematopoietic stem cell (HSC) grafts is frequently associated with mild or moderate adverse reactions, and occasionally with more severe events including neurological symptoms. The severity of these complications is related to the amount of residual DMSO. We evaluated a recently available, closed, automated and 'cgmp (current good manufacturing practice) compliant' device (CytoMate) for its ability to wash out DMSO at the expense of a limited loss of viable CD34(+) cells. A total of 16 procedures were carried out with 39 blood HSC bags intended for destruction. Mean amounts of DMSO for each cellular product (one, two or three bags) were between 12.2 and 39.6 g before thawing; after the washing procedure, residual DMSO quantities were between 0.1 and 3.7 g. When set up to reproducibly allow for a more than 96% elimination of DMSO, processing of thawed cells with the CytoMate cell processor resulted in a mean recovery of viable total cells, CD34(+) cells and lymphocyte subsets above 60%. We conclude that this simple and efficient washing technique is suitable for routine processing of HSC grafts. Clinical studies will demonstrate whether a reduction in the incidence of adverse effects associated with DMSO infusion is observed.

Prognostic significance of the detection of tumour cells in peripheral blood stem cell collections in stage II and III breast cancer patients treated with high-dose therapy

The purpose of this study was to evaluate the incidence and extent of tumour cell contamination in bone marrow specimens and stem cell collections from 34 breast cancer patients undergoing high-dose therapy as adjuvant treatment, and to determine the prognostic significance for the clinical outcome. Tumour cell contamination was evaluated by flow cytometry using a double-colour test and an anti- Pan cytokeratin (CK) antibody. Two out of 34 (6%) baseline bone marrow specimens, none of seven marrow harvests and nine out of 32 aphereses (28%) mobilised from seven out of 27 patients (26%) contained CK+ cells. Tumour contamination was more frequent in patients with 10 or more involved lymph nodes and in those who received a shorter course of adjuvant chemotherapy before mobilisation. At a median follow-up of 43 months, 24 patients are in complete remission, whereas 10 patients experienced recurrence. Out of the 10 patients who relapsed, five (50%) had CK+ peripheral blood stem cell (PBSC) collections, whereas disease recurrence was seen in only two out of 24 (8%) patients who received CK- products (P=0.02). Moreover, CK+ PBSC collections were associated with a significantly shorter event-free survival and overall survival. CK+ collection is an unfavourable prognostic factor for patients treated with high-dose therapy. Whether the negative impact on clinical outcome depends on reinfusion of tumour cells or whether it simply indicates a larger disease extension is still unclear.

Transient detection of beta-galactosidase activity in hematopoietic cells, following reinjection of retrovirally marked autologous blood progenitors in patients with breast or ovarian cancer receiving high-dose chemotherapy

OBJECTIVE

The aim of this report is to demonstrate the feasibility and safety of genetically modifying autologous human blood CD34(+) cells in vitro, with a retroviral vector that encodes a marker gene. The fate of genetically modified cells and their progeny was followed in vivo, after reinfusion in patients treated with high-dose chemotherapy for poor-prognosis breast or ovarian carcinomas.

PATIENTS AND METHODS

Six patients received genetically modified autologous peripheral blood progenitors, together with unmanipulated aphereses, following high-dose chemotherapy. CD34(+) cells were immunoselected from aphereses, and retrovirally transduced by coculture with the retroviral vector producing cell line, to express a nuclear localized version of E. coli beta-galactosidase, encoded by a defective Moloney-murine leukemia virus-derived retroviral vector. Cells were reinfused to the patients after myeloablation, without prior ex vivo selection.

RESULTS

Five out of six patients showed the transient presence of low numbers of beta-galactosidase(+) cells, as detected with an immunocytochemical assay, in the peripheral blood, during the first month following infusion. One patient had beta-galactosidase(+) clonogenic progenitors in her marrow at two months after transplantation, including HPP-CFC; intriguingly, this patient had the lowest percentage of X-gal(+) cells in her graft. Patients experienced side effects that are often observed after high-dose chemotherapy.

CONCLUSIONS

Feasibility and safety of genetic modification of human hematopoietic stem and progenitor cells are demonstrated by this study. Ex vivo or in vivo selection is not mandatory, even in clinical situations where transduced cells have no survival advantage over wild-type cells; however, significant improvements in gene transfer technology are needed to achieve potentially useful levels of expression in such clinical situations.

High-dose chemotherapy and CD34-selected peripheral blood progenitor cell transplantation for patients with breast cancer metastatic to bone and/or bone marrow

Fifty women with breast cancer metastatic to bone or bone marrow involvement on light microscopy at the time of initial evaluation were treated with high-dose chemotherapy (HDC) and peripheral blood progenitor cell (PBPC) transplantation with CD34(+) cell selection using the Isolex 300i system. All patients received induction chemotherapy. PBPC were mobilized with chemotherapy and granulocyte colony-stimulating factor. The median CD34(+) progenitor purity was 94.7% (range 72-98.7%) and recovery 38.4% (range 21-60%). Forty-eight hours after HDC with cyclophosphamide, cisplatin and carmustine, PBPC were reinfused. Median time to neutrophil count >0.5 x 10(9)/l was 9 (range 9-12) days and to platelet transfusion independence 11 (4-30) days. These data demonstrate that selected CD34(+) PBPCs allow rapid hematologic reconstitution after HDC. During follow-up, 23% of patients developed herpes zoster. Two patients developed cytomegalovirus infections. Three patients developed fungal infections. The development of these infections was not associated with steroid use but appeared more frequently in patients with diabetes mellitus. Seventy-four per cent of patients received steroids for pulmonary toxicity. Treatment-related mortality was 4%. Progression-free survival and overall survival at 35 months was 22.4% and 40.5%, with a median of 11.4 months and 15.4 months, respectively.

Ex vivo purging by adenoviral p53 gene therapy does not affect NOD-SCID repopulating activity of human CD34+ cells

Co-incubation of a replication-deficient, recombinant adenovirus carrying the wild-type p53 gene (rAd-p53) and hematopoietic stem cell (HSC) products from patients with breast cancer can significantly reduce tumor cell contamination. Whereas this approach provides a powerful tumor cell purging strategy, potential detrimental effects on the HSC population have not been investigated. The ability of human HSC to reconstitute hematopoiesis in severe combined immunodeficient (SCID) mice and to undergo secondary transplantation provides the only nonclinical measure of self-renewing, stem cell function. The objective of this study was to investigate whether co-incubation with rAd-p53 compromised the SCID repopulating activity (SRA) of HSC. Granulocyte colony-stimulating factor-mobilized human CD34+ cells were co-cultured with rAd-p53 at our targeted clinical dose, and the ability of these cells to establish multilineage hematopoiesis in sublethally irradiated, nonobese diabetic (NOD)-SCID mice was investigated. The persistence of human cells in the mice was investigated by flow cytometry, granulocyte-macrophage colony-forming unit assay, and polymerase chain reaction of human Alu sequences. Further, limiting dilution analysis provided a quantitative comparison between the SRA of CD34+ cells co-incubated with rAd-p53 and control CD34+ cells (no rAd-p53 co-incubation). We conclude that co-incubation with rAd-p53 has little effect on the SRA of HSC.

High-dose chemotherapy with hematopoietic stem-cell transplantation for breast cancer: current status, future trends

High-dose chemotherapy with hematopoietic stem-cell transplantation (HDC/HSCT) has been extensively studied as a potential treatment for breast cancer. A literature search of MEDLINE from January 1990 through December 1999 identified 497 published full papers. Of these articles, 120 reported the results of clinical trials, 78 were reviews, and 299 reported on issues related to the technology of peripheral stem cells, supportive care, and toxicity. The phase II data must be interpreted with caution, as it is subject to selection bias; transplant recipients tended to be younger, rigorously staged, and selected to be chemotherapy responsive. There continues to be controversy regarding the role of high-dose therapy in this disease. Only a few fully published randomized trials are available; these studies were powered only to detect large differences in survival and no benefit was shown. Several large controlled trials are either in progress or are too early for definitive analysis. This review analyzes the current literature on HDC/HSCT for breast cancer, identifying prognostic factors and discussing ongoing research designed to improve antitumor effects.