Overview of transplant activity in Europe

Autologous hematopoietic stem cell transplantation following high-dose chemotherapy for non-rhabdomyosarcoma soft tissue sarcomas

BACKGROUND

Soft tissue sarcomas (STS) are a highly heterogeneous group of rare malignant solid tumors. Non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) comprise all STS except rhabdomyosarcoma. In patients with advanced local or metastatic disease, autologous hematopoietic stem cell transplantation (HSCT) applied after high-dose chemotherapy (HDCT) is a planned rescue therapy for HDCT-related severe hematologic toxicity.

OBJECTIVES

To assess the effectiveness and safety of HDCT followed by autologous HSCT for all stages of soft tissue sarcomas in children and adults.

SEARCH STRATEGY

We searched the electronic databases CENTRAL (The Cochrane Library 2010, Issue 2), MEDLINE and EMBASE (February 2010). Online trial registers, congress abstracts and reference lists of reviews were searched and expert panels and authors were contacted.

SELECTION CRITERIA

Terms representing STS and autologous HSCT were required in the title, abstract or keywords. In studies with aggregated data, participants with NRSTS and autologous HSCT had to constitute at least 80% of the data. Comparative non-randomized studies were included because randomized controlled trials (RCTs) were not expected. Case series and case reports were considered for an additional descriptive analysis.

DATA COLLECTION AND ANALYSIS

Study data were recorded by two review authors independently. For studies with no comparator group, we synthesised results for studies reporting aggregate data and conducted a pooled analysis of individual participant data using the Kaplan-Meyer method. The primary outcomes were overall survival (OS) and treatment-related mortality (TRM).

MAIN RESULTS

We included 54 studies, from 467 full texts articles screened (11.5%), reporting on 177 participants that received HSCT and 69 participants that received standard care. Only one study reported comparative data. In the one comparative study, OS at two years after HSCT was estimated as statistically significantly higher (62.3%) compared with participants that received standard care (23.2%). In a single-arm study, the OS two years after HSCT was reported as 20%. In a pooled analysis of the individual data of 54 participants, OS at two years was estimated as 49% (95% CI 34% to 64%). Data on TRM, secondary neoplasia and severe toxicity grade 3 to 4 after transplantation were sparse. All 54 studies had a high risk of bias.

AUTHORS' CONCLUSIONS

Due to a lack of comparative studies, it is unclear whether participants with NRSTS have improved survival from autologous HSCT following HDCT. Owing to this current gap in knowledge, at present HDCT and autologous HSCT for NRSTS should only be used within controlled trials.

Cryopreservation of hematopoietic stem/progenitor cells for therapeutic use

To date, more than 25,000 hematopoietic transplants have been carried out across Europe for hematological disorders, the majority being for hematological malignancies. At least 70% of these are autologous transplants, the remaining 30% being allogeneic, which are sourced from related (70% of the allogeneic) or unrelated donors. Peripheral blood mobilized with granulocyte colony stimulating factor is the major source of stem cells for transplantation, being used in approx 95% of autologous transplants and in approx 65% of allogeneic transplants. Other cell sources used for transplantation are bone marrow and umbilical cord blood. One crucial advance in the treatment of these disorders has been the development of the ability to cryopreserve hematopoietic stem cells for future transplantation. For bone marrow and mobilized peripheral blood, the majority of cryopreserved harvests come from autologous collections that are stored prior to a planned infusion following further treatment of the patient or at the time of a subsequent relapse. Other autologous harvests are stored as backup or "rainy day" harvests, the former specifically being intended to rescue patients who develop graft failure following an allogeneic transplant or who may require this transplant at a later date. Allogeneic bone marrow and mobilized peripheral blood are less often cryopreserved than autologous harvests. This is in contrast to umbilical cord blood that may be banked for directed or sibling (related) hematopoietic stem cell transplants, for allogeneic unrelated donations, and for autologous donations. Allogeneic unrelated donations are of particular use for providing a source of hematopoietic stem cells for ethnic minorities, patients with rare human leukocyte antigen types, or where the patient urgently requires a transplant and cannot wait for the weeks to months required to prepare a bone marrow donor. There are currently more than 200,000 banked umbilical cord blood units registered with the Bone Marrow Donors Worldwide registry. In this chapter, we describe several protocols that we have used to cryopreserve these different sources of hematopoietic stem/progenitor cells, keeping in mind that the protocols may vary among transplant processing centers.

Vinorelbine plus intermediate dose cyclophosphamide is an effective and safe regimen for the mobilization of peripheral blood stem cells in patients with multiple myeloma

High dose cyclophosphamide (HD-Cy) is commonly used to mobilize stem cells in multiple myeloma (MM). However, timing of collection is variable and incidence of side effects is substantial. We evaluated a combination of vinorelbine (VNB) (25 mg/m(2) day 1) plus Cy (1.5 g/m(2) day 2) and G-CSF as mobilizing regimen in 37 patients with MM. Results were compared to those achieved in 41 previously diagnosed patients mobilized with Cy at 4 g/m(2). Overall, 36/37 patients receiving VNB-Cy (97%) mobilized, as opposed to 40/41 (97%) in the controls (p:0.51). Median CD34+ cells peak was 94/mul for VNB-Cy patients and 96 for controls, p=0.36; median number of CD34+ cells collected was 9.2x10(6)/kg and 8.7x10(6)/kg, respectively (p=0.85). Median number of days to the highest CD34 count was shorter for VNB-Cy patients (nine vs 11, p=0.001). No VNB-Cy patient experienced grade 3-4 neutropenia and thrombocytopenia, as opposed to 63 and 19% in the controls (p=0.001 and 0.01, respectively). Hospitalization from toxicity was never required in VNB-Cy patients as compared to 19% in control group (p=0.01). We conclude that an outpatient combination of VNB plus intermediate dose Cy plus G-CSF is a safe, predictable, and highly effective mobilization regimen for patients with newly-diagnosed MM.

Dendritic cells in allogeneic hematopoietic stem cell transplantation

In allogeneic hematopoietic stem cell transplantation (SCT), dendritic cells (DCs) as the most potent antigen-presenting cells play a central role in the development of acute and chronic graft-vs-host disease (GVHD), in graft-vs-leukemia or -malignancy reactions and in fighting infectious complications. Functional maturity and distribution of DC sub-types (DC1 and DC2) differ between the different stem cell sources used (bone marrow, granulocyte colony-stimulating factor-mobilised peripheral blood and cord blood) resulting in various rates of graft-vs-host disease and graft-vs-leukemia activity. Although DC recovery following stem cell transplantation is prompt, graft-vs-host disease and the use of immunosuppressive drugs result in qualitative and quantitative disturbances in DC homeostasis and have been observed for up to 1 year after transplantation. Complete donor DC chimerism seems to be a pre-requisite for the development of chronic GVHD and for graft-vs-leukemia activity, at least following reduced-intensity transplants, although in the early phase of acute graft-vs-host disease the presence of host antigen-presenting cells is essential. Preliminary data show promising results with DC-based immunotherapy for treatment of viral and fungal infections and of leukemic relapse following allogeneic stem cell transplantation. More information on the mechanisms and interactions between dendritic cells and regulatory T cells is needed for DC vaccination concepts for modulation of graft-vs-host disease.

Allogeneic Stem Cell Transplantation

Allogeneic stem cell transplantation (HSCT) requires the harvest of an adequate number of stem cells (SC) from a histocompatible donor and their infusion into a patient following a conditioning regimen. During the past 35 years, the role of HSCT has changed from an experimental procedure for terminally ill patients to a curative treatment. In 2003, 1170 procedures were registered in Italy (Italian Group for Blood and Marrow Transplantation). The main reported indications were as follows: leukemia, lymphoproliferative diseases, myelodysplasia, and nonmalignant diseases such as thalassemia and severe aplastic anemia. Important changes have been observed in the last 5 years: the shift from bone marrow to peripheral blood as the SC source, the increasing number of alternative donors such as unrelated, partially matched family donors and cord blood SC, and the new extra-hematological indications including solid tumors. Moreover, the development of nonmyeloablative conditioning regimens have allowed physicians to perform HSCT in patients with advanced age or important comorbidities. In contrast, the availability of the Tyrosine kinase inhibitor (STI-571) for treatment of patients affected by chronic myelogenous leukemia, which was formerly the main indication for HSCT, has produced a dramatic decrease in the number of transplantations in this setting. HSCT performed in the early phases of disease and in young patients offers more than a 50% cure rate. The transplant-related mortality still represents the greatest obstacle, ranging from 20%-30%, despite the less toxic conditioning regimens, high-resolution HLA typing, and better supportive care. GvHD and infections remain the main causes of morbidity. As regards relapses, they correlate with disease status at the time of transplantation. Promising results have been recently obtained with haploidentical and with cord blood SC transplantation also in adult patients.

Evaluation and Automation of Hematopoietic Chimerism Analysis Based on Real-Time Quantitative Polymerase Chain Reaction

Abstract Chimerism analysis is an essential tool in the follow-up of patients after allogeneic stem cell transplantation. High-resolution methods for chimerism analysis based on real-time quantitative polymerase chain reaction (RQ-PCR) with a detection limit of 0.1% marker-specific cells are especially valuable in the detection of patient-derived subpopulations for the monitoring of minimal residual disease. Using artificial chimeric mixtures of genotypically different cells, we optimized and evaluated the intrasample variation, accuracy, and detection limit of chimerism analysis based on RQ-PCR of short insertion and deletion polymorphisms. Furthermore, automated setup by robot was evaluated. The results were accurate, with acceptable intrasample variation at and above 0.1% marker-specific cells. The sensitivity was mainly limited by background values. Chimerism results based on RQ-PCR were similar to results based on PCR of short tandem repeats when samples from recipients of transplants with nonmyeloablative conditioning were analyzed. Furthermore, automated setup was feasible in a time-, labor-, and reagent-conserving manner.

Stem cell medicine: umbilical cord blood and its stem cell potential

The ultimate aim of stem cell research is to improve patient outcomes and quality of life, and/or to effect a cure for a variety of inherited or acquired diseases. Improved treatments rely on developments in stem cell therapies and the discovery of new therapeutic drugs that regulate stem cell functions. These complement each other for the repair, regeneration and replacement of damaged or defective tissues. Stem cells may be sourced or derived from blood and tissues postnatally ('adult' stem cells), from the fetus (fetal stem cells) or from the blastocyst in the developing embryo prior to implantation (embryonic stem cells), each forming a unique component of the revolution in stem cell research and therapies. This review will concentrate on recent developments in the use of haemopoietic stem cells from umbilical cord blood for the transplantation of patients with haematological disorders. It will conclude with a summary of the potential of other umbilical cord blood-derived stem cells for tissue repair or regeneration.