Multicenter phase III trial to evaluate CD34(+) selected versus unselected autologous peripheral blood progenitor cell transplantation in multiple myeloma.
(17/7058)
High-dose chemotherapy followed by autologous transplantation has been shown to improve response rates and survival in multiple myeloma and other malignancies. However, autografts frequently contain detectable tumor cells. Enrichment for stem cells using anti-CD34 antibodies has been shown to reduce autograft tumor contamination in phase I/II studies. To more definitively assess the safety and efficacy of CD34 selection, a phase III study was completed in 131 multiple myeloma patients randomized to receive an autologous transplant with either CD34-selected or unselected peripheral blood progenitor cells after myeloablative therapy. Tumor contamination in the autografts was assessed by a quantitative polymerase chain reaction detection assay using patient-specific, complementarity-determining region (CDR) Ig gene primers before and after CD34 selection. A median 3.1 log reduction in contaminating tumor cells was achieved in the CD34 selected product using the CEPRATE SC System (CellPro, Inc, Bothell, WA). Successful neutrophil engraftment was achieved in all patients by day 15 and no significant between-arm difference for time to platelet engraftment occurred in patients who received an infused dose of at least 2.0 x 10(6) CD34(+) cells/kg. In conclusion, this phase III trial demonstrates that CD34-selection of peripheral blood progenitor cells significantly reduces tumor cell contamination yet provides safe and rapid hematologic recovery for patients receiving myeloablative therapy. (+info)
Genetically corrected autologous stem cells engraft, but host immune responses limit their utility in canine alpha-L-iduronidase deficiency.
(18/7058)
Canine alpha-L-iduronidase (alpha-ID) deficiency, a model of the human storage disorder mucopolysaccharidosis type I (MPS I), is an ideal system in which to evaluate the clinical benefit of genetically corrected hematopoietic stem cells. We performed adoptive transfer of genetically corrected autologous hematopoietic cells in dogs with alpha-ID deficiency. Large volume marrow collections were performed on five alpha-ID-deficient dogs. Marrow mononuclear cells in long-term marrow cultures (LTMCs) were exposed on three occasions during 3 weeks of culture to retroviral vectors bearing the normal canine alpha-ID cDNA. Transduced LTMC cells from deficient dogs expressed enzymatically active alpha-ID at 10 to 200 times the levels seen in normal dogs. An average of 32% of LTMC-derived clonogenic hematopoietic cells were provirus positive by polymerase chain reaction and about half of these expressed alpha-ID. Approximately 10(7) autologous gene-modified LTMC cells/kg were infused into nonmyeloablated recipients. Proviral DNA was detected in up to 10% of individual marrow-derived hematopoietic colonies and in 0.01% to 1% of blood and marrow leukocytes at up to 2 to 3 years postinfusion. Despite good evidence for engraftment of provirally marked cells, neither alpha-ID enzyme nor alpha-ID transcripts were detected in any dog. We evaluated immune responses against alpha-ID and transduced cells. Humoral responses to alpha-ID and serum components of the culture media (fetal bovine and horse sera and bovine serum albumin) were identified by enzyme-linked immunosorbent assay. Cellular immune responses to autologous alpha-ID but not neo(r) transduced cells were demonstrated by lymphocyte proliferation assays. To abrogate potential immune phenomena, four affected dogs received posttransplant cyclosporine A. Whereas immune responses were dampened in these dogs, alpha-ID activity remained undetectable. In none of the dogs engrafted with genetically corrected cells was there evidence for clinical improvement. Our data suggest that, whereas the alpha-ID cDNA may be transferred and maintained in approximately 5% of hematopoietic progenitors, the potential of this approach appears limited by the levels of provirally derived enzyme that are expressed in vivo and by the host's response to cultured and transduced hematopoietic cells expressing foreign proteins. (+info)
Hematopoietic stem cell tracking in vivo: a comparison of short-term and long-term repopulating cells.
(19/7058)
We have previously demonstrated that we could separate long-term repopulating stem cells from cells that provided radioprotection (short-term repopulating cells) on the basis of size and suggested that this might be due to the quiescent nature of long-term repopulating cells. To further define the activity of these populations, we used a dye (PKH26), which incorporates into the membrane of cells and is equally distributed to daughter cells when they divide. We developed an assay, which allowed us to retrieve PKH26(+) long-term and short-term repopulating cells in the hematopoietic tissues of the recipients posttransplant. We were able to recover the labeled cells and determine their cell cycle activity, as well as their ability to reconstitute secondary lethally irradiated hosts in limiting dilution. The results of our assay suggest that long-term repopulating cells are quiescent in the bone marrow (BM) 48 hours after transplant. We were able to detect only a few labeled cells in the peripheral blood posttransplant and even though cells homed to both the spleen and BM, more long-term repopulating cells homed to the marrow and only these cells, which homed to the marrow, were capable of reconstituting lethally irradiated secondary hosts long-term. (+info)
Mutant N-ras induces myeloproliferative disorders and apoptosis in bone marrow repopulated mice.
(20/7058)
Mutations that activate the N-ras oncogene are among the most frequently detected genetic alterations in human acute myeloid leukemias (AMLs), Philadelphia chromosome-negative myeloproliferative disorders (MPDs), and myelodysplastic syndromes (MDSs). However, because N-ras has not been shown to induce these disorders in an in vivo model, the role of N-ras in the evolution of myeloid leukemia is unclear. To investigate the potential of N-ras to induce myeloid leukemia, lethally irradiated mice were reconstituted with bone marrow (BM) cells infected with a retroviral vector carrying activated N-ras. Approximately 60% of these mice developed hematopoietic disorders, including severe MPDs resembling human chronic myelogenous leukemia (CML) or AML with differentiation (French-American-British [FAB] classification M2). Other reconstituted mice succumbed to hematopoietic defects that were pathologically similar to human MDSs. The latter disorders appeared to be due to a myeloid impairment that was demonstrated by enumeration of day-12 colony-forming units-spleen (CFU-S) and by in vitro colony assays. A high level of apoptosis associated with thymic atrophy and peripheral blood (PB) lymphopenia was also evident in N-ras reconstituted mice. Our results are consistent with a model in which antiproliferative effects are a primary consequence of N-ras mutations and secondary transforming events are necessary for the development of myeloid leukemia. This is the first report of an in vivo model for N-ras induced MPD and leukemia. (+info)
Pneumonia in febrile neutropenic patients and in bone marrow and blood stem-cell transplant recipients: use of high-resolution computed tomography.
(21/7058)
PURPOSE: To obtain statistical data on the use of high-resolution computed tomography (HRCT) for early detection of pneumonia in febrile neutropenic patients with unknown focus of infection. MATERIALS AND METHODS: One hundred eighty-eight HRCT studies were performed prospectively in 112 neutropenic patients with fever of unknown origin persisting for more than 48 hours despite empiric antibiotic treatment. Fifty-four of these studies were performed in transplant recipients. All patients had normal chest roentgenograms. If pneumonia was detected by HRCT, guided bronchoalveolar lavage was recommended. Evidence of pneumonia on chest roentgenograms during follow-up and micro-organisms detected during follow-up were regarded as documentation of pneumonia. RESULTS: Of the 188 HRCT studies, 112 (60%) showed pneumonia and 76 were normal. Documentation of pneumonia was possible in 61 cases by chest roentgenography or micro-organism detection (54%) (P < 10(-6)). Sensitivity of HRCT was 87% (88% in transplant recipients), specificity was 57% (67%), and the negative predictive value was 88% (97%). A time gain of 5 days was achieved by the additional use of HRCT compared to an exclusive use of chest roentgenography. CONCLUSION: The high frequency of inflammatory pulmonary disease after a suspicious HRCT scan (> 50%) proves that pneumonia is not excluded by a normal chest roentgenogram. Given the significantly longer duration of febrile episodes in transplant recipients, HRCT findings are particularly relevant in this subgroup. Patients with normal HRCT scans, particularly transplant recipients, have a low risk of pneumonia during follow-up. All neutropenic patients with fever of unknown origin and normal chest roentgenograms should undergo HRCT. (+info)
Long-term follow-up of high-risk allogeneic peripheral-blood stem-cell transplant recipients: graft-versus-host disease and transplant-related mortality.
(22/7058)
PURPOSE: To determine the risks of graft-versus-host disease (GVHD) and transplant-related mortality after allogeneic peripheral-blood stem-cell (PBSC) transplantation. PATIENTS AND METHODS: Between December 1994 and July 1996, 50 consecutive patients with high-risk hematologic malignancies in first remission or relapse received high-dose therapy followed by transplantation of granulocyte colony-stimulating factor-mobilized, allogeneic PBSCs collected from HLA-identical siblings. GVHD prophylaxis included cyclosporine and corticosteroids. RESULTS: As of April 1, 1998, 18 patients (36%+/-13%) survived with a median follow-up period of 767 days (range, 602 to 1,127 days). The actuarial probability of grades 2-4 acute GVHD was 0.37+/-0.14 (95% confidence interval). Of 36 assessable patients, 26 (72%+/-15%) developed chronic GVHD. The actuarial probability of chronic GVHD 2 years after transplantation was 0.87+/-0.15. Of 14 progression-free survivors, 11 (79%+/-22%) have active, chronic GVHD. All 11 patients require ongoing immunosuppression, and nearly two thirds have extensive disease. Thirteen patients died as a result of transplant-related mortality (26%+/-12%), six (12%) before and seven (14%) after day +100. CONCLUSION: We observed a high risk of chronic GVHD after allogeneic PBSC transplantation, which compromised the performance status of most long-term survivors and resulted in a relatively high risk of late transplant-related mortality. Approximately 75% of transplant-related deaths were associated with GVHD; thus, reduction in transplant-related mortality after allogeneic PBSC transplantation will require more effective strategies for the prophylaxis and/or treatment of GVHD. (+info)
Autologous hematopoietic stem-cell transplantation for relapsed or refractory Hodgkin's disease in children and adolescents.
(23/7058)
PURPOSE: To determine the treatment outcome and clinical factors that are of prognostic significance for children and adolescents with relapsed or refractory Hodgkin's disease (HD) who received treatment with high-dose chemotherapy and autologous hematopoietic stem-cell transplantation (HSCT). PATIENTS AND METHODS: Fifty-three consecutive children and adolescents 21 years of age or younger with relapsed or refractory HD underwent HSCT. RESULTS: At day 100 after transplantation, 29 patients (55%) were in a complete remission or maintained a continuous complete response, six (11%) had a partial response, and 11 (21%) failed to respond or had progressive disease. The failure-free survival (FFS) at 5 years was 31%, and overall survival was 43%. Twenty-one patients died of progressive HD, and nine died secondary to transplantation-related complications, including two secondary leukemias. Prognostic factors important for FFS were normal pretransplantation lactate dehydrogenase levels (5-year FFS = 42%), compared with patients with elevated LDH levels (5-year FFS = 0%) (P < .001), and disease sensitivity at the time of HSCT with FFS in untreated relapse, sensitive disease, and resistant disease 44%, 35%, and 9%, respectively (P = .06). There was no statistically significant difference in FFS or overall survival between age subgroups that were analyzed (< 13, 13 to 18, 19 to 21) or in comparison with an adult cohort. CONCLUSION: HSCT is an effective treatment modality that can result in long-term cures and should be considered for children and adolescents with relapsed HD. (+info)
Potential use of T cell receptor genes to modify hematopoietic stem cells for the gene therapy of cancer.
(24/7058)
The purpose of this review is to illustrate some of the technical and biological hurdles that need to be addressed when developing new gene therapy based clinical trials. Gene transfer approaches can be used to "mark" cells to monitor their persistence in vivo in patients, to protect cells from toxic chemotherapeutic agents, correct a genetic defect within the target cell, or to confer a novel function on the target cell. Selection of the most suitable vector for gene transfer depends upon a number of factors such as the target cell itself and whether gene expression needs to be sustained or transient. The TCR gene transfer approach described here represents one innovative strategy being pursued as a potential therapy for metastatic melanoma. Tumor reactive T cells can be isolated from the tumor infiltrating lymphocytes (TIL) of melanoma patients. A retroviral vector has been constructed containing the T cell receptor (TCR) alpha and beta chain genes from a MART-1-specific T cell clone (TIL 5). Jurkat cells transduced with this virus specifically release cytokine in response to MART-1 peptide pulsed T2 cells, showing that the virus can mediate expression of a functional TCR. HLA-A2 transgenic mice are being used to examine whether transduced bone marrow progenitor cells will differentiate in vivo into mature CD8+ T cells expressing the MART-1-specific TCR. Expression of the human TCR alpha and beta chain genes has been detected by RT-PCR in the peripheral blood of HLA-A2 transgenic mice reconstituted with transduced mouse bone marrow. Expression of the TIL 5 TCR genes in the peripheral blood of these mice was maintained for greater than 40 weeks after bone marrow reconstitution. TIL 5 TCR gene expression was also maintained following transfer of bone marrow from mice previously reconstituted with transduced bone marrow to secondary mouse recipients, suggesting that a pluripotent progenitor or lymphocyte progenitor cell has been transduced. (+info)