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P Dreger

Publications and source records attributed to P Dreger.

At least 19 recordsLinked to original sources
PubMed2006

Indications for allogeneic stem cell transplantation in chronic lymphocytic leukemia: the EBMT transplant consensus.

The aim of this project was to identify situations where allogeneic stem cell transplantation (allo-SCT) might be considered as a preferred treatment option for patients with B-cell chronic lymphocytic leukemia (CLL). Based on a MEDLINE search and additional sources, a consented proposal was drafted, refined and approved upon final discussion by an international expert panel. Key elements of the consensus are (1) allo-SCT is a procedure with evidence-based efficacy in poor-risk CLL; (2) although definition of 'poor-risk CLL' requires further investigation, allo-SCT is a reasonable treatment option for younger patients with (i) non-response or early relapse (within 12 months) after purine analogues, (ii) relapse within 24 months after having achieved a response with purine-analogue-based combination therapy or autologous transplantation, and (iii) patients with p53 abnormalities requiring treatment; and (3) optimum transplant strategies may vary according to distinct clinical situations and should be defined in prospective trials. This is the first attempt to define standard indications for allo-SCT in CLL. Nevertheless, whenever possible, allo-SCT should be performed within disease-specific prospective clinical protocols in order to continuously refine transplant indications according to new developments in risk assessment and treatment of CLL.

Adolescent↗
PubMed2005

Reduced-intensity conditioning lowers treatment-related mortality of allogeneic stem cell transplantation for chronic lymphocytic leukemia: a population-matched analysis.

To elucidate whether reduced-intensity conditioning (RIC) decreases treatment-related mortality (TRM) after allogeneic stem cell transplantation (allo-SCT) for chronic lymphocytic leukemia (CLL), we retrospectively compared 73 RIC cases from a recent EBMT survey with 82 patients from the EBMT database who had undergone standard myeloablative conditioning (MC) for CLL during the same time period. The two populations were matched by adjusting the primary risk factor, the conditioning regimen, in a series of Cox models for age, sex, donor type, remission status at transplant and analyzed for its effect on TRM, relapse incidence, event-free (EFS) and overall survival (OS). After adjustment, a significant reduction of TRM became evident for the RIC population (hazard ratio (HR) 0.4 (95% confidence interval 0.18-0.9); P=0.03). On the other hand, RIC was associated with an increased relapse incidence (HR 2.65 (0.98-7.12); P=0.054). There was no significant difference between RIC and MC in terms of EFS (HR 0.69 (0.38-1.25); P=0.22) and OS (HR 0.65 (0.33-1.28); P=0.21). We conclude that RIC appears to favorably influence TRM after allo-SCT for CLL. This observation, as well as possible detrimental effects of RIC on relapse risk, should be confirmed by prospective studies.

Adult↗
PubMed2004

Modern diagnostics in chronic myeloproliferative diseases (CMPDs).

According to the new WHO classification a group of chronic myeloproliferative diseases (CMPDs) were defined: chronic myeloid leukemia (CML), chronic neutrophilic leukemia (CNL), chronic eosinophilic leukemia and hypereosinophilic syndrome (CEL/HES), polycythemia vera (PV), chronic idiopathic myelofibrosis (with extramedullary hematopoiesis, CIMF), essential thrombocythemia (ET), and so called CMPD/unclassifiable. As clinical features and laboratory findings differ widely between these diseases several diagnostic approaches are mandatory at diagnosis for classification and are needed also for follow up studies, especially for the measurement of minimal residual disease (MRD). We here outline the laboratory set up at diagnosis and during follow up in CMPDs with specific focus on the respective therapeutical consequences. Only by using a comprehensive diagnostic panel including cytomorphology, cytogenetics, and molecular genetic methods establishing the correct diagnosis, optimizing treatment as well as evaluating treatment response is possible in CMPDs today.

Blood Cell Count↗
PubMed2004

Reduced-intensity conditioning prior to allogeneic transplantation of hematopoietic stem cells: the need for T cells early after transplantation to induce a graft-versus-lymphoma effect.

In patients with poor-risk relapse of aggressive lymphoma, reduced-intensity conditioning followed by allogeneic PBSCT may have its limitations because of rapid regrowth of the tumor. We tried to address this problem by intermediate-intensity conditioning followed by allogeneic SCT. A total of 21 patients received fludarabine, busulfan and cyclophosphamide prior to allogeneic SCT. In the first 10 patients, GVHD prophylaxis by CD34+ selection of the grafts was employed (group I). The next 11 patients received nonmanipulated grafts and mycophenolat mofetil plus cyclosporinA (group II). In group I, no GVHD was observed. In contrast, patients in group II had a significant risk of acute GVHD (aGVHD) (six patients with grade II-IV acute GVHD). However, in group I, all surviving patients progressed within 9 months. In contrast, eight of nine surviving patients of group II remain in remission after a median observation time of 10.5 months (range 4-22 months). Survival differed significantly between the groups (P=0.004). Multivariate analysis identified intensive GVHD prophylaxis as important risk factor for survival. These results support the existence of a clinically relevant GVL effect in aggressive lymphoma. T-cell depletion (or CD34 selection) of grafts is not recommended in patients with poor-risk aggressive NHL.

Adolescent↗
PubMed2004

Comparative analysis of minimal residual disease detection using four-color flow cytometry, consensus IgH-PCR, and quantitative IgH PCR in CLL after allogeneic and autologous stem cell transplantation.

The clinically most suitable method for minimal residual disease (MRD) detection in chronic lymphocytic leukemia is still controversial. We prospectively compared MRD assessment in 158 blood samples of 74 patients with CLL after stem cell transplantation (SCT) using four-color flow cytometry (MRD flow) in parallel with consensus IgH-PCR and ASO IgH real-time PCR (ASO IgH RQ-PCR). In 25 out of 106 samples (23.6%) with a polyclonal consensus IgH-PCR pattern, MRD flow still detected CLL cells, proving higher sensitivity of flow cytometry over PCR-genescanning with consensus IgH-primers. Of 92 samples, 14 (15.2%) analyzed in parallel by MRD flow and by ASO IgH RQ-PCR were negative by our flow cytometric assay but positive by PCR, thus demonstrating superior sensitivity of RQ-PCR with ASO primers. Quantitative MRD levels measured by both methods correlated well (r=0.93). MRD detection by flow and ASO IgH RQ-PCR were equally suitable to monitor MRD kinetics after allogeneic SCT, but the PCR method detected impending relapses after autologous SCT earlier. An analysis of factors that influence sensitivity and specificity of flow cytometry for MRD detection allowed to devise further improvements of this technique.

Adult↗
PubMed2003

Enhanced antileukemic activity of allogeneic peripheral blood progenitor cell transplants following donor treatment with the combination of granulocyte colony-stimulating factor (G-CSF) and stem cell factor (SCF) in a murine transplantation model.

Allogeneic peripheral blood progenitor cells (PBPCs) have mostly been mobilized by granulocyte colony-stimulating factor (G-CSF). There is neither clinical nor experimental data available addressing the question if other hematopoietic growth factors or combinations thereof might influence engraftment, graft-versus-host disease (GvHD), and graft-versus-leukemia (GvL) effects after allogeneic peripheral blood progenitor cell transplantation (PBPCT). We used a murine model to investigate these parameters after transplantation of PBPCs mobilized with G-CSF and SCF either alone or in combination. Treatment of splenectomized DBA and Balb/c mice with 250 microg/kg/day G-CSF for 5 days resulted in an increase of CFU-gm from 0 to 53/microl. The highest progenitor cell numbers (147/microl) were observed after treatment with 100 microg/kg/day SCF administered in conjunction with G-SCF. No differences were detected with regard to the number of T cells (CD3+), T cell subsets (CD4+, CD8+), B cells (CD19+) and NK cells (NK1.1+) in PBPC grafts mobilized by G-CSF plus SCF compared to those mobilized with G-CSF alone. The antileukemic activity of syngeneic and MHC-identical allogeneic PBPC grafts was investigated in lethally irradiated Balb/c mice bearing the B-lymphatic leukemia cell line A20. In this model, PBPCs mobilized by G-CSF plus SCF exerted a significantly higher antileukemic activity compared to grafts mobilized by G-CSF alone (94 vs 71% freedom from leukemia at day 100, P<0.05). The antileukemic effect was lowest after BMT (38% freedom from leukemia). Since significant differences in the incidence of lethal GvHD were not observed, improved GVL-activity resulted in superior overall survival. Our data demonstrate that the utilization of specific hematopoietic growth factors not only improve the yield of hematopoietic progenitor cells but can also significantly enhance the immunotherapeutic potential of allografts.

Animals↗
PubMed2003

Treatment-related mortality and graft-versus-leukemia activity after allogeneic stem cell transplantation for chronic lymphocytic leukemia using intensity-reduced conditioning.

Allogeneic stem cell transplantation (SCT) using reduced-intensity conditioning (RIC) has potential to be a promising treatment of aggressive chronic lymphocytic leukemia (CLL). Since available clinical data obtained with this novel approach are very limited, we have performed a survey on this issue. Data of 77 patients were collected from 29 European Group for Blood and Marrow Transplantation centers. Median age was 54 (30-66) years, and the median number of previous chemotherapy regimens was 3 (0-8). HLA-identical sibling donors were used in 81% of the cases. Moderate conditioning regimens (mainly low-dose total body irradiation (TBI) or fludarabine-cyclophosphamide combinations) were administered to 56% of the patients, whereas the remainder received more intense conditioning consisting of fludarabine-busulfan or high-dose melphalan combinations. In 40% of the patients, in vivo T-cell depletion (TCD) with anti-thymocyte globulin or CAMPATH-1H was part of the conditioning regimen. Cumulative treatment-related mortality (TRM) was 18% (95% CI 9; 27) after 12 months. Complete chimerism as well as best response was not achieved immediately post-transplant but took a median of 3 months to develop. The 2-year probability of relapse was 31% (95% CI 18; 44), with no event occurring later than 12 months post transplant in the absence of TCD. With one exception, relapses were not observed after onset of chronic graft-versus-host disease. Event-free and overall survival at 24 months were 56% (95% CI 43; 69) and 72% (95% CI 61; 83), respectively. The median follow-up was 18 (1-44) months. Donor lymphocyte infusions or secondary transplants were performed in 19 patients with insufficient disease control and/or incomplete donor chimerism post-transplant, leading to a response in seven patients (37%). Preliminary multivariate analysis identified less than PR at transplant (hazard ratio (HR) 3.5; P&<0.01) and alternative donor (HR 3.1; P=0.02) as significant risk factors for relapse, whereas number of previous regimens >2 (HR 5.4; P=0.03), TBI (HR 2.5; P=0.05), and alternative donor (HR 2.3; P=0.08) were risk factors for survival. We conclude that RIC might favorably influence the outcome after allogeneic SCT for CLL by reducing TRM while preserving graft-versus leukemia activity.

Adult↗
PubMed2002

Elevated blood drug levels obtained from indwelling silicon catheters during oral cyclosporine A administration.

Cyclosporine A (CsA) may be bound to and released from the inner surface of central venous catheters resulting in spuriously elevated blood drug levels. We observed this phenomenon in a boy transplanted because of aplastic anemia up to 9 weeks after CsA had been switched from intravenous to oral administration. In comparison to phlebotomy, simultaneous blood sampling from the double lumen catheter resulted in a greater than 10-fold, or two-fold increase in drug levels, respectively, depending on whether or not the line used for prior CsA infusion was selected. Thus, prolonged binding of CsA to the inner surface of venous catheters should also be considered during oral administration.

Administration, Oral↗
PubMed2002

Autologous and allogeneic stem cell transplantation for chronic lymphocytic leukemia.

Allogeneic and autologous stem cell transplantation (SCT) are increasingly considered for treatment of patients with chronic lymphocytic leukemia (CLL). In order to assess the potential therapeutic value of SCT for CLL, the present article aims at answering the following crucial questions: (1) Is SCT a curative treatment? (2) Does SCT improve the prognosis of poor-risk CLL? (3) Do risk factors exist which are useful for defining prognostic groups in terms of feasibility and post-transplant outcome? The efficacy of auto-SCT relies exclusively on the cytotoxic therapy administered. To date, there is only limited hope that autotransplantation can cure the disease. Nevertheless, the results of the published series suggest that auto-SCT is capable of improving the prognosis of CLL with poor-risk features. Well defined favorable conditions for successful autografting are the status of the disease (CR or VGPR) and the number of lines of therapy (<2) before transplantation. The crucial anti-leukemic principle of allo-SCT consists in the immune-mediated GVL effects conferred with the graft. The GVL activity explains that allografting seems to be curative for at least a subset of patients. However, as long as allo-SCT in CLL is still associated with an excessively high treatment-related mortality, only selected patients with advanced poor-risk disease should be considered for allografting. The development of conditioning regimens with reduced intensity may allow extending the indications of allogeneic SCT for CLL in the near future.

Bone Marrow Purging↗
PubMed2002

Survival and freedom from progression in autotransplant lymphoma patients is independent of stem cell source: further follow-up from the original randomised study to assess engraftment.

Peripheral blood progenitor cells (PBPCs) have become the stem cell source of choice in autologous transplantation. In a prospective randomised trial, we previously demonstrated that autologous transplantation using filgrastim-mobilised PBPCs resulted in faster haematopoietic recovery with shorter hospitalisation and reduced platelet transfusions compared to bone marrow transplant (BMT). This study is a follow-up analysis evaluating the long-term clinical outcome. Seventy-two patients with advanced Hodgkin's disease or high-grade lymphoma were randomised to receive either filgrastim-mobilised PBPCs (n = 37) or bone marrow (n = 35) after BEAM chemotherapy. Fourteen patients withdrew from the study before commencing high-dose chemotherapy. Fourteen of the 58 patients who received treatment with chemotherapy and transplant have died, 6 (19%) in the ABMT arm and 8 (30%) in the PBPC transplant (PBPCT) arm. Twenty-five patients (81%) in the ABMT arm and 17 (63%) in the PBPCT arm, who received treatment, were in complete remission at the date of last follow-up. Progression-free survival and overall survival (OS) were similar for both arms (OS 81% at 46 months for ABMT versus 63% for PBPC; p = 0.38). Further prospective studies with larger number of patients need to be done to assess which source of stem cells may translate into a long-term clinical benefit for the patient.

Adolescent↗
PubMed2001

Allogeneic transplantation of blood stem cells: coming of age?

Mobilized peripheral blood progenitor cells (PBSC) are increasingly being used instead of bone marrow for allogeneic transplantation. The purpose of the present article is to give a concise and clinically oriented overview on current results and perspectives of allogeneic peripheral blood stem cell transplantation, with particular focus on reconstitution of hematopoiesis and the immune system, graft-versus-host disease, graft-versus-leukemia effects, intensity-reduced conditioning, and graft engineering.

Graft vs Host Disease↗
PubMed2001

Autologous stem cell transplantation for follicular lymphoma: no benefit for early transplant?

Autologous stem cell transplantation (SCT) is widely used as salvage treatment for patients with relapsed follicular lymphoma (FL). Although SCT can induce prolonged remissions, it does not appear to be curative in the vast majority of patients. The purpose of this study was to investigate if incorporation of SCT into first-line therapy can improve its efficacy. Fifty-five patients underwent sequential high-dose therapy as up-front (n=33) or salvage treatment (n=22) for advanced stage FL at our institution. Treatment consisted of intensive chemotherapy with dexamethasone, carmustine (BCNU), etoposide, cytarabine, and melphalan (Dexa-BEAM) for mobilization of peripheral stem cells and reduction of tumor load, followed by one of three different myeloablative regimens and SCT. With a median follow-up of 4 years, projected event-free survival (EFS) and overall survival (OS) at 4 years post transplant was 59% and 84%, respectively, with no evidence of plateau in the survival curves. By univariate and multivariate analysis weighing age, sex, stage, BM and extranodal involvement, timing of transplant, ex vivo purging, and conditioning regimen [total body irradiation (TBI) vs non-TBI], the only significant factor predicting for superior EFS and OS was up-front vs salvage transplant (4-year EFS 76% vs 38%, p=0.02; 4-year OS 92% vs 73%, p=0.033). However, when calculated from diagnosis, EFS and OS of the up-front and salvage groups were virtually identical, implying that the longer survival post SCT in the up-front group was completely compensated by the longer interval between diagnosis and transplant in the salvage group. Median OS from diagnosis was 13.5 years. Except for one case of anaplastic large cell lymphoma, secondary neoplasms have not occurred to date. In conclusion, our data indicate that SCT might improve the prognosis of patients with disseminated FL, although it is probably not curative even if applied early during the course of the disease. The optimum timing of SCT remains to be determined by the ongoing randomized multicenter trial of the German Low-grade Lymphoma Study Group. The impact of radiotherapy on the success of SCT does not seem to be as essential as originally believed.

Adult↗
PubMed2001

Selection of B-cell chronic lymphocytic leukemia cell variants by therapy with anti-CD20 monoclonal antibody rituximab.

OBJECTIVE: Anti-CD20 chimeric monoclonal antibody rituximab (Mabthera; IDEC-C2B8) is currently tested in several clinical trials for the treatment of B-cell chronic lymphocytic leukemia (B-CLL). In the present study, we investigated whether rituximab therapy may select for CD20(-) subclones. MATERIALS AND METHODS: Leukemic B-CLL cells were isolated from patients with B-CLL and sensitivity to rituximab-induced cell death was examined. Levels of CD20 protein and mRNA were determined using flow cytometry and real-time PCR, respectively. Clonality analyses of leukemic cells throughout rituximab therapy were performed by GeneScan analysis of patient clone specific rearrangements of the complementarity determining region III of the heavy chain immunoglobulin. RESULTS: Cytotoxicity of rituximab in vitro did not depend on the protein levels of CD20. During therapy with rituximab CD20(+) B-CLL cells were depleted and CD20(-) leukemic cells emerged. After treatment, the initial CD20(+) B-CLL cell clone reexpanded. CD20(-) B-CLL cells retained their capacity to synthesize the CD20 molecule. CONCLUSIONS: These data support the concept that in B-CLL rituximab treatment may not lead to the emergence of CD20(-) leukemic variants. Our findings support clinical studies investigating the benefit of prolonged period of rituximab therapy in B-CLL disease.

Antibodies, Monoclonal↗
PubMed2001

Sensitive and rapid quantification of busulfan in small plasma volumes by liquid chromatography-electrospray mass spectrometry.

BACKGROUND: High-dose busulfan is widely used in conditioning regimens before hematopoietic stem cell transplantation in both adults and children. Large interindividual variability in pharmacokinetics after oral administration has been reported; therefore, therapeutic drug monitoring of busulfan may decrease the incidence of drug-related toxicity (for example, hepatic venoocclusive disease) and may also improve therapeutic efficacy. METHODS: Busulfan concentrations were quantified using 200 microL of plasma and liquid-liquid extraction with diethyl ether after the addition of [2H8]busulfan as the internal standard. Separation and detection of busulfan and [2H8]busulfan were achieved with a LUNA C8 column (5 microm; 150 x 2 mm i.d.) at 30 degrees C, a HP 1100 liquid chromatography system, and a HP 1100 single-quadrupole mass spectrometer. Busulfan and [2H8]busulfan were detected as ammonium adducts in selected-ion monitoring mode at m/z 264.2 and 272.2, respectively. RESULTS: The calibration curve was linear at 5-2000 microg/L busulfan. Intra- and interassay imprecision (CV) and bias were both <11%. The limits of detection and quantification were 2 and 5 microg/L, respectively. Extraction recovery of busulfan was >87%. Analysis of pharmacokinetics in four patients receiving high-dose busulfan indicated that minimum busulfan concentrations before the next dose were 405-603 microg/L, with no interference observed. CONCLUSIONS: The new rapid and sensitive liquid chromatographic-mass spectrometric assay is an appropriate method for quantification of busulfan in human plasma, making therapeutic drug monitoring of busulfan faster and easier in clinical practice.

Adolescent↗