Effect of etoposide (VP16-213) on lipid peroxidation and antioxidant status in a high-dose radiochemotherapy regimen

Summary A total of 13 patients receiving bone marrow transplants (BMT) for treatment of different haematological diseases were investigated. Conditioning therapy preceding BMT consisted of fractionated total-body irradiation (12 Gy) and high-dose chemotherapy with cyclophosphamide (2±60 mg/kg). Patients stratified to be at high risk for relapse (6/13) were additionally treated with etoposide (30 mg/kg). Plasma concentrations of absolute and lipid-standardized antioxidants (-tocopherol and -carotene) decreased following conditioning therapy, presumably as the result of an enhanced breakdown of these antioxidants. Etoposide treatment did not amplify the loss of essential anti-oxidants but significantly increased lipid hydroperoxide concentrations in serum. We suggest that the abnormal generation of lipid hydroperoxides is the result of free radical formation.     

Approaches to managing volunteer marrow donor registry HLA data. Algorithms for directing donor center-initiated HLA-DR typing of selected donors

The German bone marrow donor center (DKMS) hasrecruited over 732 500 donors during the first 9 years of its existence. Initially, donors were typed for HLA-A and B, and DR typing was only done on request for a patient-initiated search. In 1994, a project was started which led to the donor center-initiated DR typing (DCI-DRT) of >35,000 donors. These donors were selected by donor-specific criteria (age, sex, height and weight) and according to HLA-A and B phenotypes. The latter was done to avoid unnecessary DR typing of the most common A, B phenotypes With a follow up of >6 years, this strategy has led to a number of confirmatory typings (CT) (n=4588) and stem cell harvests (n=568), which is at least comparable to those ensuing after patient-initiated HLA-DR typing (126 000 DR typings, 8,213 CTs, 888 resulting in stem-cell donation). DCI-DRT seems to be a cost-effective strategy which may help to reduce search times and improve search outcome, and improve the overall efficiency of donor center operations     

Unaltered pharmacokinetics after the administration of high-dose etoposide without prior dilution

Summary The pharmacokinetics of etoposide following a new method of administration was determined. Undiluted etoposide was given at a dose of 30 mg/kg as part an intensified conditioning regimen prior to bone marrow transplantation. A terminal half-life of 3.4±0.7 h and a volume of distribution of 15.4±9.61 were found (n=8); the AUC was 764±302 g h ml^–1. As compared with those obtained in other pharmacokinetic studies using etoposide diluted in normal saline, our data reflect full systemic bioavailability and unaltered pharmacokinetics. The application of undiluted etoposide makes the therapy easier and less time-consuming and avoids a high fluid volume and a high saline load.     

P-glycoprotein-mediated drug efflux is a resistance mechanism of chronic myelogenous leukemia cells to treatment with imatinib mesylate.

Imatinib (Glivec), STI571) is an intracellular acting drug that demonstrates high activity against BCR-ABL-positive chronic myelogenous leukemia (CML) or acute lymphoblastic leukemia (ALL). However, many patients, especially with advanced disease, develop drug resistance. Here, we show by a novel high-performance liquid chromatography-based method that intracellular levels of imatinib decrease in P-glycoprotein (Pgp)-positive leukemic cells. In a model of K562 cells with gradually increasing Pgp expression, a Pgp-dependent decline of intracellular imatinib levels was observed. Decreased imatinib levels were associated with a retained phosphorylation pattern of the Bcr-Abl target Crkl and loss of effect of imatinib on cellular proliferation and apoptosis. The modulation of Pgp by cyclosporin A (CSA) readily restored imatinib cytotoxicity in these cells. Finally, we provide first data showing a biological effect of Pgp modulation in the imatinib treatment of a patient with BCR-ABL-positive ALL. MDR1 overexpression must therefore be considered as an important clinical mechanism in the diversity of resistance development to imatinib treatment.     

Outcome of allogeneic hematopoietic stem-cell transplantation in adult patients with acute lymphoblastic leukemia: no difference in related compared with unrelated transplant in first complete remission.

PURPOSE: The role of unrelated allogeneic stem-cell transplantation in acute lymphoblastic leukemia (ALL) patients is still not clear, and only limited data are available from the literature. We analyzed factors affecting clinical outcome of ALL patients receiving a related or unrelated stem-cell graft from matched donors. PATIENTS AND METHODS: The total study population was 264 adult patients receiving a myeloablative allogeneic stem-cell transplant for ALL at nine bone marrow transplantation centers between 1990 and 2002. Of these, 221 patients receiving a matched related or unrelated graft were analyzed. One hundred forty-eight patients received transplantation in complete remission; 62 patients were in relapse; and 11 patients were refractory to chemotherapy before transplant. Fifty percent of patients received bone marrow, and 50% received peripheral blood stem cell from a human leukocyte antigen-identical related (n = 103), or matched unrelated (n = 118) donor. RESULTS: Disease-free survival (DFS) at 5 years was 28%, with 76 patients (34%) still alive (2.2 to 103 months post-transplantation), and 145 deceased (65 relapses, transplant-related mortality, 45%). We observed an advantage regarding DFS in favor of patients receiving transplantation during their first complete remission (CR) in comparison with patients receiving transplantation in or after second CR (P =.014) or who relapsed (P <.001). We observed a clear trend toward improved survival in favor of B-lineage ALL patients compared with T-lineage ALL patients (P =.052), and Philadelphia chromosome-positive patients had no poorer outcome than Philadelphia chromosome-negative patients. Total-body irradiation-based conditioning improved DFS in comparison with busulfan (P =.041). CONCLUSION: Myeloablative matched related or matched unrelated allogeneic hematopoietic stem-cell transplantation in ALL patients should be performed in first CR.     

Allogeneic transplantation of G-CSF mobilized peripheral blood stem cells from unrelated donors: a retrospective analysis

BACKGROUND AND OBJECTIVES: Allogeneic peripheral blood stem cell transplantation (PBSCT) from matched siblings has lead to clinical results comparable to those of standard bone marrow transplantation (BMT). We report the outcome of 79 patients transplanted with PBSC from unrelated donors. DESIGN AND METHODS: In 61 cases PBSC were used for primary transplantation whereas 18 patients were treated for relapse or graft-failure. In 35 patients receiving primary transplants, T-cell depletion (TCD) using CD34 positive selection of PBSC with or without additional T-cell depletion had been performed to reduce the risk of graft-versus-host-disease (GvHD). RESULTS: The rate of primary graft-failure was higher (20%) in the TCD group than in that receiving unmanipulated grafts (UM) (5%, p=0.007). Patients with standard risk (n=34) receiving first transplants had a significantly better overall (60.4% vs. 24%, p=0.02) and disease-free survival (57.2% vs. 22.3%, p=0.006) compared to a high risk group of patients (n=21). There were no differences in the speed of neutrophil and platelet engraftment between TCD and UM transplants. As expected, the cumulative risk for acute GvHD grade II.-IV was significantly higher in the patients who had received UM grafts (71.8% vs. 38.1%, p=0.005). Although a trend towards a better survival rate was observed after TCD transplantation (52.2%) compared to the UM group (38.1%), this difference was not statistically significant. The probability of relapse was significantly higher in patients after UM transplants (38.8% vs. 8. 4%). This apparent paradox is explained by the higher number of high-risk patients in this group (p=0.03). Multivariable analysis of disease-free survival revealed risk category (p=0.02) and use of ATG (p=0.03) to be of significant impact. All patients (n=6) with non-malignant diseases are alive with full donor chimerism. INTERPRETATION AND CONCLUSIONS: These data show that PBSC from unrelated donors can be transplanted either unmanipulated or CD34 selected. Prospective studies comparing BMT with PBSCT from unrelated donors are needed in defined disease categories.     

CXCR4 blockade and Sphingosine‐1‐phosphate activation facilitate engraftment of haematopoietic stem and progenitor cells in a non‐myeloablative transplant model

Both immunosuppressive and cytoreductive effects of γ‐irradiation contribute to engraftment of allogeneic haematopoietic stem and progenitor cells. We hypothesized that a release of host stem and progenitor cells from the niche prior to conditioning would permit engraftment after less intensive conditioning. Administration of AMD3100 and SEW2871 on days ?4 to ?2 followed by irradiation on day ?1 in a non‐myeloablative zebrafish transplant model resulted in a reduced radiation minimum dose of 10 Gy from 15 Gy being sufficient for engraftment. Targeting the SDF‐1 (CXCL12)/CXCR4‐ and S1P/S1P₁‐axis increased the efficacy of allografting in an experimental transplant model.