Randomized Phase 2 Study Testing Two Conditioning Regimen With a Single Prophylaxis of Graft-versus-host Disease by Cyclophosphamide and Methotrexate Post-transplant in Patients Eligible for Matched-donor Allograft Transplantation

Graft-versus-host disease (GVHD) is a major complication of allogeneic hematopoietic stem cell transplantation (allo-CSH).
Recently, in the context of semi-identical (=haploidentical) HLA donors, but also of compatible HLA donors, the use of cyclophosphamide (CY) administered in high doses at early post-transplant (PT) (=PTCY) (Days +3 and +4 or +5) has shown excellent control of acute and chronic GVH, even enabling the discontinuation of other immunosuppressive drugs administered after allo-CSH (ciclosporin, mycophenolate mofetyl (MMF) or Cellcept).
This step has already been taken in the context of allo-CSH with myeloablative conditioning (MAC), which is a minoritary conditioning in adults.
However, in the context of allo-CSH with reduced-intensity conditioning (RIC), which predominates in adults, this strategy seems insufficient to prevent the risk of GVHD.
The idea of reducing the use of immunosuppressants in the context of RIC/HLA-compatible transplants seems, however, still relevant, in order to reduce their adverse effects, improve patients' quality of life and enhance the reconstitution of the post-transplant immune system.

开始日期2024-07-18

申办/合作机构

Nantes University Hospital

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1998-08-01·Leukemia Research4区 · 医学

Regulation of the expression of enzymes involved in the replication of DNA in chemically-induced granulocytic differentiation of HL-60 leukemia cells

4区 · 医学

Article

作者: John A Sokoloski ; Edward Chu ; Alan C Sartorelli ; Yixiang Chen

The expression of seven enzymes involved in the biosynthesis of DNA was measured in HL-60 promyelocytic leukemia cells treated with dimethylsulfoxide (DMSO) or all-trans retinoic acid (RA) to gain information on their role in the termination of proliferation in cells undergoing granulocytic differentiation. The steady-state levels of the mRNAs for topoisomerase I, topoisomerase II. DNA polymerase-alpha, thymidylate synthase, thymidine kinase and hypoxanthine-guanine phosphoribosyltransferase progressively declined from day 3 to day 7 of exposure to the polar solvent or the retinoid suggesting that the expression of these enzymes is coordinately regulated. In contrast, a pronounced difference between the two inducers of differentiation occurred in the expression of the mRNA of the M2 subunit of ribonucleotide reductase, with DMSO causing virtually complete inhibition of the expression of the M2 subunit of the enzyme from day 5 through day 7, with no change in the steady-state levels of the mRNA being produced by retinoic acid. Measurement of the enzymatic activities of two of these catalysts, thymidylate synthase and thymidine kinase, in cells exposed to the two inducers of maturation corroborated the findings at the level of the mRNAs, with corresponding decreases in the activity of these enzymes. The findings collectively demonstrate that the down-regulation of the expression of a relatively wide variety of enzymes involved in DNA replication occurs as late events in the granulocytic differentiation of HL-60 cells, ensuring that cellular replication cannot occur in terminally differentiated cells.

1998-08-01·Leukemia Research4区 · 医学

Regulation of the expression of enzymes involved in the replication of DNA in chemically induced monocytic/macrophagic differentiation of HL-60 leukemia cells

4区 · 医学

Article

作者: John A Sokoloski ; Edward Chu ; Alan C Sartorelli ; Yixiang Chen

The expression of a number of housekeeping enzymes of DNA biosynthesis was measured in HL-60 promyelocytic leukemia cells undergoing monocytic/macrophagic differentiation following treatment with 12-O-tetradecanoylphorbol 13-acetate (TPA) or 1alpha,25-dihydroxyvitamin D3 (vitamin D3). Progressive decreases in the steady-state levels of the mRNAs for thymidylate synthase, topoisomerase II, and hypoxanthine guanine phosphoribosyltransferase occurred following exposure to TPA or vitamin D3. In contrast, the steady-state levels of the mRNAs for thymidine kinase, topoisomerase I, and DNA polymerase-alpha did not decrease until days 3-5 of treatment with vitamin D3 and then progressively declined thereafter. The mRNAs for thymidine kinase and topoisomerase I decreased slightly and the mRNA for DNA polymerase-alpha by 30-40%, and then remained constant between days 1 to 3 of treatment with the phorbol ester. The M2 subunit of ribonucleotide reductase exhibited an even greater difference, with no change in the steady-state concentration of mRNA over 3 days of exposure to TPA or vitamin D3. On days 5-7 of treatment with vitamin D3, essentially complete loss of the expression of the mRNA for the M2 subunit of ribonucleotide reductase occurred. Measurement of the enzymatic activities of thymidylate synthase and thymidine kinase in cells exposed to either of the inducers of maturation corroborated the findings at the level of the mRNAs, with corresponding decreases in the activity of these enzymes. The results indicate that the down-regulation of the expression of housekeeping enzymes of DNA replication occurs as late events in HL-60 cells undergoing monocytic/macrophagic differentiation, implying that the decreases in their gene expression are the result of the termination of proliferation rather than an initiating event in the cessation of DNA biosynthesis.

1996-01-01·Blood

Chlorodeoxyadenosine and arabinosylcytosine in patients with acute myelogenous leukemia: pharmacokinetic, pharmacodynamic, and molecular interactions

Article

作者: Keating, MJ ; Estey, E ; Gandhi, V ; Plunkett, W ; Chucrallah, A

The effectiveness of arabinosylcytosine (ara-C) for the treatment of acute myelogenous leukemia (AML) depends on the formation of its active metabolite, the triphosphate of ara-C (ara-CTP). Using biochemical modulation strategies to increase the accumulation of ara-CTP in leukemia blasts, a clinical protocol was designed combining 2- chlorodeoxyadenosine (CdA), an inhibitor of ribonucleotide reductase, and ara-C for adults with AML. The protocol stipulated an infusion of 1 g/m2 of ara-C over 2 hours on day 1. A continuous infusion of CdA (12 mg/m2/d) begun 24 hours later and continued for 5 days. Identical doses of ara-C were administered on days 3, 4, 5, and 6. Pharmacokinetic and pharmacodynamic interactions between CdA and ara-C during therapy were investigated. To complement these studies, molecular actions of the triphosphate of ara-C and CdA on DNA extension by human DNA polymerase alpha in an in vitro model system was conducted. In the circulating leukemia blasts of 7 of the 9 patients studied, ara-CTP pharmacokinetics showed a median 40% increase in the rate of ara-CTP accumulation after 24 hours of CdA infusion. The ex vivo effect of CdA on accumulation of ara-CTP in AML blasts was similar to that during therapy except that the enhancement was less. The DNA synthetic capacity of the circulating blasts was inhibited to a greater extent by administration of CdA and ara-C in combination than by either one alone. Additionally the lowered level of DNA synthesis was maintained until the next infusion of ara-C. Endogenous levels of deoxynucleotides increased 24 hours after ara-C infusion. Administration of CdA in general lowered the concentrations of all dNTPs. DNA pol alpha incorporated CdATP and ara-CTP with high affinity in a DNA primer extending over an oligonucleotide template of defined sequence. Human DNA polymerase alpha extended DNA primers terminated by CdA monophosphate (CdAMP) at its 3′-end by incorporating ara-C monophosphate (ara-CMP). The tandem incorporation of CdAMP and ara-CMP resulted in nearly complete inhibition of DNA primer extension. The insertion of two analogs in sequence, inhibition of ribonucleotide reductase, and the metabolic potentiation of ara-CTP by CdA infusion may be responsible for sustained inhibition of DNA synthesis in the circulating leukemia blasts during therapy with this combination regimen.