Sequential use of intensive chemotherapy, RIC transplantation, and pDLT represents a promising approach to the treatment of high-risk AML and MDS, particularly in patients with most unfavorable prognoses.
A sequential regimen of chemotherapy, reduced-intensity conditioning (RIC) for allogeneic stem cell transplantation (SCT), and prophylactic donor lymphocyte transfusion (pDLT) was studied in 103 patients with refractory acute myeloid leukemia (AML). According to published criteria, refractoriness was defined by primary induction failure (PIF; n ؍ 37), early (n ؍ 53), refractory (n ؍ 8), or second (n ؍ 5) relapse. Chemotherapy consisted of fludarabine (4 ؋ 30 mg/m 2 ), cytarabine (4 ؋ 2 g/m 2 ), and amsacrine (4 ؋ 100 mg/ m 2 ), followed 4 days later by RIC, comprising 4 Gy total body irradiation (TBI), cyclophosphamide, and antithymocyte globulin. Patients without graft-versus-host disease (GvHD) at day ؉120 received pDLT in escalating doses. Patients' median age was 51.8 years. Before conditioning, 99 patients had active disease, 3 were aplastic, 1 was in second complete remission (CR2). Forty-one patients had family donors, 62 had unrelated donors. With a 25-month median follow-up, overall survival (OS) at 1, 2, and 4 years was 54%, 40%, and 32%; the respective leukemiafree survival (LFS) was 47%, 37%, and 30%. Patients with PIF showed a 2-year OS of 62.5%. OS was 87% in 17 patients receiving pDLT. One-year cumulative incidence of leukemic death and non-relapsemortality was 28.7% and 17.2%. In a multivariate analysis, more than 2 courses of prior chemotherapy were the strongest predictor for poor outcome (P ؍ .007; HR ؍ 3.01 [OS]; P ؍ .002; HR ؍ 3.25 [LFS]). These results indicate a high activity of the regimen in refractory AML.
PURPOSE Despite undergoing allogeneic hematopoietic stem cell transplantation (HCT), patients with acute myeloid leukemia (AML) with internal tandem duplication mutation in the FMS-like tyrosine kinase 3 gene ( FLT3-ITD) have a poor prognosis, frequently relapse, and die as a result of AML. It is currently unknown whether a maintenance therapy using FLT3 inhibitors, such as the multitargeted tyrosine kinase inhibitor sorafenib, improves outcome after HCT. PATIENTS AND METHODS In a randomized, placebo-controlled, double-blind phase II trial (SORMAIN; German Clinical Trials Register: DRKS00000591), 83 adult patients with FLT3-ITD–positive AML in complete hematologic remission after HCT were randomly assigned to receive for 24 months either the multitargeted and FLT3-kinase inhibitor sorafenib (n = 43) or placebo (n = 40 placebo). Relapse-free survival (RFS) was the primary endpoint of this trial. Relapse was defined as relapse or death, whatever occurred first. RESULTS With a median follow-up of 41.8 months, the hazard ratio (HR) for relapse or death in the sorafenib group versus placebo group was 0.39 (95% CI, 0.18 to 0.85; log-rank P = .013). The 24-month RFS probability was 53.3% (95% CI, 0.36 to 0.68) with placebo versus 85.0% (95% CI, 0.70 to 0.93) with sorafenib (HR, 0.256; 95% CI, 0.10 to 0.65; log-rank P = .002). Exploratory data show that patients with undetectable minimal residual disease (MRD) before HCT and those with detectable MRD after HCT derive the strongest benefit from sorafenib. CONCLUSION Sorafenib maintenance therapy reduces the risk of relapse and death after HCT for FLT3-ITD–positive AML.
There is a strong graft-versus-leukemia (GVL) effect of allogeneic stem cell transplantation (SCT) due to elimination of tumor cells by alloimmune effector lymphocytes. When leukemia relapses after allogeneic SCT, donor lymphocyte transfusions (DLTs) can induce sustained remissions in some patients. This review summarizes the current status on clinical use of DLT, the basis of GVL reactions, problems associated with this therapy, and new strategies to improve DLT. Several multicenter surveys demonstrated that the GVL effect of DLT is most effective in chronic myelogenous leukemia (CML), whereas it is less pronounced in acute leukemia and myeloma. Cytokine stimulation to induce differentiation of myeloid progenitor cells or to up-regulate costimulatory molecules on tumor cells may improve the efficacy of DLT. Infections and graft-versus-host disease (GVHD) are major complications of DLT. Control of GVHD may be improved using suicide gene-modified T cells for DLT, allowing T-cell elimination if severe GVHD develops. Hopefully, in the future, GVL effect can be separated from GVHD through adoptive transfer of selected T cells that recognize leukemia-specific antigens or minor histocompatibility antigens, which are expressed predominantly on hematopoietic cells, thereby precluding attack of normal tissues. In patients with leukemia and lymphomas with fast progression, tumor growth may outpace development of effector T cells. Here it may be preferable to select stem cell transplant donors with HLA-mismatches that allow alloreactive natural killer cells, which appear early after transplantation, to retain their cytolytic function. New approaches for adoptive immune therapy of leukemia, which promise a better prognosis for these patients, are being developed. IntroductionAllogeneic stem cell transplantation (SCT) is an established form of treatment for leukemia and is now being explored as a treatment for a variety of other hematologic and nonhematologic malignancies. In the last decade, the paradigm for treatment of leukemia by SCT has changed. The initial focus was to use myeloablative doses of radiation and chemotherapy to eliminate the leukemia, and SCT was performed to prevent death from marrow failure. Increasingly today, the emphasis has shifted to eradicating leukemia with alloimmune effector cells, while limiting radiation and chemotherapy to those doses sufficient to permit donor stem cell engraftment as a platform for adoptive immune therapy and reducing the conditioning toxicity for SCT.The antileukemia effect of the graft-versus-host (GVH) reaction was recognized early in murine models 1 and soon applied to human patients. 2 A systematic analysis by the Seattle team showed that patients surviving acute graft-versus-host disease (GVHD) benefited from a reduced tumor relapse rate. 3 The important role of T cells in eliminating chronic myelogenous leukemia (CML) was suggested by a retrospective study of the International Bone Marrow Transplant Registry (IBMTR), 4 which found an increased leukemia relapse rate...
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