Current status of reduced intensity conditioning allogeneic stem cell transplantation for acute myeloid leukemia

Allogeneic stem cell transplantation (allo-SCT) is the most efficient antileukemic treatment for acute myeloblastic leukemia (AML). However, elderly patients can rarely benefit from standard myeloablative allo-SCT because of an unacceptable rate of procedure-related toxicities. This point is critical when considering AML patients in first complete remission. The development of the so-called reduced-intensity conditioning (RIC) regimens appears to decrease allo-SCT-related toxicities, and has emerged as an attractive modality in AML patients not eligible for standard allo-SCT. Such RIC regimens aim primarily to provide the immune graft-versus-leukemia effect while causing little toxicity. Of note, treatment-related toxicity appears to be lower with RIC regimens as compared to standard myeloablative regimens. Nevertheless, toxicity might represent only one aspect of the problem, since AML encompasses a group of chemosensitive diseases, raising concerns that significant reduction of the intensity of the preparative regimen may have a negative impact on long-term leukemic control. Furthermore, no prospective studies have been reported thus far establishing RIC allo-SCT as the preferred option in AML. Investigators are currently faced with a dilemma on how to optimize the potential role of RIC allo-SCT in AML patients, while delivering minimal myeloablation and maximizing allogeneic immunotherapy. The aim of this review is to analyze the available research evidence in this field

MIRROS: a randomized, placebo-controlled, Phase III trial of cytarabine ± idasanutlin in relapsed or refractory acute myeloid leukemia.

Patients with refractory or relapsed acute myeloid leukemia (R/R AML) have a poor prognosis, with a high unmet medical need. Idasanutlin is a small-molecule inhibitor of MDM2, a negative regulator of tumor suppressor p53. By preventing the p53–MDM2 interaction, idasanutlin allows for p53 activation, particularly in patients with TP53 wild-type (WT) status. MIRROS (NCT02545283) is a randomized Phase III trial evaluating idasanutlin + cytarabine versus placebo + cytarabine in R/R AML. The primary end point is overall survival in the TP53-WT population. Secondary end points include complete remission rate (cycle 1), overall remission rate (cycle 1) and event-free survival in the TP53-WT population. MIRROS has an innovative design that integrates a stringent interim analysis for futility; continuation criteria were met in mid-2017 and accrual is ongoing. Trial registration number: NCT0254528

Antithymocyte Globulin in Reduced-Intensity Conditioning Regimen Allows a High Disease-Free Survival Exempt of Long-Term Chronic Graft-versus-Host Disease

AbstractNonmyeloablative (NMA) regimens allow the use of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients considered unfit for standard myeloablative conditioning (MAC) regimens using high-dose alkylating agents with or without total body irradiation (TBI). Reduced-intensity conditioning (RIC) regimens, based on fludarabine (Flu), busulfan (Bu), and rabbit antithymocyte globulin (r-ATG), represent an intermediate alternative between NMA and MAC regimens. This platform was subsequently optimized by the introduction of i.v. Bu and the use of 5 mg/kg r-ATG, based on the hypothesis that these modifications would improve the safety of RIC allo-HSCT. Here we report a study conducted at our institution on 206 patients, median age 59 years, who underwent allo-HSCT after conditioning with Flu, 2 days of i.v. Bu, and 5 mg/kg r-ATG (FBx-ATG) between 2005 and 2012. The prevalence of grade III-IV acute graft-versus-host disease (GVHD) was 9%, and that of extensive chronic GVHD was 22%. Four-year nonrelapse mortality (NRM), relapse, and overall survival (OS) rates were 22%, 36%, and 54%, respectively. NRM tended to be influenced by comorbidities (hematopoietic cell transplantation–specific comorbidity index [HCT-CI] <3 versus HCT-CI ≥3: 18% versus 27%; P = .075), but not by age (<60 years, 20% versus ≥60 years, 25%; P = .142). Disease risk significantly influenced relapse (2 years: low, 8%, intermediate, 28%, high, 34%; very high, 63%; P = .017). Both disease risk (hazard ratio [95% confidence interval]: intermediate, 2.1 [0.8 to 5.2], P = .127; high, 3.4 [1.3 to 9.1], P = .013; very high, 4.0 [1.1 to 14], P = .029) and HCT-CI (hazard ratio [95% confidence interval]: HCT-CI ≥3, 1.7 (1.1 to 2.8), P = .018) influenced OS, but age and donor type did not. The FBx-ATG RIC regimen reported here is associated with low mortality and high long-term disease-free survival without persistent GVHD in both young and old patients. It represents a valuable platform for developing further post-transplantation strategies aimed at reducing the incidence of relapse, particularly in the setting of high-risk disease

Clinical practice recommendation on hematopoietic stem cell transplantation for acute myeloid leukemia patients with FLT3 internal tandem duplication: a position statement from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

The FMS-like tyrosine kinase 3 (FLT3) gene is mutated in 25-30% of patients with acute myeloid leukemia . Because of the poor prognosis associated with FMS-like tyrosine kinase 3 internal tandem duplication mutated Acute myeloid leukemia, allogeneic-hematopoietic stem-cell transplantation was commonly performed in first complete remission. Remarkable progress has been made in frontline treatments with the incorporation of FLT3 inhibitors and the development of highly sensitive minimal/measurable residual disease assays. Similarly, recent progress in allogeneic-hematopoietic stem-cell transplantation includes improvement of transplant techniques, the use of haplo-identical donors in patients lacking an HLA matched donor, and the introduction of FLT3 inhibitors as posttransplant maintenance therapy. Nevertheless, current transplant strategies vary between centers and differ in terms of transplant indications based on the internal tandem duplication allelic ratio and concomitant nucleophosmin-1 mutation, as well as in terms of post-transplant maintenance/consolidation. This review generated by international leukemia or transplant experts, mostly from the European Society for Blood and Marrow Transplantation, attempts to develop a position statement on best approaches for allogeneic-hematopoietic stem-cell transplantation for acute myeloid leukemia with FMS-like tyrosine kinase internal tandem duplication including indications and modalities of allogeneic-hematopoietic stem-cell transplantation and on potential optimization of post-transplant maintenance with FMS-like tyrosine kinase inhibitors

Outcome of older (≥70 years) APL patients frontline treated with or without arsenic trioxide-an International Collaborative Study

Data on outcome in older (≥70 years) patients with acute promyelocytic leukemia after treatment with arsenic trioxide (ATO) compared with standard chemotherapy (CTX) is scarce. We evaluated 433 patients (median age, 73.4 years) treated either with ATO+ all-trans retinoic acid (ATO/ATRA; n = 26), CTX/ATRA + ATO during consolidation (CTX/ATRA/ATO; n = 148), or with CTX/ATRA (n = 259). Median follow-up for overall survival (OS) was 4.8 years. Complete remissions (CR) were achieved in 92% with ATO/ATRA and 82% with CTX/ATRA; induction death rates were 8% and 18%, respectively. For analysis of postremission outcomes we combined the ATO/ATRA and CTX/ATRA/ATO groups (ATO/ATRA ± CTX). Cumulative incidence of relapse (CIR) was significantly lower after ATO/ATRA ± CTX compared with CTX/ATRA (P 10 × 10 9 /l) white blood cell (WBC) counts at diagnosis were associated with higher CIR (P < 0.001) compared with lower WBC in the CTX/ATRA group, but not in the ATO/ATRA ± CTX group (P = 0.48). ATO, when added to ATRA or CTX/ATRA is feasible and effective in elderly patients for remission induction and consolidation, particularly in patients with high WBC at diagnosis

Acute myeloid leukemia patients’ clinical response to idasanutlin (RG7388) is associated with pre-treatment MDM2 protein expression in leukemic blasts

In translational research described, we investigated biomarker expression by flow cytometry for MDM2 antagonist clinical response association in relapsed/refractory AML patients treated with idasanutlin-based therapy (Clinicaltrials.gov identifier: NCT01773408)