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Nucleophosmin-1 (NPM1) mutations in acute myeloid leukemia (AML) confer a survival advantage in the absence of FLT3-internal tandem duplication (FLT3-ITD). Here, we investigated the main predictors of outcome after allogeneic hematopoietic stem cell transplantation (allo-HCT). We identified 1572 adult (age ≥ 18 year) patients with NPM1-mutated AML in first complete remission (CR1:78%) or second complete remission (CR2:22%) who were transplanted from matched sibling donors (30.8%) or unrelated donors (57.4%) between 2007 and 2019 at EBMT participating centers. Median follow-up for survivors was 23.7 months. FLT3-ITD was present in 69.3% of patients and 39.2% had detectable minimal/measurable residual disease (MRD) at transplant. In multivariate analysis, relapse incidence (RI) and leukemia-free survival (LFS) were negatively affected by concomitant FLT3-ITD mutation (HR 1.66 p = 0.0001, and HR 1.53, p < 0.0001, respectively), MRD positivity at transplant (HR 2.18, p < 10-5 and HR 1.71, p < 10-5, respectively), and transplant in CR2 (HR 1.36, p = 0.026, and HR 1.26, p = 0.033, respectively), but positively affected by Karnofsky score ≥90 (HR 0.74, p = 0.012, and HR 0.7, p = 0.0002, respectively). Overall survival (OS) was also negatively influenced by concomitant FLT3-ITD (HR 1.6, p = 0.0001), MRD positivity at transplant (HR 1.61, p < 10-5), and older age (HR 1.22 per 10 years, p < 0.0001), but positively affected by matched sibling donor (unrelated donor: HR 1.35, p = 0.012; haploidentical donor: HR 1.45, p = 0.037) and Karnofsky score ≥90 (HR 0.73, p = 0.004). These results highlight the independent and significant role of FLT3-ITD, MRD status, and disease status on posttransplant outcomes in patients with NPM1-mutated AML allowing physicians to identify patients at risk of relapse who may benefit from posttransplant prophylactic interventions. [ABSTRACT FROM AUTHOR]

Measurable residual disease (MRD) prior to hematopoietic cell transplant (HCT) for acute myeloid leukemia (AML) in first complete morphological remission (CR1) is an independent predictor of outcome, but few studies address CR2. This analysis by the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation registry assessed HCT outcomes by declared MRD status in a cohort of 1042 adult patients with AML CR2 at HCT. Patients were transplanted 2006–2016 from human leukocyte antigen (HLA) matched siblings (n = 719) or HLA 10/10 matched unrelated donors (n = 293). Conditioning was myeloablative (n = 610) or reduced-intensity (n = 432) and 566 patients (54%) had in-vivo T cell depletion. At HCT, 749 patients (72%) were MRD negative (MRD NEG) and 293 (28%) were MRD positive (MRD POS). Time from diagnosis to HCT was longer in MRD NEG than MRD POS patients (18 vs. 16 months (P < 0.001). Two-year relapse rates were 24% (95% CI, 21–28) and 40% (95% CI, 34–46) in MRD NEG and MRD POS groups (P < 0.001), respectively. Leukemia-free survival (LFS) was 57% (53–61) and 46% (40–52%), respectively (P = 0.001), but there was no difference in terms of overall survival. Prognostic factors for relapse and LFS were MRD NEG status, good risk cytogenetics, and longer time from diagnosis to HCT. In-vivo T cell depletion predicted relapse. [ABSTRACT FROM AUTHOR]

The Acute Leukemia Working Party (ALWP) of the EBMT assessed the outcome of allogeneic stem cell transplantation (alloSCT) in patients with relapsed/refractory AML (r/rAML) evaluating six sequential conditioning regimens (SR) groups. A total of 2132 patients were included. LFS at 2 years was 28.9%, 33.6%, 35.3%, 20.6%, 24.4%, and 27% for the FLAMSA-TBI4, FLAMSA-Chemo, Mel-Flu-TBI8, Mel-Treo-Flu, Thio-ETO-Cy-Bu2-Flu, and Clo-ARAC-(Bu2/TBI4)-Cy groups, respectively. In patients <55 years of age Mel-Flu-TBI8 had the best LFS, which was statistically significant only in comparison to the Mel-Treo-Flu group, while in patients ≥55 years LFS was best with FLAMSA-Chemo without significant differences compared to FLAMSA-TBI4 and Mel-Flu-TBI8. Furthermore, best NRM rates were obtained with the two FLAMSA regimens groups. Our study suggests that in younger (<55 years) patients a more intense regimen might be used whereas in older (≥55 years) patients the focus might be more on tolerability. [ABSTRACT FROM AUTHOR]

Following chemotherapy, secondary acute myeloid leukemia (sAML), occurring after antecedent hematologic diseases, previous chemotherapy or radiation, has an inferior prognosis compared with de novo AML. To define the outcome of sAML in the context of allogeneic stem cell transplantation (alloSCT), a retrospective, registry-based comparison was performed, including 11,439 patients with de novo and 1325 with sAML. Among transplants in first complete remission (CR1) (n = 8,600), the 3-year cumulative incidence of relapse (RI) and non-relapse mortality (NRM) was 28.5% and 16.4% for de novo, and 35% and 23.4% for sAML. Three-year overall survival (OS), leukemia-free survival (LFS) and Graft-versus-Host Disease/relapse-free survival (GRFS) was 60.8%, 55.1%, and 38.6% for de novo, and 46.7%, 41.6%, and 28.4% for sAML, respectively. In multivariate analysis, sAML was associated with a lower OS (HR = 1.33 [95% CI = 1.21–1.48]; p < 10−5), LFS (HR = 1.32 [95% CI = 1.19–1.45]; p < 10−5) and GRFS (HR = 1.2 [95% CI = 1.1–1.31]; p < 10−4) and higher NRM (HR = 1.37 [95% CI = 1.17–1.59]; p < 10−4) and RI (HR = 1.27 [95% CI = 1.12–1.44]; p < 10−3). Results of the Cox model were confirmed in a matched-pair analysis. In contrast, results did not differ between de novo and sAML after alloSCT in induction failure or relapse. Hence, this analysis identified sAML as an independent risk factor for outcome after alloSCT in CR1. [ABSTRACT FROM AUTHOR]

Highlights • Major mechanisms of relapse include HLA loss, HLA down-regulation, and expression of coinhibitory ligands. • Combination of donor lymphocyte infusion with immunomodulating agents and tyrosine kinase inhibitors may enhance the graft-versus-leukemia (GVL) effect. • Immune checkpoint inhibitors can induce a significant GVL effect, but toxicity is high. ABSTRACT The curative potential of allogeneic hematopoietic cell transplantation (allo-HCT) in the treatment of acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS) relies mainly on the graft-versus-leukemia effect. Relapse after allo-HCT occurs in a considerable proportion of patients and has a dismal prognosis, with still very limited curative potential. This review provides an overview of the established and evolving approaches to preventing or treating relapse of AML and MDS after allo-HCT, in the context of novel insight into the biology of relapse. Established prophylactic measures to prevent relapse include optimized conditioning and graft-versus-host disease (GVHD) prophylaxis, as well as donor lymphocyte infusion (DLI) for high-risk patients; novel immunomodulatory interventions and maintenance approaches are still experimental. Improved diagnostics can detect persistent or recurring disease at a molecular level, enabling early preemptive interventions. Established options include hypomethylating agents and DLI. Standard treatments for hematologic relapse include chemotherapy, cessation of immunosuppressive treatment, and DLI. Experimental approaches include molecular targeted therapies, novel immunomodulatory treatments, and second allo-HCT. For all interventions, the potential risks, including occurrence of GVHD, must be weighed against the benefits individually in each patient. Concurrently, prevention and treatment of relapse after allo-HCT remain challenging and unmet medical needs. [ABSTRACT FROM AUTHOR]

Highlights • The impact of donor age and sex but not CMV matching is comparable with that of single HLA disparity on survival after HSCT. • Similar survival after matched unrelated and related donor HSCT for AML or MDS reflects lower NRM but higher relapse risks in the latter. Abstract Increasing donor–recipient HLA disparity is associated with negative outcomes of allogeneic hematopoietic stem cell transplantation (HSCT), but its comparative relevance amid non-HLA donor characteristics is not well established. We addressed this question in 3215 HSCTs performed between 2005 and 2013 in Germany for acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS). Donors were HLA-matched related (MRD; n = 872) or unrelated (10/10 MUD, n = 1553) or HLA-mismatched unrelated (<10/10 MMUD, n = 790). Overall survival (OS) was similar after MRD compared with 10/10 MUD HSCT, reflecting opposing hazards of relapse (hazard ratio [HR], 1.32; P <.002) and nonrelapse mortality (HR,.63; P <.001). After UD HSCT, increasing HLA disparity was associated with inferior OS (HR, 1.21 [ P <.02] and HR, 1.57 [ P <.001] for 9/10 and ≤8/10 MMUD, respectively, compared with 10/10 MUD). Among non-HLA donor characteristics, age, sex mismatching (male recipient–female donor), and cytomegalovirus (CMV) mismatching (positive recipient–negative donor) impacted OS. Multivariate subgroup analysis showed that OS was similar after HSCT from the youngest 9/10 MMUD (<30 years) compared with the oldest 10/10 MUD (>40 years) (HR, 1.18; P =.25) and also in male patients transplanted from female 10/10 MUD compared with male 9/10 MMUD (HR,.89; P =.46). In contrast, OS of CMV-positive patients tended to be better with CMV-negative 10/10 MUDs compared with CMV-positive 9/10 MMUDs (HR, 1.31; P =.04). Because of low patient numbers in subgroups, definite conclusions and establishment of a hierarchy among HLA matching and non-HLA donor characteristics could not be made. Our data suggest that the impact of donor age and sex mismatch but not CMV mismatch on outcome of allogeneic HSCT may be comparable with that of single HLA disparity. [ABSTRACT FROM AUTHOR]

Background: Despite recent advances in allogeneic hematopoietic stem cell transplantation (AHSCT), the outcome of patients who have acute myeloid leukemia (AML) with a complex karyotype (CK) remains poor. The objective of this study was to identify prognostic factors associated with post-transplantation survival in a large cohort of patients with CK AML.Methods: In total, data on 1342 consecutively patients who underwent transplantation for CK (≥3 chromosomal abnormalities) AML were provided by the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation and from the University of Texas MD Anderson Cancer Center database were included in the analysis. The median patient age was 52 years. The donors were human leukocyte antigen-matched related donors (N = 749), matched unrelated donors (N = 513), and mismatched unrelated donors (N = 80).Results: Relapse was the main cause of treatment failure. Overall, 51% of patients relapsed, 17.6% died of treatment-related mortality, and 31.3% survived leukemia-free. In multivariate analysis, the factors associated with an increased risk of relapse were age (>40 years; hazard ratio [HR], 1.1 per 10 years; P = .02), secondary AML (HR, 1.35; P = .01), active disease at transplantation (HR, 1.98; P < .001), and deletion/monosomy 5 (HR, 1.5; P < .001); whereas age (HR, 1.15 per 10 years; P < .001), secondary AML (HR, 1.36; P = .001), active disease at transplantation (HR, 1.99; P < .001), deletion/monosomy 5 (HR, 1.24; P = .008), and deletion/monosomy 7 (HR, 1.44; P < .001) predicted for leukemia-free survival.Conclusions: Disease relapse remains the most common cause of treatment failure for patients with CK AML after transplantation. Novel approaches to decrease the relapse rate and improve survival are needed in these patients. Cancer 2018;124:2134-41. © 2018 American Cancer Society. [ABSTRACT FROM AUTHOR]

Considering the unsatisfactory results of salvage therapies for patients with relapsed/refractory acute myeloid leukaemia (R/R-AML), their value before allogeneic haematopoietic stem cell transplantation (HSCT) remains questionable. However, direct allogeneic HSCT following established conditioning regimens applied in patients with R/R-AML during active disease has been equally disappointing. In this retrospective observational study, highdose melphalan, as part of a sequential preparative regimen, followed by a total body irradiation (4 × 2 Gy)-based or a treosulfan-based dose-adapted conditioning therapy for allogeneic HSCT was administered to 292 adult patients (median age 56 years, range 17-74) with primary refractory (144 patients), secondary refractory (97 patients) or relapsed AML (51 patients). Overall survival rates at 3 years were 34%, 29% and 41%, respectively. Risk factors associated with an inferior survival were higher age, transplantation from a human leucocyte antigen-mismatched donor and high disease burden. Patients transplanted with blast infiltration <20% showed a notable survival rate of 51% at 3 years. In particular, patients with primary refractory AML showed a more favourable outcome when transplanted early during their disease course. Thus, high-dose melphalan-based sequential conditioning chemotherapy followed by an allogeneic HSCT is feasible and enables long-term remission to be achieved in a substantial proportion of patients with active R/R-AML. [ABSTRACT FROM AUTHOR]

Background: Allogeneic hematopoietic cell transplantation (HCT) is a curative therapy for patients with acute myeloid leukemia (AML). However, post-HCT relapse and regimen-related toxicity remain significant barriers to long-term survival. In recent years, new conditioning regimens have been explored to improve transplantation outcomes in patients with AML. Treosulfan combines a potent immunosuppressive and antileukemic effect with a low toxicity profile.Methods: To investigate the role of treosulfan-based conditioning, the European Society for Blood and Marrow Transplantation Acute Leukemia Working Party performed a registry analysis of 520 adult patients with AML who received treosulfan-based conditioning and underwent HCT between 2000 and 2012, including 225 patients in first complete remission, 107 in second or later complete remission, and 188 with active/advanced disease 188 (88 with primary refractory disease). The median patient age was 57 years (range, 20-73 years). Donors were human leukocyte antigen-identical siblings (n = 187), unrelated donors (n = 235), or mismatched related donors (n = 98). Conditioning regimens included treosulfan (42 g/m2 [n = 396], 36 g/m2 [n = 109], or 30 g/ m2 [n = 15]) with fludarabine or alkylating agents followed by infusion of hematopoietic stem cells (bone marrow, n = 52; peripheral blood, n = 468).Results: At a median follow-up of 61 months, the 5-year overall survival, leukemia-free survival, relapse incidence, and nonrelapse mortality rates were 38%, 33%, 42%, and 25%, respectively. The incidence of grade II-IV acute and chronic graft-versus-host disease was 24% (grade III-V, 11%) and 38%, respectively. Only 11 patients (2%) developed veno-occlusive disease, with two deaths (0.4%) from veno-occlusive disease.Conclusions: Treosulfan-based conditioning regimens provide an acceptable long-term survival with favorable nonrelapse mortality and a very low risk of veno-occlusive disease. Further studies are needed to optimize the treosulfan-based conditioning regimen for patients with AML. Cancer 2017;123:2671-79. © 2017 American Cancer Society. [ABSTRACT FROM AUTHOR]

Background: Allogeneic stem cell transplantation is the only curative option for patients with acute myeloid leukemia (AML) experiencing relapse. Either matched sibling donor (MSD) or unrelated donor (UD) is indicated. Methods: We analyzed 1554 adults with AML transplanted from MSD (n = 961) or UD (n = 593, HLA-matched 10/10, n = 481; 9/10, n = 112). Compared to MSD, UD recipients were older (49 vs 52 years, p = 0.001), transplanted more recently (2009 vs 2006, p = 0.001), and with a longer interval to transplant (10 vs 9 months, p = 0.001). Conditioning regimen was more frequently myeloablative for patients transplanted with a MSD (61 vs 46%, p = 0.001). Median follow-up was 28 (range 3-157) months. Results: Cumulative incidence (CI) of neutrophil engraftment (p = 0.07), grades II-IV acute GVHD (p = 0.11), chronic GVHD (p = 0.9), and non-relapse mortality (NRM, p = 0.24) was not different according to the type of donor. At 2 years, CI of relapse (relapse incidence (RI)) was 57 vs 49% (p = 0.001). Leukemia-free survival (LFS) at 2 years was 21 vs 26% (p = 0.001), and overall survival (OS) was 26 vs 33% (p = 0.004) for MSD vs UD, respectively. Chronic GVHD as time-dependent variable was associated with lower RI (HR 0.78, p = 0.05), higher NRM (HR 1.71, p = 0.001), and higher OS (HR 0.69, p = 0.001). According to HLA match, RI was 57 vs 50 vs 45%, (p=0.001) NRM was 23 vs 23 vs 29% (p = 0.26), and LFS at 2 years was 21 vs 27 vs 25% (p = 0.003) for MSD, 10/10, and 9/10 UD, respectively. In multivariate analysis adjusted for differences between the two groups, UD was associated with lower RI (HR 0.76, p = 0.001) and higher LFS (HR 0.83, p = 0.001) compared to MSD. Interval between diagnosis and transplant was the other factor associated with better outcomes (RI (HR 0.62, p < 0.001) and LFS (HR 0.67, p < 0.001)). Conclusions: Transplantation using UD was associated with better LFS and lower RI compared to MSD for high-risk patients with AML transplanted in first relapse. [ABSTRACT FROM AUTHOR]

Thiotepa is an alkylating compound with an antineoplastic and myeloablative activity and can mimic the effect of radiation. However, it is unknown whether this new regimen could safely replace the longestablished ones. This retrospective matched-pair analysis evaluated the outcome of adults with acute myeloid leukaemia in first complete remission who received myeloablative conditioning either with a thiotepa-based (n = 121) or a cyclophosphamide/total body irradiation-based (TBI; n = 358) regimen for allogeneic hematopoietic stem cell transplantation from an HLA-matched sibling or an unrelated donor. With a median follow-up of 44 months, the outcome was similar in both groups. Acute graft-versus-host disease grade II-IV was observed in 25% after thiotepa-containing regimen versus 35% after TBI (P = 0.06). The 2-yr cumulative incidence of chronic graft-versus-host disease was 40.5% for thiotepa and 41% for TBI (P = 0.98). At 2 yrs, the cumulative incidences of non-relapse mortality and relapse incidence were 23.9% (thiotepa) vs. 22.4% (TBI; P = 0.66) and 17.2% (thiotepa) vs. 23.3% (TBI; P = 0.77), respectively. The probabilities of leukaemia-free and overall survival at 2 yrs were not significantly different between the thiotepa and TBI groups, at 58.9% vs. 54.2% (P = 0.95) and 61.4% vs. 58% (P = 0.72), respectively. Myeloablative regimens using combinations including thiotepa can provide satisfactory outcomes, but the optimal conditioning remains unclear for the individual patient in this setting. [ABSTRACT FROM AUTHOR]

Weight loss and metabolic activity influence outcome after allogeneic stem cell transplantation (alloSCT). This study evaluates pre-conditioning Leptin, a peptide hormone involved in metabolism and immune homeostasis, as a prognostic factor for survival, relapse and non-relapse mortality (NRM) following alloSCT. Leptin serum levels prior to conditioning were determined in a cohort of patients transplanted for various hematologic malignancies (n = 524) and correlated retrospectively with clinical outcome. Findings related to patients with acute leukemia (AL) from this sample were validated in an independent cohort. Low pre-conditioning serum Leptin was an independent prognostic marker for increased risk of relapse (but not of NRM and overall mortality) following alloSCT for AL of intermediate and advanced stage (beyond first complete remission). Multivariate analysis revealed a hazard ratio (HR) for relapse of 0.75 per log2 increase (0.59–0.96, p = 0.020). This effect was similar in an independent validation cohort. Pre-conditioning serum Leptin was validated as a prognostic marker for early relapse by fitting the multivariate Cox model to the validation data. Pre-conditioning serum Leptin levels may serve as an independent prognostic marker for relapse following alloSCT in intermediate and advanced stage AL patients. Prospective studies are required to prove whether serum Leptin could be used for guiding nutritional intervention in patients with AL undergoing alloSCT. [ABSTRACT FROM AUTHOR]

The European LeukemiaNet classification combines a heterogeneous group of aberrations as adverserisk abnormalities. Our goal was to investigate the outcomes associated with distinct highrisk chromosomal abnormalities in acute myeloid leukemia (AML) after allogeneic hematopoietic stem cell transplantation (HSCT). We performed a retrospective cohort analysis in patients with highrisk AML who received first, HLA-compatible, allogeneic HSCT between January 2005 and December 2008. Data from 236 patients with a median age of 55 years were included. Because complex karyotype (CK), -5/5q--, and abnl(17p) are overlapping categories, a hierarchical classification system based on the presence or absence of abnl(17p) and -5/5q- was developed. Patients with abnl(17p) had a 2-year eventfree survival (EFS) of 11% (95% confidence interval [CI], 0%-25%), patients with -5/5q- but no abnl(17p) a 2-year EFS of 29% (95% CI, 14%-44%), and patients with adverserisk AML but neither of the 2 marker lesions a 2-year EFS of 49% (95% CI, 39%-59%). Notably, complex and monosomal karyotypes lost their prognostic value when these marker lesions were excluded. In conclusion, hierarchical classification of adverserisk karyotypes by 2 marker lesions, abnl(17p) and -5/5q-, is effective In prognostication of the outcome of allogeneic HSCT in AML. [ABSTRACT FROM AUTHOR]

Background: As information on incidence, risk factors, and outcome of acute leukemia (AL) relapse after unmanipulated haploidentical stem cell transplantation (haplo-SCT) is scarce, a retrospective registry study was performed by the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation. Methods: Among 1652 transplants performed for lymphoblastic and myeloid AL between 2007 and 2014, 587 patients (acute lymphoblastic leukemia (ALL) 131, acute myeloid leukemia (AML) 456) with detailed information were analyzed aiming to identify risk factors for post-transplant relapse and for overall survival (OS) after relapse. Results: The cumulative incidence of relapse at 3 years was 44% (35–53%) for ALL and 32% (27–36%) for AML (p = 0.023). In ALL, risk factors for relapse were disease status different from the first complete remission (CR1) at haplo-SCT (CR2 vs CR1: HR 2.85, p = 0.011; advanced vs CR1: HR 14.28, p < 0.0001) and male donor gender (HR 3.64, p = 0.0002), while in AML, risk factors were advanced disease at haplo-SCT (advanced vs CR1: HR 3.95, p < 0.0001) and comorbidities (HCT-CI) ≥ 3 (HR 1.75, p = 0.014). Transplants performed in more recent years were associated with lower relapse incidence (RI) in AML, but not in ALL (HR 0.91, p = 0.042). After relapse, median follow-up was 13 months (mos). OS at 1-year post relapse was 18%. Prognostic factors for superior OS after relapse were remission at time of haplo-SCT (CR vs advanced: HR 0.71, p = 0.028), time from transplant to relapse (≥ 5 mos vs < 5 mos: HR 0.530, p < 0.0001), and bone marrow as a stem cell source (peripheral blood (PB) vs bone marrow (BM): HR 1.473, p = 0.016). Conclusions: Risk factors for relapse after haploidentical transplantation were disease specific. Longer OS after relapse was achieved in particular by patients both in CR at haplo-SCT and relapsing more than 5 months after transplant (1-year OS 33%). [ABSTRACT FROM AUTHOR]

Background: Limited data is available to guide the choice of the conditioning regimen for patients with acute myeloid leukemia (AML) undergoing transplant with persistent disease. Methods: We retrospectively compared outcome of fludarabine-treosulfan (FT), thiotepa-busulfan-fludarabine (TBF), and sequential fludarabine, intermediate dose Ara-C, amsacrine, total body irradiation/busulfan, cyclophosphamide (FLAMSA) conditioning in patients with refractory or relapsed AML. Results: Complete remission rates at day 100 were 92%, 80%, and 88% for FT, TBF, and FLAMSA, respectively (p = 0.13). Non-relapse mortality, incidence of relapse, acute (a) and chronic (c) graft-versus-host disease (GVHD) rates did not differ between the three groups. Overall survival at 2 years was 37% for FT, 24% for TBF, and 34% for FLAMSA (p = 0.10). Independent prognostic factors for survival were Karnofsky performance score and patient CMV serology (p = 0.01; p = 0.02), while survival was not affected by age at transplant. The use of anti-thymocyte globulin (ATG) was associated with reduced risk of grade III–IV aGVHD (p = 0.02) and cGVHD (p = 0.006), with no influence on relapse. Conclusions: In conclusion, FT, TBF, and FLAMSA regimens provided similar outcome in patients undergoing transplant with active AML. Survival was determined by patient characteristics as Karnofsky performance score and CMV serology, however was not affected by age at transplant. ATG appears able to reduce the incidence of acute and chronic GVHD without influencing relapse risk. [ABSTRACT FROM AUTHOR]

Background Allogeneic hematopoietic stem cell transplantation (HCT) remains a challenge in elderly and comorbid AML and MDS patients. This patient population is at increased risk for non-relapse mortality (NRM) when treated with standard myeloablative conditioning and was selected to compare a newly developed treosulfan-based with a well-established reduced intensity busulfan-based preparative regimen in a prospective randomized clinical phase III trial. Methods Adult patients with AML in remission or MDS scheduled for HCT from matched related or unrelated donors, aged ≥50 years or with a comorbidity index (HCT-CI) of >2 were enrolled by a central stratified randomization procedure. Treatment arms consisted of intravenous (IV) treosulfan (10 g/m²/day [d-4 to d-2]) or IV busulfan (3.2 mg/kg/day [d-4 to d-3]), both combined with IV fludarabine (30 mg/m²/day [d-6 to d-2]). The primary objective was to compare event-free survival (EFS) at two years with relapse/progression of disease, graft failure, or death reported as events. Secondary endpoints were safety evaluation (according to CTCAE v4.03), engraftment, chimerism, overall survival (OS), relapse/progression incidence (RI), NRM and acute or chronic GvHD. After a previously conducted confirmatory interim analysis (based on 476 patients), which resulted in early termination of patient accrual due to significant non-inferiority of treosulfan treatment with improved EFS, NRM and OS (Beelen et al., ASH 2017), results of the final analysis of all 570 randomized patients including post surveillance data are provided here. Results Median age of the 551 patients (352 AML; 199 MDS) included in the full analysis set (268 treosulfan; 283 busulfan) was 60 years (range: 31, 70). Frequencies of early adverse events (d-6 to d+28) and incidences of acute and chronic GvHD were largely comparable between the two regimens, while extensive chronic GvHD was numerically in favor of treosulfan (19.7% vs. 26.7%; p=0.0750). Primary neutrophil recovery at day +28 was comparable, while the rate of complete donor-type chimerism (day +28) was higher after treosulfan (93.2% vs. 83.3%; p<0.0001). After a median follow-up of 29 months (range: 3.0, 54.3) the 2-year EFS was significantly higher in the treosulfan arm (65.7% vs. 51.2%; hazard ratio [HR] 0.64; p=0.0012) as was OS (72.7% vs. 60.2%; HR 0.64; p=0.0037) and NRM (12.0% vs. 20.4%; HR 0.63; p=0.0343). RI was comparable between both regimens (22.0% vs. 25.2%; HR 0.82; p=0.2631). Results were consistent within all pre-defined major prognostic subgroups of patients. Conclusions Final evaluation of this phase III trial substantiates the previous confirmatory analysis resulting in significantly improved survival after treosulfan-based conditioning. Due to the reduction of NRM a major clinical benefit of the new treosulfan conditioning regimen was demonstrated in the selected AML/MDS patient population. [ABSTRACT FROM AUTHOR]

• Marked improvement has been achieved in recent years in stem cell transplantation (SCT) from unrelated donors. • Long-term outcome is equivalent after SCT from unrelated and sibling donors. • Patients who are leukemia-free 2 years after SCT can expect a favorable outcome. Allogeneic stem cell transplantation (SCT) is potentially curative therapy in acute myeloid leukemia (AML). Marked improvement has been achieved with SCT from matched unrelated donors (MUDs) in recent years. However, there are limited data comparing the long-term outcomes (beyond 10 years) after SCT from sibling donors and MUDs in older patients with AML. We analyzed these outcomes in a large cohort of patients with AML (n = 1134), age ≥50 years, who were alive and leukemia-free 2 years after SCT from matched siblings (n = 848) or MUDs (n = 286), with a median follow-up of 8.9 years. The median age was 56 and 58 years after SCT from siblings and MUDs, respectively (P =.005). In the sibling group, 77%, 12%, and 11% were in first complete remission (CR1), second complete remission (CR2), and active leukemia at SCT compared with 50%, 25%, and 25% in the MUD group, respectively (P <.001). Sixty-one percent of siblings and 62% of MUDs had reduced-intensity conditioning (P =.78). The 10-year leukemia-free survival (LFS) of patients surviving leukemia-free 2 years after SCT was 72% and 62%, respectively (P =.30). Multivariate analysis identified active leukemia at SCT (hazard ratio [HR], 1.86; P =.0001) or CR2 (HR, 1.51; P =.02) compared with CR1, female recipients (HR, 0.71; P =.006), adverse cytogenetics (HR, 2.52; P =.01), and prior graft-versus-host disease (HR, 1.31; P =.04) as independent factors predicting LFS. Donor and conditioning type were not significant. The cumulative incidence was 15% and 17% (P =.97) for late relapse mortality and 13% and 21% for late nonrelapse mortality, respectively (P =.15). In conclusion, long-term LFS is similar, and patients who are leukemia-free 2 years after SCT can expect favorable outcomes with both donor types. [ABSTRACT FROM AUTHOR]

Dose intensity of the conditioning regimen has significant impact on the outcomes after stem cell transplantation (SCT) for acute myeloid leukemia. Most studies have shown more relapse, less nonrelapse mortality (NRM), and similar overall survival after reduced-intensity and myeloablative conditioning. There are limited data on the dose equivalence and expected outcomes of treosulfan-based compared with busulfan-based conditioning. We compared SCT outcomes after fludarabine with either intravenous busulfan at a myeloablative dose (FB4, 12.8 mg/kg, n = 1265) or a reduced dose (FB2, 6.4 mg/kg, n = 1456) or treosulfan at 42 g/m 2 (FT14, n = 403) or 36 g/m 2 (FT12, n = 168). Median patient age was 48, 60, 57, and 60 years in the FB4, FB2, FT14, and FT12 groups, respectively ( P  < .0001). Two-year overall survival was 58%, 53%, 53%, and 51%, respectively ( P  = .25). Multivariate analysis identified advanced age, advanced disease status, and secondary leukemia to be associated with worse survival. Relapse rate was 30%, 35%, 34%, and 40%, respectively. Relapse was more common after FB2, advanced age and disease status, secondary leukemia, and sibling donors. NRM was 17%, 18%, 21%, and 16%, respectively. NRM was least common after FT12 and more common with advanced age and disease status and unrelated donors. Treosulfan-based regimens were associated with lower rates of graft-versus-host disease. There was no difference in any outcome among patients in first complete remission at transplantation. However, there was better survival with treosulfan-based conditioning in advanced leukemia. In conclusion, survival is determined mostly by disease biology and is similar after various regimens. Treosulfan-based conditioning is more similar to myeloablative than to reduced-intensity conditioning but can be administered safely in older patients, with lower rates of graft-versus-host disease and possibly better outcomes in patients with active leukemia. [ABSTRACT FROM AUTHOR]

In this retrospective analysis we evaluated the outcome of 313 patients aged ≥ 70 years in the registry of the European Group for Blood and Marrow Transplantation with myelodysplastic syndrome (MDS; n = 221) and secondary acute myeloid leukemia (n = 92) who underwent allogeneic hematopoietic stem cell transplantation (HSCT) from related (n = 79) or unrelated (n = 234) donors. Median age at HSCT was 72 years (range, 70 to 78). Conditioning regimen was nonmyeloablative (n = 54), reduced intensity (n = 207), or standard intensity (n = 52). Allogeneic HSCT for MDS patients ≥ 70 years was increasingly performed over time. Although during 2000 to 2004 only 16 patients received HSCT, during 2011 to 2013 the number of transplantations increased to 181. The cumulative incidence of nonrelapse mortality at 1 year and relapse at 3 years was 32% and 28%, respectively, with a 3-year overall survival rate of 34%. Good performance, determined by Karnofsky performance status, and recipients' seronegativity for cytomegalovirus was associated with 3-year estimated overall survival rates of 43% ( P  = .01) and 46% ( P  = .002), respectively. Conditioning intensity did not impact survival. After careful patient selection, allogeneic HSCT can be offered to patients older than 70 years with MDS. [ABSTRACT FROM AUTHOR]

Allogeneic hematopoietic cell transplantation is a potentially curative treatment in patients with acute myeloid leukemia. Recent advances in the field of hematopoietic cell allografting have resulted in a practice shift, favoring less intense preparative regimens. We present results of a retrospective comparative analysis of two preparative regimens, namely FB2 (IV fludarabine plus IV busulfan 6.4 mg/kg ± 10%) and FB4 (IV fludarabine plus IV busulfan 12.8 mg/kg ±10%), in patients with acute myeloid leukemia undergoing hematopoietic cell allografting in second complete remission at EBMT participating centers. Between 2003 and 2010, 128 AML patients in second complete remission were allografted following a preparative regimen of FB2 ( n = 88) or FB4 ( n = 40). The median time-to-neutrophil engraftment was similar whether patients received FB2 (16 (5–38) days) or FB4 (16 (9–29) days), p = 0.45. A multivariate analysis showed that use of FB4 resulted in improved 2-year leukemia-free (HR = 0.44 (95%CI = 0.21, 0.94), p = 0.03) and overall survival (HR = 0.38 (95%CI = 0.16, 0.86), p = 0.02). Cumulative incidence of non-relapse mortality (2-year) for all patients was 21% (95%CI = 14–28%). Our analysis suggests that FB4 improves 2-year leukemia-free and overall survival in AML allografted in second complete remission. A confirmatory randomized controlled trial that compares these two preparative regimens (FB2 vs. FB4) in AML in CR2 is definitely warranted. [ABSTRACT FROM AUTHOR]

Standard first-line therapy for older patients with high-risk myelodysplastic syndrome (MDS) includes hypomethylating agents, such as azacitidine (AZA). However, the only approach with curative potential remains allogeneic hematopoietic cell transplantation (HCT). To date, no direct comparison of both strategies has been reported. The outcomes of 2 well-balanced cohorts of patients with high-risk MDS defined by age (60-70 years), performance status (Eastern Cooperative Oncology Group score ≤2), and donor availability (yes/no) were compared, including 103 patients undergoing HCT and 75 patients without this option who received AZA. The estimated 2-year overall survival after the start of treatment was 39% (95% confidence interval, 30%-50%) for the patients undergoing HCT and 23% (95% confidence interval, 14%-40%) for the patients receiving AZA therapy. In a multivariate Cox regression analysis of all patients (n = 178), Eastern Cooperative Oncology Group score (0 versus 1 versus 2; hazard ratio [HR], 2.9/3.9; P <  .001), cytogenetics (good versus intermediate versus poor; HR, 1.2/1.7; P = .026), and treatment (HCT versus AZA; HR, 0.3; P = .007) were associated with overall survival. This retrospective cohort analysis suggests a survival advantage for allogeneic HCT compared with AZA therapy in medically fit patients with high-risk MDS age 60-70 years. Prospective controlled studies are warranted. [ABSTRACT FROM AUTHOR]

The impact of early human cytomegalo-virus (HCMV) replication on leukemic recurrence was evaluated in 266 consecutive adult (median age, 47 years; range, 18-73 years) acute myeloid leukemia patients, who underwent allogeneic stem cell transplantation (alloSCT) from 10 of 10 high-resolution human leukocyte Ag-identical unrelated (n = 148) or sibling (n = 118) donors. A total of 63% of patients (n = 167) were at risk for HCMV reactivation by patient and donor pre-transplantation HCMV serostatus. In 77 patients, first HCMV replication as detected by pp65-antigenemia assay developed at a median of 46 days (range, 25-108 days) after alloSCT. Taking all relevant competing risk factors into account, the cumulative incidence of hematologic relapse at 10 years after alloSCT was 42% (95% confidence interval [Cl], 35%-51%) in patients without opposed to 9% (95% Cl, 4%-19%) in patients with early pp65-antigenemia (P < .0001). A sub- stantial and independent reduction of the relapse risk associated with early HCMV replication was confirmed by multivariate analysis using time-dependent covariate functions for grades II to IV acute and chronic graft-versus-host disease, and pp65-antigenemia (hazard ratio = 0.2; 95% Cl, 0.1-0.4, P < .0001). This is the first report that demonstrates an independent and substantial reduction of the leukemic relapse risk after early replicative HCMV infection in a homogeneous population of adult acute myeloid leukemia patients. [ABSTRACT FROM AUTHOR]

Relapse of acute myelogenous leukemia has been associated with clonal cytogenetic evolution, but no study focused specifically on relapse after allogeneic hematopoietic stem cell transplantation (HSCT). We compared karyotypes in 160 patients at both diagnosis and relapse either after allo-HSCT (n = 26) or standard chemotherapy (n = 134) using chromosome banding analysis combined with fluorescein in situ hybridization. There were 71 females and 89 males (19.7-80.6 years). At diagnosis, aberrant karyotypes were more frequent in the HSCT than in the chemotherapy cohort (16 of 26; 61.5% versus 63 of 134; 47.0%). This was most obvious in patients with unfavorable cytogenetics (8 of 26; 30.8% versus 19 of 134; 14.2%; P = .032). Differences in the karyotypes between diagnosis and relapse were more frequent in the allo-cohort (14 of 26; 53.8% versus 49 of 134; 36.6%) than in the conventional cohort (n.s.), mainly because of newly emerging cytogenetic alterations. Appearance of ≥3 new clonal alterations was more frequent in the allo-cohort (6 of 12; 50.0% with clonal evolution versus 5 of 41; 12.2%, P = .005). The mean number of cytogenetic alterations per patient was increasing from 2.0 at diagnosis to 4.0 at relapse in the allo-cohort, in the conventionally treated patients from 0.9 to 1.3 (both P < .001). Thus, higher frequencies of clonal evolution and increasing cytogenetic complexity were observed in the stem cell recipients probably related to the more unfavorable cytogenetic profiles already depicted at diagnosis. [Copyright &y& Elsevier]

Acute myeloid leukemia bearing a RUNX1 gene mutation (RUNX1 + AML) has been proposed as a provisional entity in the 2016 WHO classification. Clinically, it has been associated with inferior response rates and outcome after conventional chemotherapy. Accordingly, RUNX1 + AML is allocated in the unfavorable prognostic category of the 2017 European Leukemia Net classification. Following allogeneic stem cell transplantation (alloSCT), RUNX1 was an unfavorable factor in one study in MDS/secondary AML, while data in de novo AML are scarce. Here, we present a retrospective study by the EBMT Acute Leukemia Working Party, aiming to elucidate the prognostic value of RUNX1 mutation in patients undergoing alloSCT for AML in first complete remission (CR1). Adults undergoing alloSCT for AML in CR1 from matched related or unrelated donors between 2013 and 2018 with complete information on conventional cytogenetics and RUNX1 mutational status were selected from the EBMT registry. Variables of interest were overall and leukemia-free survival (OS/LFS), GvHD/relapse free survival (GRFS), cumulative relapse incidence (RI), non-relapse mortality (NRM) and GvHD. Log rank test, Gray test and Cox regression models were used. 128 RUNX+ and 388 RUNX- patients were identified, >80% of both subgroups presenting as de novo AML. As expected, RUNX1+ patients rarely had co-mutations in NPM1 (6% vs. 26%, p=10−3), and showed a positive correlation with ASXL1 mutations (50% vs. 16%, p=10−4). Cytogenetic categories and other mutations (FLT3 -ITD, CEBPA) were equally distributed between the two groups, as were age, donor and graft type, CMV, conditioning and T cell depletion (TCD). Median follow-up was 16.4 (RUNX+) and 19.8 (RUNX-) months. 2y OS/LFS of the entire cohort were 64% [59-69]/57% [52-62], with no difference between RUNX1 + and RUNX1 - patients either in univariate or multivariate analysis (2y OS: 67.9% [57.3-78.5] vs. 63.1%v[57.4-68.7]p=0.15; 2y LFS: 57.6% [46.4-68.7] vs. 57% [51.4-62.6], p=0.38], figure 1). RUNX1 mutation neither had any impact among patients with normal karyotype (figure 2). Similarly, no other outcome parameter was influenced by RUNX1 mutational status. Instead, multivariate analysis revealed age and donor type as risk factors for OS, LFS and NRM. Poor cytogenetic was associated with higher RI and inferior LFS/GRFS, in vivo TCD with a lower rate of aGvHD II-IV, cGvHD, and better GRFS. Among patients with available information, FLT3 -ITD was an independent risk factor for relapse, LFS and GRFS. RUNX1 did not modify the role of FLT3 -ITD. Within the limits of a retrospective registry analysis, we could not find a negative influence of RUNX1 mutation on outcome after allogeneic SCT in CR1. Hence, transplantation in CR1 might overcome the unfavorable prognostic value of RUNX1 mutation and can be recommended as consolidation treatment in this entity. [ABSTRACT FROM AUTHOR]

Abstract: Transformed acute myeloid leukemia in myelofibrosis results in a median survival of less than 5 months. We identified 46 of 1048 myelofibrosis patients in the European Group for Blood and Marrow Transplantation registry who received allogeneic stem cell transplantation for acute leukemia evolving from myelofibrosis. The cumulative incidence of treatment-related mortality at 1 year was 28% (95% confidence interval, 14 to 42) and of relapse at 3 years was 47% (95% confidence interval, 31 to 63). The 3-year progression-free (PFS) and overall survival (OS) rates were 26% and 33%, respectively. The only significant factor for survival was complete remission versus no complete remission before transplantation (69% versus 22%, P = .008); however, complete remission was achieved only in 8 patients. Allogeneic stem cell transplantation can cure myelofibrosis patients transformed to leukemia. [Copyright &y& Elsevier]