Reduced intensity conditioning allogeneic hematopoietic cell transplantation for adult acute myeloid leukemia in complete remission - a review from the Acute Leukemia Working Party of the EBMT

Reduced Relapse Incidence with FLAMSA-RIC Compared with Busulfan/Fludarabine for Acute Myelogenous Leukemia Patients in First or Second Complete Remission: A Study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

Busulfan/fludarabine (BuFlu) is a widely used conditioning regimen for patients with myeloid malignancies. The sequential FLAMSA (fludarabine + Ara-C + amsacrine chemotherapy) protocol followed by either cyclophosphamide and total body irradiation (FLAMSA-TBI) or cyclophosphamide and busulfan (FLAMSA-Bu) has shown remarkable activity in high-risk acute myelogenous leukemia (AML) patients. Here we compare the outcomes of AML patients transplanted in first complete remission (CR1) or second complete remission (CR2) after conditioning with BuFlu or FLAMSA. Eligible patients had their first allogeneic stem cell transplantation for AML in CR1 or CR2 between January 2005 and June 2016. Donors were matched related or unrelated with up to 1 mismatch. Conditioning consisted of either BuFlu or FLAMSA. Propensity score matching was applied and comparisons were performed using weighted Cox regression. BuFlu conditioning was used in 1197 patients, whereas FLAMSA-TBI and FLAMSA-Bu were used in 258 and 141 patients, respectively. Median follow-up of survivors was 24.72 months. In univariate analysis, relapse incidence (RI) was 30.3%, 21.9%, and 23.1% in the BuFlu, FLAMSA-TBI, and FLAMSA-Bu groups, respectively (P < .01), and nonrelapse mortality at 2 years was 16.1%, 16.4%, and 26.7%, respectively (P < .01). Leukemia-free survival (LFS) at 2 years was 53.6%, 61.6%, and 50.1%, respectively (P = .03). Weighted Cox regression revealed that FLAMSA-TBI compared with BuFlu was associated with lower RI (hazard ratio [HR], .64; 95% confidence interval [CI], .42 to .98; P = .04) and a trend for better LFS (HR, .72; 95% CI, .49 to 1.06; P = .09). These results suggest that compared with BuFlu, conditioning with FLAMSA-TBI leads to reduced RI at 2 years in AML patients transplanted in CR1 or CR2.

Baseline Renal Function and Albumin are Powerful Predictors for Allogeneic Transplantation-Related Mortality

Biomarkers measured in blood chemistry before allogeneic hematopoietic stem cell transplantation (HSCT) may reflect patients' physiological status. We hypothesized that selected markers are predictive for nonrelapse mortality (NRM) following transplantation and could contribute to risk assessment. We investigated the value of pre-HSCT albumin, estimated glomerular filtration rate (eGFR), and alkaline phosphatase (AlkP) in predicting NRM. We retrospectively analyzed clinical and laboratory data from 1217 patients receiving a first HSCT in 2 European centers between 2003 and 2015. Transplantation indications and conditioning regimens were diverse. Patients had a median age of 55 years and hematopoietic cell transplantation comorbidity index (HCT-CI) scores of 0 (24%), 1 to 2 (39%), and ≥3 (37%). Cutoffs of eGFR <60 mL/min, albumin <3.5 g/dL, and AlkP >180 IU/L corresponded with 8.8%, 8.3%, and 6.5% of the patients, respectively. eGFR and albumin were associated with increased risk and higher cumulative incidence of day-100, 1-year, and 2-year NRM, both as continuous or categorized variables. A similar pattern was observed for AlkP, except for day-100 NRM. In multivariable analyses, eGFR and albumin were consistently among the top risk factors for early and late-term NRM, abrogating the role of age. Prediction models for day-100, 1-year, and 2-year NRM based only on HCT-CI resulted in c-statistics of .565, .575, and .577, respectively. Addition of both biomarkers increased c-statistics for day-100, 1-year, and 2-year NRM to .651, .633, and .624, respectively. Albumin and eGFR are prognostic biomarkers for NRM after HSCT and improve the discriminative power of the HCT-CI.

SupplAzithromycin for Prevention of Graft-Versus-Host Disease: A Randomized Placebo-Controlled Trial

Background: Allogeneic hematopoietic stem cell transplantation has been used widely to treat various types of malignant and non-malignant disorders. Graft-versus-host disease is one of the main complications of this procedure which is associated with considerable mortality and affects quality of life. Despite careful selection of HLA-matched donors and implementing immunosuppressive therapy, the incidence rate of graft-versus-host disease remains high. Macrolide antibiotics are well-known immunomodulatory agents and have been effective as prophylaxis for graft-versus-host disease in preclinical studies. Materials and Methods: Ninety-six adult patients with acute leukemia were recruited into a double-blind, randomized, placebo-controlled trial. All patients were first-time transplant candidates for a full-matched related or unrelated donor. Patients were allocated to receive azithromycin 500 mg daily (n=48) or placebo (n=48) from day -6 to +12. All patients received high-dose chemotherapy, standard immunosuppressive regimen and supportive care according to institutional protocols. Results: The incidence of acute graft-versus-host disease grade III-IV and chronic graft-versus-host disease garde I-III was not significantly different between the two study arms. Oral mucositis grade 1-3 occurred in significantly lower number of patients in the azithromycin group compared with placebo. Conclusion: Based on the results of this study, protective effect of azithromycin on graft-versus-host disease could not be demonstrated.

Mutations in DNMT3A, U2AF1, and EZH2 identify intermediate-risk acute myeloid leukemia patients with poor outcome after CR1

Intermediate-risk acute myeloid leukemia (IR-AML) is a clinically heterogeneous disease, for which optimal post-remission therapy is debated. The utility of next-generation sequencing information in decision making for IR-AML has yet to be elucidated. We retrospectively studied 100 IR-AML patients, defined by European Leukemia Net classification, who had mutational information at diagnosis, received intensive chemotherapy and achieved complete remission (CR) at Cleveland Clinic (CC). The Cancer Genome Atlas (TCGA) data were used for validation. In the CC cohort, median age was 58.5 years, 64% had normal cytogenetics, and 31% required >1 induction cycles to achieve CR1. In univariable analysis, patients carrying mutations in DNMT3A, U2AF1, and EZH2 had worse overall and relapse-free survival. After adjusting for other variables, the presence of these mutations maintained an independent effect on survival in both CC and TCGA cohorts. Patients who did not have the mutations and underwent hematopoietic cell transplant (HCT) had the best outcomes. HCT improved outcomes for patients who had these mutations. RUNX1 or ASXL1 mutations did not predict survival, and performance of HCT did not confer a significant survival benefit. Our results provide evidence of clinical utility in considering mutation screening to stratify IR-AML patients after CR1 to guide therapeutic decisions.

High CD3+ and CD34+ peripheral blood stem cell grafts content is associated with increased risk of graft-versus-host disease without beneficial effect on disease control after reduced-intensity conditioning allogeneic transplantation from matched unrelated donors for acute myeloid leukemia - an analysis from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

Inconsistent results have been reported regarding the influence of graft composition on the incidence of graft versus host disease (GVHD), disease control and survival after reduced-intensity conditioning (RIC) allogeneic peripheral blood stem cell transplantation (allo-PBSCT). These discrepancies may be at least in part explained by the differences in disease categories, disease status at transplant, donor type and conditioning. The current retrospective EBMT registry study aimed to analyze the impact of CD3+ and CD34+ cells dose on the outcome of RIC allo-PBSCT in patients with acute myelogenous leukemia (AML) in first complete remission, allografted from HLA-matched unrelated donors (10 of 10 match). We included 203 adults. In univariate analysis, patients transplanted with the highest CD3+ and CD34+ doses (above the third quartile cut-off point values, >347 x 10^6/kg and >8.25 x 10^6 /kg, respectively) had an increased incidence of grade III-IV acute (a) GVHD (20% vs. 6%, P = .003 and 18% vs. 7%, P = .02, respectively). There was no association between cellular composition of grafts and transplant-related mortality, AML relapse, incidence of chronic GVHD and survival. Neither engraftment itself nor the kinetics of engraftment were affected by the cell dose. In multivariate analysis, CD3+ and CD34+ doses were the only adverse predicting factors for grade III-IV aGVHD (HR = 3.6; 95%CI: 1.45-9.96, P = .006 and 2.65 (1.07-6.57), P = .04, respectively). These results suggest that careful assessing the CD3+ and CD34+ graft content and tailoring the cell dose infused may help in reducing severe acute GVHD risk without negative impact on the other transplantation outcomes.

Voriconazole for prophylaxis of invasive fungal infections after allogeneic hematopoietic stem cell transplantation

INTRODUCTION

Invasive fungal infections (IFIs) following allogeneic hematopoietic stem cell transplantation (alloHSCT) are associated with a high mortality, and accordingly most alloHSCT recipients receive prophylaxis with antifungal agents. Despite some improvement in outcomes of IFIs over time, they continue to represent substantial clinical risk, mortality, and financial burden. Areas covered: We review the main pathogens responsible for IFIs in recipients of alloHSCT, current treatment recommendations, and discuss clinical and economic considerations associated with voriconazole prophylaxis of IFIs in these patients. Expert commentary: The clinical efficacy of voriconazole appears to be at least equivalent to other antifungal treatments, and generally well tolerated. Overall, benefit-risk balance is favorable, and findings from cost-effectiveness analyses support the use of voriconazole prophylaxis of IFIs in recipients of alloHSCT.

Association between anti-thymocyte globulin exposure and survival outcomes in adult unrelated haemopoietic cell transplantation: a multicentre, retrospective, pharmacodynamic cohort analysis

BACKGROUND

Anti-thymocyte globulin (ATG) is used to prevent graft-versus-host disease (GvHD) after allogeneic haemopoietic cell transplantation (HCT). However, ATG can also cause delayed immune reconstitution of T cells, negatively affecting survival. We studied the relation between exposure to ATG and clinical outcomes in adult patients with acute leukaemia and myelodysplastic syndrome.

METHODS

We did a retrospective, pharmacokinetic-pharmacodynamic analysis of data from patients with acute lymphoid leukaemia, acute myeloid leukaemia, or myelodysplastic syndrome receiving their first T-cell repleted allogeneic peripheral blood stem cell HCT with ATG (thymoglobulin) as part of non-myeloablative conditioning from March 1, 2004, to June 1, 2015. Patients received a cumulative intravenous dose of 8 mg/kg divided over 4 days, starting on day -8 before HCT. Active ATG concentrations were measured using a validated bioassay and pharmacokinetic exposure measures (maximum concentration, concentration at time of infusion of the graft, time to reach a concentration of 1 arbitary unit [AU] per day/mL, area under the curve [AUC], and the AUC before and after HCT) were calculated with a validated population pharmacokinetic model. The main outcome of interest was 5-year overall survival, defined as days to death from any cause or last follow-up. Other outcomes were relapse-related mortality, non-relapse mortality, event-free survival, acute and chronic GvHD, and assessment of current and optimum dosing. We used Cox proportional hazard models and Fine-Gray competing risk models for the analyses.

FINDINGS

146 patients were included. ATG exposure after HCT was shown to be the best predictor for 5-year overall survival. Optimum exposure after transplantation was determined to be 60-95 AU per day/mL. Estimated 5-year overall survival in the group who had optimum exposure (69%, 95% CI 55-86) was significantly higher than in the group who had below optimum exposure (32%, 20-51, p=0·00037; hazard ratio [HR] 2·41, 95% CI 1·15-5·06, p=0·020) and above optimum exposure (48%, 37-62, p=0·030; HR 2·11, 95% CI 1·04-4·27, p=0·038). Patients in the optimum exposure group had a greater chance of event-free survival than those in the below optimum exposure group (HR 2·54, 95% CI 1·29-5·00, p=0·007; HR for the above optimum group: 1·83, 0·97-3·47, p=0·063). Above-optimum exposure led to higher relapse-related mortality compared with optimum exposure (HR 2·66, 95% CI 1·12-6·31; p=0·027). Below optimum exposure increased non-relapse mortality compared with optimum exposure (HR 4·36, 95% CI 1·60-11·88; p=0·0040), grade 3-4 acute GvHD (3·09, 1·12-8·53; p=0·029), but not chronic GvHD (2·38, 0·93-6·08; p=0·070). Modelled dosing based on absolute lymphocyte counts led to higher optimum target attainment than did weight-based dosing.

INTERPRETATION

Exposure to ATG affects survival after HCT in adults, stressing the importance of optimum ATG dosing. Individualised dosing of ATG, based on lymphocyte counts rather than bodyweight, might improve survival chances after HCT.

FUNDING

Netherlands Organization for Health Research and Development and Queen Wilhelma Fund for Cancer Research.

miR-34b Targets HSF1 to Suppress Cell Survival in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is the most lethal hematological malignancy, and the occurrence of chemoresistance prevents the achievement of complete remission following the standard therapy. MicroRNAs have been extensively investigated as critical regulators of hematopoiesis and leukemogenesis, and they represent a promising strategy for AML therapy. In this study, we identified miR-34b as a novel regulator in myeloid proliferation and apoptosis of leukemic cells. We found that miR-34b was developmentally upregulated in plasma and myeloid cells of healthy subjects, while it was significantly reduced in blood samples of patients with AML and AML cell lines. Moreover, the miR-34b mimicked transfection-mediated restoration of miR-34b inhibited cell viability and promoted cell apoptosis of HL-60 and OCI-AML3 cell lines. Using a miRNA predicting algorithm miRanda, we selected a potent target heat shock transcription factor 1 (HSF1) since that is a master regulator of the heat shock response and is associated with cancer aggressiveness and dissemination. In contrast to the level of miR-34b, HSF1 was highly expressed in blood samples of patients with AML and AML cell lines. The luciferase reporter assay revealed that miR-34b directly targeted the HSF1 gene. HSF1 silencing exhibited comparable inhibitory effects on AML cell proliferation and survival. The upregulated HSF1 elevated the activation of the Wnt–β-catenin pathway. In conclusion, miR-34b suppressed AML cell proliferation and survival by targeting HSF1, in turn leading to the inactivation of Wnt–β-catenin pathway, which may highlight a new therapeutic approach for AML.

Successful Transfer of Umbilical Cord Blood CD34+ Hematopoietic Stem and Progenitor-derived NK Cells in Older Acute Myeloid Leukemia Patients

Purpose: Older acute myeloid leukemia (AML) patients have a poor prognosis; therefore, novel therapies are needed. Allogeneic natural killer (NK) cells have been adoptively transferred with promising clinical results. Here, we report the first-in-human study exploiting a unique scalable NK-cell product generated ex vivo from CD34⁺ hematopoietic stem and progenitor cells (HSPC) from partially HLA-matched umbilical cord blood units.Experimental Design: Ten older AML patients in morphologic complete remission received an escalating HSPC-NK cell dose (between 3 and 30 × 10⁶/kg body weight) after lymphodepleting chemotherapy without cytokine boosting.Results: HSPC-NK cell products contained a median of 75% highly activated NK cells, with <1 × 10⁴ T cells/kg and <3 × 10⁵ B cells/kg body weight. HSPC-NK cells were well tolerated, and neither graft-versus-host disease nor toxicity was observed. Despite no cytokine boosting being given, transient HSPC-NK cell persistence was clearly found in peripheral blood up to 21% until day 8, which was accompanied by augmented IL15 plasma levels. Moreover, donor chimerism up to 3.5% was found in bone marrow. Interestingly, in vivo HSPC-NK cell maturation was observed, indicated by the rapid acquisition of CD16 and KIR expression, while expression of most activating receptors was sustained. Notably, 2 of 4 patients with minimal residual disease (MRD) in bone marrow before infusion became MRD negative (<0.1%), which lasted for 6 months.Conclusions: These findings indicate that HSPC-NK cell adoptive transfer is a promising, potential "off-the-shelf" translational immunotherapy approach in AML. Clin Cancer Res; 23(15); 4107-18. ©2017 AACR.

Diagnosis and management of AML in adults: 2017 ELN recommendations from an international expert panel

The first edition of the European LeukemiaNet (ELN) recommendations for diagnosis and management of acute myeloid leukemia (AML) in adults, published in 2010, has found broad acceptance by physicians and investigators caring for patients with AML. Recent advances, for example, in the discovery of the genomic landscape of the disease, in the development of assays for genetic testing and for detecting minimal residual disease (MRD), as well as in the development of novel antileukemic agents, prompted an international panel to provide updated evidence- and expert opinion-based recommendations. The recommendations include a revised version of the ELN genetic categories, a proposal for a response category based on MRD status, and criteria for progressive disease.

Impact of Human Leukocyte Antigen Allele Mismatch in Unrelated Bone Marrow Transplantation with Reduced-Intensity Conditioning Regimen

The impact of HLA mismatch in hematopoietic stem cell transplantation with reduced-intensity conditioning (RIC) has not been fully examined. We analyzed a total of 1130 cases to examine the effects of HLA allele mismatch in unrelated bone marrow transplantation (BMT) with RIC in the Japan Marrow Donor Program registry cohort. Compared with HLA 8/8-allele match (n = 720, 8/8 match), both 1 (n = 295, 7/8 match) and 2 allele mismatches (n = 115, 6/8 match) were associated with significant reduction of overall survival (OS) (hazard ratio [HR],  1.34; P = .0024 and HR, 1.33; P = .035 for 7/8 and 6/8 match, respectively). The incidence of grades 2 to 4 acute graft-versus-host disease (aGVHD) increased with increasing number of mismatched alleles (HR, 1.36 and HR, 2.08 for 7/8 and 6/8 match, respectively). Nonrelapse mortality showed a similar tendency to aGVHD (HR, 1.35 for 7/8 and HR, 1.63 for 6/8). One-allele mismatches at the HLA-A or -B and HLA-C loci were significantly associated with inferior OS compared with 8/8 match (HR, 1.64 for A or B mismatch and HR, 1.41 for C mismatch), whereas HLA-DRB1 allele mismatch was not (HR, 1.16; P = .30). However, the effect of HLA-A or -B and -C mismatch on OS was not observed in those who received RIC BMT since 2010, in contrast to recipients before 2010. These results suggested that in unrelated RIC BMT, 1-allele mismatch is associated with poorer outcome, and the impact of HLA mismatch may differ depending on the HLA locus, although these HLA mismatch effects may be different in recent cases.

Sequential Intensified Conditioning Regimen Allogeneic Hematopoietic Stem Cell Transplantation in Adult Patients with Intermediate- or High-Risk Acute Myeloid Leukemia in Complete Remission: A Study from the Acute Leukemia Working Party of the European Group for Blood and Marrow Transplantation

Post-transplant relapse is the leading cause of treatment failure in acute myeloid leukemia (AML) patients after reduced-intensity conditioning allogeneic hematopoietic stem cell transplantation (allo-HSCT). To improve their outcome, we evaluated the outcome of a sequential intermediate-intensity conditioning regimen combining fludarabine, cytosine arabinoside, amsacrine, cyclophosphamide, and either total body irradiation or busulfan (FLAMSA) in patients with intermediate or high-risk AML in first or second complete remission (CR). A total of 265 patients (median age, 55 years; range, 19 to 76) with AML who underwent allo-HSCT using a FLAMSA regimen were included. At the time of transplant, 216 (81.5%) were in CR1 and 49 (18.5%) in CR2. Cytogenetic was intermediate in 114 (43%) and poor in 42 (15.8%) patients, whereas 109 patients (41.1%) had a secondary AML. With a median follow-up of 46 months (range, 1 to 145), the Kaplan-Meier estimate of overall and leukemia-free survival at 2 years were 56.1% (95% CI, 49.7% to 62.6%) and 52.8% (95% CI, 46.4% to 59.2%), respectively. At 2 years, the cumulative incidences of relapse and nonrelapse mortality were 22.8% (95% CI, 17.6% to 28.4%) and 24.0% (95% CI, 18.8% to 29.5%), respectively. In multivariate analysis, patient age and cytogenetics were the only parameters with a significant impact on overall survival. These data suggest that the FLAMSA sequential intermediate conditioning regimen provides an efficient disease control in intermediate- and high-risk AML patients, including those in CR2 and with secondary AML.

The impact of HLA-matching on reduced intensity conditioning regimen unrelated donor allogeneic stem cell transplantation for acute myeloid leukemia in patients above 50 years-a report from the EBMT acute leukemia working party

Background

Data comparing fully matched and mismatched-unrelated-donor (M- and mM-URD) allogeneic hematopoietic stem cell transplant (allo-SCT) following reduced intensity conditioning regimens for acute myeloid leukemia are limited.

Methods

We retrospectively compared the outcome of 3398 patients above the age of 50 years who underwent 10/10 M-URD (n = 2567), 9/10 (n = 723), or 8/10 (n = 108) mM-URD allo-SCT for acute myeloid leukemia after reduced intensity conditioning regimen between 2000 and 2013. The Kaplan-Meier estimator, the cumulative incidence function, and Cox proportional hazards regression models were used where appropriate.

Results

HLA matching had no impact on engraftment (p = 0.31). In univariate analysis, in comparison to 10/10 M-URD, mM-URD was associated with higher incidence of grade II–IV acute graft-versus-host disease (GVHD) (p = 0.0002), similar rates of chronic GVHD (p = 0.138) but increased incidence of its extensive form (p = 0.047). Compared to 10/10 M-URD, patients transplanted in the first complete remission (CR1) with a 9 or an 8/10 mM-URD had decreased 2-year leukemia free (LFS) (p = 0.005) and overall survivals (OS) (56.7, 46.1, and 50.2 %, respectively, p = 0.005), while outcomes were comparable between all groups for patients transplanted beyond CR1. In multivariate analysis, 9/10 versus 10/10 URD was associated with higher non-relapse mortality (HR 1.34, p = 0.001), similar risk of relapse and chronic GVHD and inferior LFS (HR 1.25, p = 0.0001), and OS (HR 1.27, p = 0.0001). There was no difference in adjusted transplant outcomes between 9/10 and 8/10 mM-URD.

Conclusions

Reduced intensity conditioned allo-SCT with a 10/10 M-URD remains the preferable option for AML patients above the age of 50 years. The use of a 9/10 or an 8/10 mM-URD in patients not having a fully matched donor represents an alternative therapeutic option that should be compared to other alternative donor transplant strategies.

Electronic supplementary material

The online version of this article (doi:10.1186/s13045-016-0295-9) contains supplementary material, which is available to authorized users.

Acute myeloid leukemia in the older adults

AML is an aggressive hematological malignancy with highest incidence in the older adults. The adverse features of AML in the elderly, and the frailties and comorbidities frequently present in them, make their management a particularly difficult therapeutic challenge. In this context, it is important to assess carefully patient- as well as disease-associated prognostic features with validated tools. The fittest patients should be considered for curative therapy, such as bone marrow transplantation, whereas low intensity options may be more appropriate for frail patients. Here we review how to assess patients with elderly AML and the treatments options available for them.

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Treatment options remain limited for older adults with AML.

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Nowadays only a tiny proportion of elderly patients with AML undergo HCT.

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The unique features of AML in the elderly urge a fresh approach to these patients.

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Low intensity options may be more appropriate for frail patients.

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Geriatric assessment and social support are critical.

Cardiovascular Complications of Hematopoietic Stem Cell Transplantation

OPINION STATEMENT

Survivors of hematopoietic stem cell transplant (HSCT) are at significant risk for cardiac disease and cardiac complications. While there may be cardiac complications during the acute period of HSCT, long-term survivors remain at risk for cardiovascular disease at a rate at least fourfold higher than the general population. Aggressive screening for cardiac risk factors such as diabetes, hypertension, and arrhythmias is warranted pretransplant. For those with risk factors, particularly a history of cardiovascular disease or atrial fibrillation, cardiology consultation is warranted in the pretransplantation period. Aggressive screening for cardiac risk factors such as diabetes, hypertension, and hyperlipidemia is warranted in HSCT survivors as well; early and aggressive treatment of left ventricular dysfunction is warranted. Collaboration between hematology/oncology and cardiology through a cardio-oncology clinic is an optimal way to help manage these patients.

Expanding transplant options to patients over 50 years. Improved outcome after reduced intensity conditioning mismatched-unrelated donor transplantation for patients with acute myeloid leukemia: a report from the Acute Leukemia Working Party of the EBMT

The outcome of patients undergoing HLA-matched unrelated donor allogeneic hematopoietic cell transplantation following reduced-intensity conditioning or myeloablative regimens is reported to be equivalent; however, it is not known if the intensity of the conditioning impacts outcomes after mismatched unrelated donor transplantation for acute myeloid leukemia. Eight hundred and eighty three patients receiving reduced-intensity conditioning were compared with 1041 myeloablative conditioning regimen recipients in the setting of mismatched unrelated donor transplantation. The donor graft was HLA-matched at 9/10 in 872 (83.8%) and at 8/10 in 169 (16.2%) myeloablative conditioning recipients, while in the reduced-intensity conditioning cohort, 754 (85.4%) and 129 (14.6%) were matched at 9/10 and 8/10 loci, respectively. Myeloablative conditioning regimen recipients were younger, 70% being <50 years of age compared to only 30% in the reduced-intensity conditioning group (P=0.0001). Significantly, more patients had secondary acute myeloid leukemia (P=0.04) and Karnofsky Performance Status score <90% (P=0.02) in the reduced-intensity conditioning group. Patients <50 and ≥50 years were analyzed separately. On multivariate analysis and after adjusting for differences between the two groups, reduced-intensity conditioning in patients age ≥50 years was associated with higher overall survival (HR 0.78; P=0.01), leukemia-free survival (HR 0.82; P=0.05), and decreased non-relapse mortality (HR 0.73; P=0.03). Relapse incidence (HR 0.91; P=0.51) and chronic graft-versus-host disease (HR 1.31; P=0.11) were, however, not significantly different. In patients <50 years old, there were no statistically significant differences in overall survival, leukemia-free survival, relapse incidence, non-relapse mortality, and chronic graft-versus-host-disease between the groups. Our study shows no significant outcome differences in patients younger than 50 years receiving reduced-intensity vs myeloablative conditioning regimens after mismatched unrelated donor transplantation. Furthermore, the data support the superiority of reduced-intensity conditioning regimens in older adults receiving transplants from mismatched unrelated donors.

Hematopoietic stem cell transplantation for patients with AML in first complete remission

Postremission therapy in patients with acute myeloid leukemia (AML) may consist of continuing chemotherapy or transplantation using either autologous or allogeneic stem cells. Patients with favorable subtypes of AML generally receive chemotherapeutic consolidation, although recent studies have also suggested favorable outcome after hematopoietic stem cell transplantation (HSCT). Although allogeneic HSCT (alloHSCT) is considered the preferred type of postremission therapy in poor- and very-poor-risk AML, the place of alloHSCT in intermediate-risk AML is being debated, and autologous HSCT is considered a valuable alternative that may be preferred in patients without minimal residual disease after induction chemotherapy. Here, we review postremission transplantation strategies using either autologous or allogeneic stem cells. Recent developments in the field of alternative donors, including cord blood and haploidentical donors, are highlighted, and we discuss reduced-intensity alloHSCT in older AML recipients who represent the predominant category of patients with AML who have a high risk of relapse in first remission.

Peripheral blood stem cell graft compared to bone marrow after reduced intensity conditioning regimens for acute leukemia: a report from the ALWP of the EBMT

Increasing numbers of patients are receiving reduced intensity conditioning regimen allogeneic hematopoietic stem cell transplantation. We hypothesized that the use of bone marrow graft might decrease the risk of graft-versus-host disease compared to peripheral blood after reduced intensity conditioning regimens without compromising graft-versus-leukemia effects. Patients who underwent reduced intensity conditioning regimen allogeneic hematopoietic stem cell transplantation from 2000 to 2012 for acute leukemia, and who were reported to the Acute Leukemia Working Party of the European Group for Blood and Marrow Transplantation were included in the study. Eight hundred and thirty-seven patients receiving bone marrow grafts were compared with 9011 peripheral blood transplant recipients after reduced intensity conditioning regimen. Median follow up of surviving patients was 27 months. Cumulative incidence of engraftment (neutrophil ≥0.5×10(9)/L at day 60) was lower in bone marrow recipients: 88% versus 95% (P<0.0001). Grade II to IV acute graft-versus-host disease was lower in bone marrow recipients: 19% versus 24% for peripheral blood (P=0.005). In multivariate analysis, after adjusting for differences between both groups, overall survival [Hazard Ratio (HR) 0.90; P=0.05] and leukemia-free survival (HR 0.88; P=0.01) were higher in patients transplanted with peripheral blood compared to bone marrow grafts. Furthermore, peripheral blood graft was also associated with decreased risk of relapse (HR 0.78; P=0.0001). There was no significant difference in non-relapse mortality between recipients of bone marrow and peripheral blood grafts, and chronic graft-versus-host disease was significantly higher after peripheral blood grafts (HR 1.38; P<0.0001). Despite the limitation of a retrospective registry-based study, we found that peripheral blood grafts after reduced intensity conditioning regimens had better overall and leukemia-free survival than bone marrow grafts. However, there is an increase in chronic graft-versus-host disease after peripheral blood grafts. Long-term follow up is needed to clarify whether chronic graft-versus-host disease might increase the risk of late morbidity and mortality.