Myeloid Leukemia In Complete Remission Research Articles

Peripheral blood stem cell versus bone marrow graft for patients ≥60 years undergoing reduced intensity conditioning haploidentical transplantation for acute myeloid leukemia in complete remission: An analysis of the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation.

In the context of T-cell replete haploidentical stem cell transplantation (Haplo-SCT) using post-transplantation cyclophosphamide (PT-Cy), it is still unknown whether peripheral blood (PB) or bone marrow (BM) is the best graft source. While PB is associated with a higher incidence of graft-versus-host disease (GVHD), it may induce a stronger graft-versus-leukemia effect compared to BM, notably in acute myeloid leukemia (AML). From the EBMT registry database, we compared T-cell replete PB (n = 595) versus BM (n = 209) grafts in a large cohort of 804 patients over the age of 60 years who underwent Haplo-SCT with PT-Cy for an AML in first or second complete remission. The risk of acute GVHD was significantly higher in the PB group (Grade II-IV: HR = 1.67, 95% CI [1.10-2.54], p = 0.01; Grade III-IV: HR = 2.29, 95% CI [1.16-4.54], p = 0.02). No significant difference was observed in chronic GVHD or non-relapse mortality. In the PB group, the risk of relapse was significantly lower in the PB group (HR = 0.65, 95% CI [0.45-0.94], p = 0.02) and leukemia-free survival was significantly better (HR = 0.76, 95% CI [0.59-0.99], p = 0.04), with a trend toward better overall survival (HR = 0.78, 95% CI [0.60-1.01], p = 0.06). We conclude that in the specific context of Haplo-SCT with PT-Cy, PB grafts represent a valid option to decrease the risk of relapse and improve outcome of older AML patients who usually do not benefit from conditioning intensification.

Final Results from Phase 1 Study of Briquilimab, an Anti-CD117 Monoclonal Antibody, in Combination with Low Dose Irradiation and Fludarabine Conditioning, Shows Durable Remissions in Older Adults with Acute Myeloid Leukemia in Complete Remission and Myelodysplastic Syndrome Undergoing Allogeneic Hematopoietic Cell Transplantation

Background: Allogeneic hematopoietic cell transplantation (HCT) with non-myeloablative conditioning (NMA) is a potential cure for AML and MDS in older/frail patients. NMA is associated with better tolerability but higher relapse rates compared to more intensive regimens. In a phase 1 study (NCT#04429191), briquilimab (JSP191), a first-in-class monoclonal antibody (mAb) that inhibits stem cell factor binding to CD117 (c-Kit) to deplete hematopoietic stem and progenitor cells (HSPC), in combination with standard NMA conditioning of low dose total body radiation (TBI) and fludarabine (Flu) for HCT, was evaluated in older adults with AML and MDS. Pre-clinical experiments suggest briquilimab synergizes with low dose TBI to deplete normal and malignant HSPC to facilitate donor cell engraftment. Final 1-year efficacy endpoints for all subjects enrolled in this study are presented. Methods: 32 subjects, median age 70 yrs (range 62-79), with AML in morphologic CR (CR1 or CR2+) (n=13), MDS (n=16), or AML not in CR (n =3), and HLA-matched related or unrelated donors were enrolled. Following infusion of briquilimab 0.6 mg/kg, serum levels were assessed to determine start of Flu at 30 mg/m 2/day on Transplant Day (TD)-4, -3, -2, and TBI 2-3 Gy on TD0. Peripheral blood grafts were infused on TD0 (10-14 days after JSP191). GVHD prophylaxis was tacrolimus, sirolimus, and mycophenolate mofetil. Primary endpoints were safety, tolerability, and briquilimab pharmacokinetics. Secondary endpoints included engraftment, chimerism, measurable residual disease (MRD) clearance, acute GVHD (aGVHD), chronic GVHD (cGVHD), NRM, RFS, and OS at 1 year. Results: Summary of main efficacy outcomes is presented in Fig 1. 10 of 13 AML in CR and 14 of 16 MDS subjects had MRD at pre-HCT screening assessed by cytogenetics, flow cytometry, and/or next generation sequencing. There were no infusion toxicities and no briquilimab-related SAEs. Consistent with our previous reports, briquilimab exhibited predictable clearance prior to donor cell infusion, and all subjects engrafted, with neutrophil recovery between TD+19 and TD+26. Compared to baseline marrow, briquilimab alone depleted HSPC with a mean decrease of 62.4±22.7% prior to Flu/TBI (Fig 2). The 28 evaluable subjects at TD+90 achieved median donor myeloid chimerism of 99% (range 96-100%) and median total chimerism of 95% (range 81-100%). There was one secondary graft failure without relapse, who received a 2 nd HCT. Among 13 AML in CR subjects, by 1 year, there were 3 relapses, 1 NRM (GVHD), 9 subjects were alive, and 8 were MRD negative. The 1 subject who was MRD positive at 1 year had only a detectable DNMT3A mutation at low level. 1 of 13 AML in CR subjects had TP53+ disease at screening and this subject was alive and MRD negative at 1 year post-AHCT. Among 16 MDS subjects, by 1 year, there were 5 disease progression/relapses, 1 subject withdrew consent due to persistent disease 3 months post-HCT, 1 NRM (sepsis), 8 subjects were alive, and 6 were MRD negative. 5 of 16 MDS subjects had TP53+ disease, 3 of whom had persistent disease/progressed/relapsed prior to 1 year post-HCT, and the other 2 of whom had MRD positive disease/molecular relapse at 1 year post-HCT. Median time to MRD negativity in all subjects who converted from MRD-positive disease to MRD-negative disease was TD+28. All 3 subjects with AML not in CR had disease progression before 4 months post-AHCT. There was no apparent correlation between level of HSPC depletion at the assessed timepoint (Fig 2) and relapse or survival. Of the 32 enrolled subjects, 4 had MAGIC Grade 2 aGVHD, 1 had MAGIC grade 3-4 aGVHD, 13 had mild/moderate cGVHD, and none had severe cGVHD. Conclusions: These results demonstrate that targeting CD117 with briquilimab together with TBI/Flu as a novel conditioning regimen is safe, well-tolerated, facilitates full donor myeloid chimerism, and sustained clearance of MRD in older adults with AML in CR and MDS without TP53 undergoing NMA AHCT.

Identifying the Optimal Conditioning Intensity of Hematopoietic Stem Cell Transplantation in Patients with Acute Myeloid Leukemia in Complete Remission

Background Allogeneic hematopoietic stem cell transplantation (HSCT) as consolidation therapy is considered a curative option for acute myeloid leukemia (AML) in complete remission (CR) to prevent relapse. Many studies have investigated the optimal conditioning intensity, comparing reduced-intensity conditioning regimen (RIC) and myeloablative conditioning regimen (MAC) for patients with AML in CR. However, inconsistent results have been observed, possibly due to selection biases and significant heterogeneous treatment effects when focusing on average treatment effect. Some studies have attempted to assess treatment effects in specific subgroups, highlighting the heterogeneity conditioning intensity's impact. However, these analyses typically examined one factor at a time, overlooking potential multiple-factor combinations that might contribute to such heterogeneity.To address these limitations and surpass conventional comparison studies and subgroup analyses, machine-learning methods for group identification have been developed. In this study, we aimed to identify patient groups in which MAC or RIC had a superior PFS in patients with AML in CR using a machine-learning approach. Methods Our study included 3273 patients aged 40-69 years with AML in CR from the TRUMP2. These patients were divided into training (N=2020) and validation cohorts (N=1253). In the training cohort, we employed a group identification model to identify patient subsets. Preprocessing of variables was performed to ensure the ease of use in clinical practice. We modeled the magnitude of interaction between treatment and covariates without the main effect of covariates, thus leading to the construction of a scoring system that measures the individualized-treatment effect. The objective variable was set as 1-year PFS, and the interaction effects between treatment and covariates were estimated using a regression model with propensity score weight and LASSO regularization. The sum of the interaction term between treatment and covariates was defined as the “Conditioning Intensity Score”. Patients were categorized into high-score and low-score groups using a cut-off level of median in patients who received RIC. Subsequently, in the validation cohort, we estimated the average treatment effect of RIC compared to MAC for each group with hazard ratios (HR) using inverse treatment probability weight analysis. Results In the training cohort, the median age was 55 years (IQR, 48-61 years), with 1110 (55%) male patients. Among them, 666 (33%) received RIC, while the others underwent MAC. Conditioning Intensity Model was developed and consistent with followings; age over 49 (1.4 points), age over 49 and male (0.8 points), age over 49 and poor karyotype (0.5 point), age over 49 and cord blood transplantation (0.9 points), poor karyotype (-1.6 points), poor karyotype and primary induction failure (8.0 points), poor karyotype and bone marrow transplantation (-5.3 points), cord blood transplantation and hematopoietic cell transplant comorbidity index over 2 (2.1 points) and cord blood transplantation and extra bone marrow involvement (-8.6 points). The cut-off level was set as 2.2. The weighted HR of RIC on 1-year PFS was 0.56 (95%CI; 0.40-0.79, p < 0.001) in the high-score group and 1.23 (95%CI: 0.97- 1.57, p=0.094) in the low-score group. In the entire validation cohort, there were no significant differences in PFS between the RIC and MAC (67.7% [95% CI: 62.1-70.3%] in the RIC group vs. 70.3% [95% CI: 67.2-73.1%] in the MAC group, P=0.318). Patients were divided into two groups based on Conditioning Intensity Score. In the high-score group, the 1-year PFS was 73.9% (95% CI: 65.0-80.9%) in the RIC group vs. 66.2% (95% CI: 58.3-73.0%) in the MAC group ( P=0.181), with a weighted HR of 0.69 (95% CI: 0.43-1.11) for PFS in the RIC group compared to that the MAC group ( P=0.125) (Figure left). Conversely, in the low-score group, the 1-year PFS was 63.7% (95% CI: 56.3-70.2%) in the RIC group vs. 71.2% (95% CI: 67.8-74.2%) in the MAC group ( P=0.031), with a weighted HR of 1.35 (95% CI: 0.96-1.89) in the RIC group compared to the MAC group (log-rank P=0.086) (Figure right). Conclusion In conclusion, we have demonstrated the feasibility of utilizing a machine learning method for subgroup identification of conditioning regimens in patients with AML in CR. This established model holds promise for designing patient-specific regimens.

Weight-adjusted urinary creatinine excretion predicts transplant outcomes in adult patients with acute myeloid leukemia in complete remission

Sarcopenia is a prognostic factor for cancer. Because creatinine is formed from creatine phosphate in muscle tissue, urinary creatinine excretion (UCE) serves as an index of muscle volume. However, as of yet, there are no studies assessing the clinical impact of UCE or weight- adjusted urinary creatinine excretion (WA-UCE) on allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients. We analyzed the association between pre-transplant WA-UCE and transplant outcomes among 164 adult patients with acute myeloid leukemia in complete remission who underwent their first allo-HSCT at our center. The patients were classified into a high (n = 106) and a low WA-UCE group (n = 58) for predicting overall survival (OS) based on the receiver operating characteristics curve. On multivariate analysis, low WA-UCE was associated with poor OS, progression-free survival and a high incidence of non-relapse mortality. WA-UCE has the potential to be an objective biomarker for predicting transplant outcomes, especially the incidence of infection-related death.

IDH1/2 Mutations Are Maintained in a Subset of Patients with Acute Myeloid Leukemia in Complete Remission and Do Not Correlate with Residual Disease

Rationale: Isocitrate dehydrogenase 1 and 2 (IDH1/2) mutations may be the nearest signal to in vivo leukemogenesis that we are able to see in overt acute myeloid leukemia (AML). Without immediate transforming activity and slow, metabolism-related effect, IDH1/2 mutations may be considered within the early events that made a myeloid stem cell a malignant one.Methods: With the aim to investigate the behavior of IDH1/2 mutation in AML patients, we prospectively and longitudinally collected clinical data and samples of DNA extracted from bone marrow of consecutive patients. The study was approved by local Ethical Authority (012/2009/U/Tess, 01/2011/U/Tess, 10/2011/U/Tess and 253/2013/O/Tess). Droplet digital polymerase chain reaction (DdPCR) was performed with Bio-Rad's Qx200 DdPCR System© according manufacture instructions. DdPCR for all the samples were performed in duplicate. Serial dilutions were used to identify sensitivity limit of the method for each mutation included in the study.Results: We analyzed 106 samples from 23 patients (median of 5 samples per patient). At database cut-off, 19th September 2020, median follow-up was 23.8 months (IQR 19.5 - 38.8). Fourteen patients were female. Median age at AML diagnosis was 59 years (IQR: 47.5 - 66). Most of the patients had normal karyotype (15/23, 65%) and 1 patient (4%) received diagnosis of AML after a previous myelodysplastic syndrome. Five out of 22 patients tested (23%) harbored FLT3 ITD, 8/21 (38%) had a NPM1 mutation. Almost the entire population (20/23, 87%) received intensive chemotherapy as induction regimen and 55% of these patients obtained complete remission (CR) after induction. Ten out of 23 patients (45%) harbored an IDH1 mutation, 2/23 (9%) R132G and 8/23 (35%) R132H; 13/23 patients (57%) harbored an IDH2 mutation, 7/23 R172K, 1/23 (4%) R172S and 5/23 (22%) R140Q.Most of the samples were collected in complete remission (CR) (54.5%). Other samples were collected at the time of AML diagnosis (15.1%) or relapse/stable disease (37.3%). Median IDH1/2 fractional abundance was 45.3% (IQR 28.6 - 46.8) at diagnosis, 39.5% (IQR 29.5 - 48.0) at relapse/refractory, and .10 % (IQR: .05 - 17.24) in CR. Few cases showed a fractional abundance below 20% at relapse and only one case was IDH1 negative (during an extramedullary relapse).The fractional abundance of IDH1/2 mutation in CR present a bi-modal trend, allowing us to define 2 groups by k-means stratification. Patients in group 1 (42 samples) tend to have a mutation specific fractional abundance that varies with disease burden (figure B, blue box). On the contrary, at the different time points patients in group 2 (group center 45.58%, 12 samples) have fractional abundance values over 30%, comparable to the levels at diagnosis, even in the absence of any other evidence of AML (figure B, orange box).For NPM1, IDH1/2 positive patients, in 18 timepoints, NPM1 qPCR minimal residual disease (MRD) was compared with IDH1/2 fractional abundance selecting the best possible threshold (best possible threshold .083, predicted sensitivity 75%, predicted specificity 60%; R2= .763, 95% C.I.: .521 - .1.00; asymptotic significance = .062).Finally, we selected 15 patients in which we were able to determine IDH1/2 mutation fractional abundance after induction therapy. Our results indicate that IDH1/2 ddPCR positivity does not impact on prognosis in our patient set.Conclusion: Our study shows that IDH1/2 mutations are maintained throughout time in a subset of patients with IDH1/2 positive AML in CR and that they do not univocally correlate with levels of residual disease. In these AML patients, the persistence of IDH1/2 mutations may be part of a more complex process involving clonal hematopoiesis. In such setting, further studies on the biological and clinical significance of IDH1/2 mutations persistence are warranted. [Display omitted] DisclosuresMartinelli: Abbvie: Consultancy; Astellas: Consultancy, Speakers Bureau; Jazz Pharmaceuticals: Consultancy; Daichii Sankyo: Consultancy; Pfizer: Consultancy, Speakers Bureau; Roche: Consultancy; Celgene /BMS: Consultancy, Speakers Bureau; Incyte: Consultancy; Stemline Therapeutics: Consultancy. Papayannidis: Pfizer, Amgen, Novartis: Honoraria. Cavo: Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Adaptive Biotechnologies: Consultancy, Honoraria; Novartis: Honoraria; GlaxoSmithKline: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel Accommodations, Speakers Bureau; Bristol-Myers Squib: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Curti: Novartis: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Jazz Pharma: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees.

Prognostic value of measurable residual disease at allogeneic transplantation for adults with core binding factor acute myeloid leukemia in complete remission.

Pretransplant measurable residual disease (MRD) has been shown to be associated with relapse incidence following allogeneic hematopoietic cell transplantation (HCT) for acute myeloid leukemia (AML). However, it remains less clear whether pretransplant MRD status affects transplant outcomes in core binding factor AML (CBF-AML). We retrospectively evaluated the effect of pretransplant MRD, which was measured by a polymerase chain reaction of RUNX1-RUNX1T1 or CBFB-MYH11 fusion transcripts, on transplant outcomes for a cohort of 959 adult patients with t(8;21) or inv(16) AML treated by allogeneic HCT during complete remission (CR), between 2000 and 2018. Multivariate analysis showed the absence of pretransplant MRD was significantly associated with lower relapse (hazard ratio [HR], 0.46; P < 0.001), treatment failure (HR, 0.66; P = 0.004), and overall mortality (HR, 0.72; P = 0.037) among patients with t(8;21). However, pretransplant MRD negativity was not associated with relapse (HR, 0.73; P = 0.420), treatment failure (HR, 0.64; P = 0.063), or overall mortality (HR, 0.69; P = 0.149) among patients with inv(16). In subgroup analysis, pretransplant MRD status significantly affected relapse and LFS only in patients with t(8;21) undergoing allogeneic HCT during CR2. In conclusion, our data demonstrate the different prognostic values of pretransplant MRD for CBF-AML, highlighting the need to develop effective therapeutic strategies for such MRD-positive patients.

The path to approval for oral hypomethylating agents in acute myeloid leukemia and myelodysplastic syndromes.

Two oral hypomethylating agents, oral azacitidine (CC-486) and decitabine/cedazuridine (ASTX727), have recently entered the clinical domain. CC-486 has been shown to improve overall survival as maintenance therapy for older patients with acute myeloid leukemia in complete remission, whereas the combination of decitabine with cedazuridine, a cytidine deaminase inhibitor, is indicated for the treatment of adult patients with myelodysplastic syndromes and chronic myelomonocytic leukemia with intermediate-1, or higher, International Prognostic Scoring System risk. This article briefly summarizes the clinical development of both drugs, the pivotal studies that led to their approval and some of the issues faced in extending the use of these drugs to other indications.

Prognostic factors for neutrophil engraftment after haploidentical cell transplantation with PT-Cy in patients with acute myeloid leukemia in complete remission, on behalf of the ALWP-EBMT.

The use of haplo-HCT with posttransplant cyclophosphamide (PT-Cy) is a new standard in the treatment of hematological diseases. A paucity of data exists on risk factors for engraftment failure in haplo-HCT with PT-Cy. We analyzed 1939 adults with acute myeloid leukemia (AML) who received a first haplo-HCT from 2010 to 2019. Status at haplo-HCT was first complete remission (CR1) in 72.5% of patients, secondary AML was reported in 9.9%. Median follow-up was 24.4 months and median age at haplo-HCT was 51 years. Stem cell source was bone marrow (BM) in 42% and peripheral blood stem cell (PBSC) in 58%, and 64% of patients received a myeloablative conditioning (MAC) regimen. Cumulative incidence of primary graft failure (GF) was 6%; GF was reported in 110 patients and 54 died before day +30 with no sign of cell recovery. Overall, 33 patients underwent a second HCT in a median time of 45 days and 13 were alive at last follow-up, the 2-year overall survival (OS) after second HCT being 32.4%. In multivariate analysis, factors independently associated with the risk of nonengraftment were: secondary AML (HR 1.30, p = 0.003), use of RIC (HR 1.22, p < 0.001), and use of BM (HR 1.21, p < 0.001). At 2 years, leukemia-free survival (LFS) and OS for the entire population was 55.2% (95% CI: 52.6-57.6) and 60.9% (95% CI: 58.4-63.3), respectively. Incidence of GF after haplo-HCT with PT-Cy is lower than reported T-cell-depleted haplo-HCT. Optimization of conditioning regimen and graft source should be considered for reducing the risk of GF in haplo-HCT recipients using PT-Cy.

Single Cord Blood Transplantation Versus Unmanipulated Haploidentical Transplantation for Adults with Acute Myeloid Leukemia in Complete Remission

Allogeneic hematopoietic cell transplantation (HCT) is a potentially curative post-remission therapy for adult patients with acute myeloid leukemia (AML) in complete remission (CR). The availability of alternative human leukocyte antigen (HLA)-mismatched donors, such as cord blood and haploidentical related donors, could allow patients to receive allogeneic HCT who are without an HLA-matched sibling or unrelated donor. The use of these alternative donors is preferable for patients with advanced disease due to the rapid availability. However, comparative data for cord blood transplantation (CBT) and haploidentical related donor transplantation (haplo-HCT) are limited for adult patients with AML in CR. We sought to compare overall survival (OS); leukemia-free survival (LFS); graft-versus-host disease (GVHD)-free, relapse-free survival (GRFS); and chronic GVHD-free, relapse-free survival (CRFS) between single-unit CBT (SCBT) and haplo-HCT recipients for adult patients with intermediate- or poor-risk AML in CR. We retrospectively analyzed and compared the results of allogeneic hematopoietic cell transplantation in 1313 adult patients with intermediate- or poor-risk AML in CR who received either SCBT (n = 1102) or unmanipulated haplo-HCT (n = 211) between 2007 and 2018 in Japan. Among the whole cohort, the cumulative incidences of neutrophil and platelet recovery were significantly lower in SCBT recipients compared with those in haplo-HCT recipients (P < .001 for neutrophil, P < .001 for platelet). SCBT was significantly associated with a higher incidence of grade II to IV acute GVHD and lower incidence of extensive chronic GVHD compared to haplo-HCT (P = .013 for grades II to IV acute GVHD; P = .006 for extensive chronic GVHD). Haplo-HCT recipients developed a higher incidence of cytomegalovirus (CMV) antigenemia compared to SCBT recipients (P = .004). In the multivariate analysis, there were no significant differences for grades III or IV acute GVHD (hazard ratio [HR], 1.17; 95% confidence interval [CI], .88 to 1.57; P = .26), relapse incidence (HR, 1.09; 95% CI, .76 to 1.58; P = .61), non-relapse mortality (HR, .83; 95% CI, .58 to 1.18; P = .32), OS (HR, .92; 95% CI, .70 to 1.20; P = .56), LFS (HR, .94; 95% CI, .73 to 1.21; P = .67), GRFS (HR, 1.12; 95% CI, .90 to 1.40; P = .27), or CRFS (HR, 1.15; 95% CI, .92 to 1.44; P = .19) between the two donor types. In the propensity score matching analysis, which identified 180 patients in each cohort, there were no significant differences in transplant outcomes between the two donor types, except for delayed neutrophil (P < .001) and platelet recovery (P < .001) and a higher incidence of grades II to IV acute GVHD (P = .052) in SCBT. SCBT and unmanipulated haplo-HCT had similar survival outcomes for adult patients with AML in CR despite the lower hematopoietic recovery and higher grade II to IV acute GVHD in SCBT recipients and the higher CMV antigenemia in haplo-HCT recipients.

Comparison of mycophenolate mofetil and calcineurin inhibitor versus calcineurin inhibitor-based graft-versus-host-disease prophylaxis for matched unrelated donor transplant in acute myeloid leukemia. A study from the ALWP of the EBMT.

The association of Cyclosporine A (CsA) and mycophenolate mofetil (MMF) has increased in the setting of reduced intensity conditioning (RIC). Nevertheless, the use of CsA or CsA+MMF has not been reported in a large and uniform cohort. We analyzed 497 patients with acute myeloid leukemia in complete remission (CR) who underwent matched unrelated donor (MUD) hematopoietic stem cell transplantation (HSCT). All patients received a fludarabine busulfan RIC regimen and anti-thymocyte globulin (ATG) with either CsA alone or in combination with MMF. The cumulative incidence (CI) of grade II-IV acute GvHD was 27% (95% CI 21-33%) for CsA and 33% (95% CI 27-38%) for CsA+MMF (p = 0.25). The 2-year CI of chronic GvHD was 38% (95% CI 31-45%) and 33% (95% CI 28-39%) for the CsA and the CsA+MMF group, respectively (p = 0.26). On multivariate analysis, no statistically significant differences with respect to relapse incidence (RI), non-relapse mortality (NRM), leukemia-free survival (LFS), overall survival (OS), acute and chronic GvHD were found between the two groups, also when conducting a subgroup analysis in peripheral blood stem cells (PBSC) recipients. Our results support the importance of randomized trial to identify patients who could benefit from the addition of MMF in MUD HSCT.

Azacitidine Maintenance Versus No Maintenance after Standard Therapy in Patientswith Acute Myeloid Leukemia, a Mexican Center Experience

INTRODUCTION Achieving complete remission (CR) is an important goal for patients with acute myeloid leukemia (AML)undergoing treatment with the intent to cure. However, even after consolidation and/or hematopoieticcell transplantation (HCT), many patients will experience disease recurrence. Because of this there has long been an interest in the use of maintenance therapies after the intensive treatment phase to prolong the duration of remission and improve survival and the likelihood of cure. Although the concept of maintenance therapy in AML has been present since the 1960s, it is still a matter of controversy.Azacitidine (AZA) is a hypomethylating agent that acts by incorporating itself into DNA, reversiblyinhibiting DNA methyltransferase, thereby blocking its methylation and activating silenced tumor suppressor genes, resulting in an antitumor effect.Maintenance chemotherapy had not been able to demonstrate improvement in survival. However, in the results of the HOVON-97, Huls et al. showed a 12-month progression free survival (PFS) in 64% of older AML patients who received AZA as maintenance therapy for a maximum of 12 cycles, thus opening the door for new research in this field. OBJECTIVE To know if there is an impact of maintenance treatment with 5-Azacitidine on disease-free survival and progression-free survival, in Acute Myeloid Leukemia in complete remission, in patients who are and are not candidates for bone marrow transplant. PATIENTS AND METHODS We conducted a longitudinal, cohort, analytical, descriptive and single-center study, in the time period between January 2016 and December 2019 (designated the AZA group). Data obtained from patients receiving maintenance was compared with a historic patient cohort (designates as the no-AZA group).This study was approved by the ethics committee of CMN 20 de Noviembre. RESULTS A total of 21 patients were analyzed in the AZA group, of which 53% (n = 12) were women and 37% (n =9) were men, the median age was 54 years with a range of 19 to 65. The median of leukocytes,hemoglobin and platelets of the AZA-group at diagnosis was 22.8x109, 9.3 g/dL, and 44,000 mm3, respectively. Thirty percent had an intermediate cytogenetic risk. In the no-AZA group a total of 18 patients were analyzed, of which 73% (n=11) were female and 26% (n=7) were male, the median age was 57 years with a range of 18 to 64. The median of leukocytes, hemoglobin and platelets at diagnosis was 29.5 x109, 9.5 g/dL, and 57,000 mm3, respectively. In the no-AZA group 8% and 22% had intermediate and high cytogenetic risk, respectively. The median follow up in the no-AZA group was 32 months (10-96). The median of cycles of maintenance with AZA was 12 cycles (1-24); the follow up median, in months, was 19 (range 7-59). The response to maintenance therapy was evaluated after the completion of the first 6 treatment cycles, in which 71.4% maintained a negative minimal residual disease (MRD), and 23.8% experienced a relapse. In the no-AZA group the median time to progression was approximately 8 months, with a PFS median of 15 months; time to progression in the AZA group was approximately 15 months. At the closing of this study the AZA group has not reached the median for PFS (p=0.011) (Figure 1); 42.8% are still in maintenance therapy and in remission, 19% received a bone marrow transplant and are still in remission, 14.4% experienced relapse, 4.8% are in elective suspension of treatment and continue in remission, 9.5% are in observation and palliative care respectively CONCLUSIONS Azacitidine used as maintenance treatment in Acute Myeloid Leukemia can extend progression free survival. Disclosures De La Peña: Janssen:Speakers Bureau;Novartis:Speakers Bureau;Amgen:Speakers Bureau.Alvarez:Amgen:Speakers Bureau;Roche:Speakers Bureau;Celgene:Speakers Bureau;Novartis:Speakers Bureau;Janssen:Speakers Bureau.Perez:Novartis:Speakers Bureau;Roche:Speakers Bureau;Celgene:Speakers Bureau.Alvarado:Novartis:Speakers Bureau;Amgen:Speakers Bureau;Celgene:Speakers Bureau;Alexion:Speakers Bureau;Roche:Speakers Bureau. OffLabel Disclosure: azacitidine as maintenance for AML it is not approved yet in Mexico

Allogeneic hematopoietic cell transplantation efficacy in patients with Philadelphia chromosome-positive acute myeloid leukemia in complete remission.

Philadelphia chromosome-positive acute myeloid leukemia (Ph+ AML) confers a dismal prognosis when treated with chemotherapy alone. Data on allogeneic hematopoietic cell transplantation (allo-HCT) outcomes are limited. We retrospectively analyzed 4649 AML patients who received allo-HCT and were in complete remission. Outcomes of Ph+ AML (n = 30), intermediate-risk, and poor-risk AML patients were compared. The 3-year overall survival after allo-HCT was similar in intermediate-risk (62.7%; 95% CI: 61.0-64.3%) and Ph+ AML (73.3%; 95% CI: 51.5-86.4%) groups (P = 0.42); however, it differed significantly between the poor-risk (49.7%; 95% CI: 45.9-53.4%) and Ph+ AML (73.3%; 95% CI: 51.5-86.4%) groups (P = 0.049). Disease-free survival in Ph+ AML patients was comparable to that in intermediate-risk patients but better than that in poor-risk patients. Relapse rates were significantly lower in Ph+ AML patients than in other groups. Non-relapse mortality (NRM) rates were similar among groups. Multivariate analysis showed that Ph+ AML was not a significant predictor of poor prognosis in terms of overall survival, disease-free survival, relapse, and NRM. Our data showed better post-transplant outcomes for Ph+ AML patients than for those with poor-risk AML. Hence, allo-HCT could be a feasible treatment option for Ph+ AML patients.

Effect of the Thiotepa Dose in the TBF Conditioning Regimen in Patients Undergoing Allogeneic Stem Cell Transplantation for Acute Myeloid Leukemia in Complete Remission: A Report From the EBMT Acute Leukemia Working Party

BackgroundAllogeneic stem cell transplantation is a potentially curative therapy for patients with acute myeloid leukemia (AML) after achieving complete remission (CR). The aim of this study is to evaluate the optimal dose of thiotepa, administered as part of the thiotepa-busulfan-fludarabine (TBF) conditioning regimen for allogeneic stem cell transplantation in adults with AML in CR. Patients and MethodsIn a retrospective multicenter analysis, we identified 240 patients allotransplanted from matched related or unrelated donors or T replete haplo-identical donors. We compared the transplantation outcomes of patients who received 5 mg/kg thiotepa and 2 days of intravenous busulfan at 6.4 mg/kg (T1B2F) versus those who received 10 mg/kg thiotepa with 2 days of intravenous busulfan at 6.4 mg/kg (T2B2F). The median follow-up was 20 months. ResultsOn univariate analysis, the incidence of acute graft versus host disease (GVHD) grade II to IV was significantly lower in the T1B2F group (19%) versus 32% in the T2B2F group (P = .029). This result was confirmed on multivariate analysis; acute GVHD was higher for patients receiving T2B2F (hazard ratio, 2.22; P = .024). No significant change in non-relapse mortality, progression-free survival, or overall survival was observed between the 2 groups. ConclusionT2B2F is associated with a higher incidence of acute GVHD compared with T1B2F. These results suggest that a lower dose-intensity of thiotepa and busulfan in the TBF regimen may yield better results in patients with AML in CR.

Weight Adjusted Urinary Creatinine Excretion Predicts Transplant Outcomes in Adult Patients with Acute Myeloid Leukemia in Complete Remission

Background: Sarcopenia, the loss of muscle mass, has been recognized as a prognostic factor for cancer patients. For example, low body mass index (BMI) was reported to be a risk of poor overall survival (OS) among allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients. However, low BMI was not associated with high non-relapse mortality (NRM) rate, and BMI may not directly reflect the physical condition. (Bone Marrow Transplant. 2014;49:1505-12). To evaluate the clinical impact of the muscle volume on the prognosis of allo-HSCT recipients, other biomarkers that directly reflect muscle mass may be warranted. Urinary creatinine excretion (UCE) has been reported to estimate muscle mass and have prognostic value for kidney transplant patients (Transplantation. 2008;86:391-8.). There is no report to evaluate clinical impact of UCE on the prognosis of allo-HSCT recipients. Therefore, we retrospectively analyzed the association between pre-transplant UCE and the transplant outcomes. Methods: We included 173 adult patients with acute myeloid leukemia (AML) in complete remission (CR) who underwent first allo-HSCT from 2006 to 2017 at our institute and measured UCE before allo-HSCT. Concerned the possibility of urine storage failure, two patients with low total daily urine volume (&lt;0.5L/day) were excluded from this analysis. Therefore, we investigated the remaining 171 patients. In order to correct the physical disparities of individual patients, we evaluated the clinical impact of weight adjusted UCE (WA-UCE) ,i.e UCE / body weight [μmol/kg/day] (Intensive Care Med. 2018;44:1699-708.). We used receiver operating characteristics curve in order to determine the cutoff value of the WA-UCE and classified the patients into the high and low WA-UCE group. We evaluated transplant outcomes such as OS, progression-free survival (PFS), NRM, and cumulative incidence of relapse (CIR) between two groups. Results: The median age at allo-HSCT was 52 (range, 18-73) and there were more male patients (n=111) than female patients (n=60). Regarding cytogenetic risk, 15 (9.1%), 112 (65.8%), and 38 (23.0%) were categorized as favorable, intermediate, and poor risk, respectively (There were five patients without cytogenetic data). The median follow-up period of survivors was 704 (range, 9 to 3,857) days. We defined the cutoff value of the weight adjusted UCE as 148 μmol/kg/day in male and 128 μmol/kg/day in female. Among 171 patients, 90 patients (male = 59, female = 31) were in the high WA-UCE group and 81 patients (male = 52, female = 29) were in the low WA-UCE group. We found no significant differences between two groups in terms of the number of relapse before allo-HSCT, cytogenetic risks, conditioning regimens, hematopoietic cell transplantation comorbidity index, donor-recipient HLA matching, donor source, or estimated glomerular filtration rate. On the other hand, patient's age at allo-HSCT was significantly younger (low vs. high WA-UCE group: median, 53 [range, 18 - 73] vs. 48 [range, 19 - 68] years, P = 0.02) and BMI was lower (low vs. high WA-UCE group: median, 22.3 [range, 15.4 - 38.8] vs. 21.9 [range, 15.4 - 29.3] kg/m2, P = 0.003) in high WA-UCE group. In univariate analysis, we observed a significant difference in OS, PFS, and NRM between two groups (low vs. high WA-UCE group: 1-year OS, 60.1% vs. 80.9%, P &lt; 0.01; 1-year PFS, 54.1% vs. 70.9%, P = 0.02; 1-year NRM, 24.8% vs. 12.3%, P = 0.02) (Figure1). On the other hand, there was no significant difference in 1-year CIR between two groups (low vs. high WA-UCE group: 21.1% vs. 16.8%, P = 0.63). In our cohort, the low BMI (&lt; 18.5 kg/m2) was not significantly associated with OS, PFS, CIR, and NRM (low vs. high BMI group: 1-year OS, 77.6% vs. 69.9%, P = 0.51; 1-year PFS, 74.1% vs. 60.9%, P = 0.45; 1-year CIR, 14.8% vs. 19.5%, P = 0.02, 1-year NRM, 11.1% vs. 19.5%, P = 0.70) In multivariate analysis, the low WA-UCE was an independent risk factor for OS (Hazard ratio (HR) [95% confidence interval (CI)]; 2.29 [1.38 - 3.80], P &lt; 0.01), PFS (HR [95% CI]; 1.76 [1.11 - 2.79], P = 0.02), and NRM (HR [95% CI]; 2.22 [1.13 - 4.36], P = 0.02) (table1). Conclusion: In allo-HSCT adult recipients with AML in CR, low WA-UCE before transplantation was associated with poor prognosis, which related to high NRM within 1 year. WA-UCE can be an independent, objective, simple, and reliable biomarker for evaluating muscle mass and predicting transplant outcome. Disclosures No relevant conflicts of interest to declare.

PF274 UNMANIPULATED HID COMPARED TO MUD AND ISD HAD SIMILAR GRAFT ANTI‐LEUKEMIA EFFECT ON MYELOABLATIVE HSCT FOR AML IN CR

Background:some study has been confirmed more HLA dispariety between donor and patients has a stronger anti‐leukemia effect acute leukemia in some subgroupAims:To identified whether haploidentical donor(HID) have better graft‐versus‐leukemia effects than matched unrelated donor(MUD) and Identical sibling donors(ISD) in allogeneic hematopoietic stem cell transplantation for acute myeloid leukemia in complete remission(CR).Methods:With this background, Between April 2012 and December 2016, consecutive 480 patients with AML in complete remission(CR) who underwent allogeneic HSCT in our center were analyzed retrospectively. donor sources were HID in 316 (65.8%) cases. MUD in 78(16.2%)cases,ISD in 86(17.9%) cases. The median age was 23(range,1.1 to 65) years. Male to female was 263: 217. The median disease course was 8 (range,2 to 57) months. 368(76.6%) cases transplant at CR1 and 112(23.3%) patients at CR2. according to cytogenetic risk stratification,83(17.2%) in poor risk,264(55.0%) in intermediate risk,133(27.7%) in favourable risk.64(13.3%) patients with FLT3‐ITD.Myeloablative conditioning regimens were administered with either Busulfan (Bu) plus Cyclophosphamide (Cy)/Fludarabine (Flu)‐based in 449(93.5%) patients or total body irradiation (TBI) plus Cy/Flu in 31 (6.4%) patients. Antithymocyte globulin was used in MUD and HID‐HSCT. unmanipulated bone marrow(BM) and peripheral blood stem cells (PBSC) for ISD and HID HSCT,only PBSC for MUD transplant were applied as the grafts. GVHD prophylaxis included mycophenolate mofetil(MMF), cyclosporine‐A with short‐term methotrexate for HID and MUD‐HSCT. MMF are not included in ISD‐HSCT.Results:The survivor median follow‐up time were 38(18–74)months, there were similar 5‐year OS (74.7 ± 3.0% vs 86.0 ± 4.3% vs 77.9 ± 4.5%,P = 0.497) and DFS (74.1 ± 3.0% vs 76.6 ± 7.0% vs 76.7 ± 4.6%, P = 0.729)among HID,MUD,ISD‐cohorts.there were no difference relapse(14.3 ± 2.9%vs11.8 ± 7.1%vs9.2 ± 3.3%,P = 0.857) and NRM (13.2 ± 2.0%vs5.3 ± 3.2% vs13.2 ± 2.0%,P = 0.695) among three donor type. We performed univariate analysis the impact of donor type on OS and LFS,relapse in patients at each disease stage such as: patients age(≤18y or 19–40y or&gt;40y), white blood cell at diagnosis (&lt;50 × 109/L or ≥50 × 109/L),cause of disease (primary or sencodary),cytogenetics risk stratification (low or intermediate or high), FLT3‐ITD (with or none),NCCN risk stratification(low or intermediate or high),CRstatus(CR1or CR2),MRD(negative or positive), Extramedullary lesions (with or none), we found no significant differences in OS,LFS,relapse due to donor type. performed multivariate analysis for all patients of pretransplantation variables showed secondary AML, MRD positive were two adverse factor related to OS. MRD positive, HCT‐CI ≥2 were two risk factor associated to DFS. the patients with MRD positive,disease status in CR2,NCCN in higher risk, HCT‐CI ≥2 were associated with cumulative incidence of relapse(CIR).the patients age over 40‐y was only risk factor related to TRM.Summary/Conclusion:HID‐HSCT compared to MUD and ISD had similar graft verse leukemia effect on allo‐HSCT for AML in CR status and on its each disease stage.

Geriatric nutritional risk index (GNRI) just before allogeneic hematopoietic stem cell transplantation predicts transplant outcomes in patients older than 50 years with acute myeloid leukemia in complete remission

Geriatric nutritional risk index (GNRI) just before allogeneic hematopoietic stem cell transplantation predicts transplant outcomes in patients older than 50 years with acute myeloid leukemia in complete remission

Persistence of Exosomes in Patients with Acute Myeloid Leukemia in Complete Remission Suppresses Hematopoiesis

Introduction: Treatment of patients with acute myeloid leukemia (AML) aims at achieving complete remission (CR) and restoration of normal bone marrow function. However, patients who achieve CR following induction chemotherapy often have incomplete count recovery (CRi< 100,000/μL platelets or <1,000/μL neutrophils in the peripheral blood). Patients with CR have better relapse-free survival and overall survival than patients with CRi. Mechanisms by which AML interferes with normal hematopoiesis are under intense investigation. Emerging evidence suggests that blast-derived exosomes suppress hematopoiesis. Exosomes, small (30-150nm) extracellular vesicles, serve as an intercellular communication system. In AML, they shuttle messages between blasts and hematopoietic progenitor cells (HPCs) and reprogram their functions, suppressing hematopoiesis. We hypothesize that exosomes contribute to cytopenias in CRi patients by inhibiting normal hematopoiesis.Methods: Venous blood (20-50 mL) was obtained from 10 patients newly diagnosed with AML prior to therapy and at CR or CRi. Exosomes were isolated from plasma of AML patients and normal donors (n=5) by size exclusion chromatography. Protein levels, numbers and size (qNano), and exosome morphology (transmission electron microscopy) were determined. Exosome cargos were studied by Western blots for Leukemia Associated Antigens and for evidence of proteins involved in hematopoiesis, including dipeptidyllpeptidase-4 (DPP-4/CD26), a serine protease that enzymatically cleaves the proteins regulating hematopoiesis. Effects of exosomes on HPC proliferation and differentiation were evaluated in vitro by colony forming cell (CFC) assays. CFC assays were plated in triplicate. Total CFCs numbers ± exosomes (1-50 µg protein) were determined in the presence/absence of DPP-4 inhibitors.Results: Exosomes isolated from the plasma of AML patients at diagnosis carried Leukemia Associated Antigens, DPP-4, interleukin-3 receptor subunit alpha (CD123), erythropoietin receptor (EPO-R), tumor necrosis factor alpha (TNF-α), and transforming growth factor beta (TGF-β). Blast-derived exosomes at AML diagnosis suppressed the differentiation and proliferation of normal HPCs. The degree of inhibition was exosome dose-dependent. Pharmacologic inhibition of DPP-4 activity reversed suppression of CFC formation (p<0.01). In paired analysis, inhibition of CFC formation by exosomes of the CRi patients remained elevated at levels comparable to those induced by exosomes obtained at AML diagnosis. In contrast, exosomes of CR patients induced lower CFC suppression (p<0.04) than exosomes obtained at AML diagnosis.Conclusion: We report, for the first time, that exosomes in CRi patients inhibit normal human hematopoiesis in vitro. The data implicate AML blast-derived exosomes in suppression of normal hematopoiesis and suggest that in the future reversing the negative effects of exosomes and thus improving platelet and neutrophil counts, might emerge as a new therapeutic approach to AML. DisclosuresNo relevant conflicts of interest to declare.

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.

ABCG2, Cytogenetics, and Age Predict Relapse after Allogeneic Stem Cell Transplantation for Acute Myeloid Leukemia in Complete Remission

Recent studies have shown that ABGG2 protein overexpression in acute myeloid leukemia (AML) may be associated with poor response to therapy and increased relapse risk. Few data are available in patients with AML undergoing allogeneic stem cell transplantation (SCT), particularly when in complete remission (CR). We analyzed 105 patients with AML who underwent allogeneic SCT in CR evaluating the role of ABCG2 and other pretransplantation features on subsequent transplantation outcomes. Factors negatively associated with leukemia-free survival (LFS) were unfavorable cytogenetics (3-year LFS 48% versus 80%, P = .0035) and ABCG2 positivity (65% versus 80%, P = .045). Three-year cumulative incidence of relapse (CIR) in the whole population was 20%; a higher incidence of relapse was associated with adverse cytogenetics (41% versus 16%, P = .018), ABCG2 overexpression (29% versus 15%, P = .04), and, marginally, age > 50 years (30% versus 14%, P = .06). We grouped patients according to the combination of these 3 risk factors: no patient relapsed within 3 years from SCT in the group without risk factors, whereas the 3-year CIR was 12% (95% confidence interval [CI], 2% to 25%) in the group with 1 risk factor and 47% (95% CI, 31% to 70%) in patients with 2 or 3 risk factors (P = .00005). In conclusion, allogeneic SCT does not seem to abrogate the negative prognosis associated with ABCG2 overexpression at diagnosis, specifically in terms of a higher relapse risk. ABCG2, age, and cytogenetics can predict AML relapse after SCT in patients who undergo transplantation while in CR.

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.

Acute myeloid leukemia is the most common indication for an allogeneic hematopoietic cell transplant. The introduction of reduced intensity conditioning has expanded the recipient pool for transplantation, which has importantly made transplant an option for the more commonly affected older age groups. Reduced intensity conditioning allogeneic transplantation is currently the standard of care for patients with intermediate or high-risk acute myeloid leukemia and is now most often employed in older patients and those with medical comorbidities. Despite being curative for a significant proportion of patients, post-transplant relapse remains a challenge in the reduced intensity conditioning setting. Herein we discuss the studies that demonstrate the feasibility of reduced intensity conditioning allogeneic transplants, compare the outcomes of reduced intensity conditioning versus chemotherapy and conventional myeloablative conditioning regimens, describe the optimal donor and stem cell source, and consider the impact of post-remission consolidation, comorbidities, center experience, and more intensive (reduced toxicity conditioning) regimens on outcomes. Additionally, we discuss the need for further prospective studies to optimize transplant outcomes.