High-risk Acute Myelogenous Leukemia Research Articles

Investigating Racially Induced Metabolic and Genomic Signatures Mediating Inferior Survival in African Americans with Acute Myelogenous Leukemia

Background: African American (AA) patients experience worse survival outcomes compared to other patients with acute myelogenous leukemia (AML), independent of socioeconomic and molecular factors. 1 Indeed, our group previously demonstrated inferior survival in AA associated with the proxy for (1) genomic instability and (2) suggestion for inability to achieve protein damaging threshold among concurrent mutations. 2 In study expansion, we have confirmed worse overall survival (OS) for AA patients, and detected rapid attrition of AA patients, soon after diagnosis and therapy initiation. Given high incidence of cardiometabolic complications in AA patients, this prompted us to investigate the link between deranged metabolism and clinical outcomes. Additionally we explored nucleotide modifications that influence leukemogenesis in AA patients. In previous data, obesity correlated with poor outcomes for patients with acute promyelocytic leukemia (APL), but not in other AML, including in the CALGB cohort. 3-5 Interestingly, obesity is linked to 1) FTO/IRX3 pathways that block hematopoietic stem cell differentiation, and 2) oxidative stress, which may induce DNA damage favoring C>A and G>T nucleotide changes 6,7 and aberrant bone marrow microenvironment 8. Methods: We conducted retrospective analysis of 272 AML patients from Baylor TX, Georgetown DC, and Washington Hospital Center DC, including demographic and clinical variables (age, sex, race, BMI, comorbidities, smoking, treatments, and outcomes). APL patients were excluded. For patients with NGS data, mutation frequencies were annotated by ethnicity and prioritized by ELN 2022 classification. Chi-square and t-test evaluated differences in categorical and continuous variables respectively. Logistic binary regression was used to detect predictors for racial induced survival. SAS software was used. Results: Our expanded cohort has 272 AML patients, with 43 AA and 229 non-AA. AA patients showed worse OS than non-AA patients (Fig 1; 149 days vs 605 days, p=0.01). There were not any AA patients with favorable risk ELN 2022 disease status. Neither ELN 2022 risk groups nor presence of MDS-like mutations differentiated worse outcomes for AA patients, so we opted to examine the effect of obesity among AA and non-AA patients with intermediate and high risk AML (given no favorable risk AA patients in our cohort). Mean BMI for our AA patients was 28, with AA patients with BMI>28 showing significantly worse OS (Fig 1; 67 days vs 198 days, p=0.001), which was not present for non-AA patients. Metabolic derangement with high total cholesterol (p=0.02) and LDL (p=0.04) also segregated with worse OS for AAs (n=8 with cholesterol data), but not for other races. Nucleotide changes C>A and G>T characteristic of oxidative stress were overrepresented in AA patients with high BMI suggestive of clinical trend (33% vs 11%, p=0.06). Conclusion: Metabolic derangement in BMI and lipids correlated with inferior outcomes for AA patients only, supporting a unique pathobiology of highly aggressive AML that afflicts AA patients. Only AA patients demonstrated preference for C>A and G>T nucleotide changes, a hallmark of oxidative stress, also linked to obesity. These negative impacts support further mechanistic studies, and may present therapeutic strategies to improve metabolism, reduce oxidative stress, and suppress FTO/IRX3 pathways to induce myeloid differentiation. Figure 1: Inferior Survival For African American Patients Differentiated by BMI>28

High Progression-Free Survival with Low Relapse Rates after Double-Unit Cord Blood Transplantation in Patients with High-Risk AML

Background : Double-unit cord blood transplantation (dCBT) is standard therapy for patients with acute myelogenous leukemia (AML) who do not have suitable adult donors. We & others have reported low relapse rates & high progression free survival (PFS) in dCBT recipients suggesting robust CB-derived graft-versus-leukemia effects. However, the efficacy of dCBT in high-risk AML as determined by ELN genetic risk & pre-transplant minimal residual disease (MRD) status has not been performed to date. Methods : All consecutive adult patients with AML who received first dCBT with intermediate intensity conditioning (Cy50/ Flu150/ Thio10/ TBI400) between 2014-2022 were analyzed. GVHD prophylaxis was with either Cyclosporine-A (CSA)/ Mycophenolate Mofetil (MMF) or CSA/MMF/Tocilizumab on an institutional protocol. Results : 63 patients (pts) (median age 49 years, range 23-63) were eligible for analysis (Table); 42 (67%) were CMV seropositive, 31 (49%) had non-European ancestry, & median HCT-CI was 2 (range 0-6). Most (n = 55, 87%) were in CR1, 5 (8%) in CR2, & 3 were relapsed or primary refractory at transplant (5-9% blasts). By ELN2022 genetic risk criteria, 8 pts had favorable, 29 intermediate, & 20 adverse risk AML (6 were missing ELN status). Of the 60 pts in CR, 36 were MRD- & 18 MRD+ by multicolor flow cytometry (6 had unknown/ indeterminate MRD status). Sixty-one of 63 pts engrafted for a 60-day cumulative incidence of 98% (95%CI:81-100). The median follow-up of survivors was 58 months (range 8-104 months). The 1- & 3-yr incidences of transplant-related mortality (TRM) were 13% (95%CI: 5.9-22) & 18% (95%CI: 9.6-29), respectively. The 1- & 3-year relapse incidences were 3.2% (95%CI: 0.6-9.9) & 8.6% (95%CI: 3.1-18), respectively. The 1- & 3-year OS were 87% (95%CI: 79-96) & 82% (95%CI:72-92) respectively, whereas the 1- & 3-year PFS were 84% (95%CI: 76-94) & 73% (95%CI: 63-85), respectively. When stratified by ELN2022 genetic risk, the 3-year relapse incidence was 0% in favorable, 10% (95%CI: 2.5-25) in intermediate & 13% (95%CI: 2-36%) in adverse risk AML patients. Pts with favorable risk AML had a 3-year PFS of 88% (95%CI: 67-100); the 3-year PFS was similar in patients with intermediate [68% (95%CI: 53-88)] or adverse [67% (95%CI: 48-93)] risk AML (Figure 1A). When stratified by MRD status, the 3-year relapse incidence was 8.4% (95%CI:2.1-20) in MRD- & 13% (95%CI: 1.9-34) in MRD+ patients. The 3-year PFS was similar in patients with AML in CR who were MRD- 80% (95%CI: 68-94) or MRD+ 76% (95%CI: 57-100), whereas all 3 relapsed/ refractory patients died of TRM (Figure 1B). Of 4 TP53-mutated AML patients, one relapsed, one died of TRM, & two are alive in remission. Conclusions: While retrospective, our findings highlight the low relapse rates & promising PFS in adult AML patients, including those with high risk features such as adverse-risk ELN genetic risk &/ or MRD positivity supporting robust CB-derived graft-versus-leukemia (GVL) effects. This observation, together with the mitigation of TRM in recent years due to the optimized transplant practices in adult dCBT (see Politikos et al, ASH 2023), makes intermediate intensity dCBT an attractive strategy for AML patients with a suitable dCB graft & high-risk disease. Our findings warrant prospective multi-center investigation with correlative studies to elucidate the biology of CB-derived GVL.

Comparison of Outcomes after Unrelated Double-Unit Cord Blood and Haploidentical Peripheral Blood Stem Cell Transplantation in Adults with Acute Myelogenous Leukemia: A Study on Behalf of Eurocord and the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

Unmanipulated haploidentical hematopoietic stem cell transplantation (HCT) with post-transplantation cyclophosphamide as graft-versus-host disease (GVHD) prophylaxis (haplo-PTCY) and unrelated double-unit umbilical cord blood transplantation (dUCBT) are feasible options for treating patients with high-risk acute myelogenous leukemia (AML). This study compared outcomes after dUCBT and haplo-HCT using peripheral blood stem cells (PBSCs) in adult patients with AML in complete remission (CR) who underwent transplantation in European Society for Blood and Marrow Transplantation (EBMT)-affiliated centers. In a population of adults with de novo AML in first or second CR, we compared outcomes after dUCBT (n = 165) and after haplo-PTCY PBSC (n = 544) performed between January 2013 and December 2018. Patients receiving in vivo antithymocyte globulin, Campath, or ex vivo T cell depletion were excluded. The median follow-up was 33 months for the haplo-PTCY arm and 52 months for the dUCBT arm. No statistically significant differences were observed between the 2 arms in the rates of grade II-IV acute graft-versus-host disease (GVHD) (hazard ratio [HR], 1.31; P = .18), grade III-IV acute GVHD (HR, 1.17; P = .56), chronic GVHD (HR, .86; P = .48), relapse (HR, 1.07; P = .77), nonrelapse mortality (NRM) (HR, .94; P = .77), leukemia-free survival (LFS) (HR, .99; P = .95), or overall survival (OS) (HR, .99; P = .97). Favorable cytogenetic risk was the sole factor predictive of lower relapse incidence (RI). Younger age at transplantation was associated with lower NRM and higher LFS and OS. Both dUCBT and haplo-PTCY with PBSCs can be considered valid approaches for adult AML patients in CR. New strategies should be investigated in both settings to define the most appropriate conditioning regimen and potentially decrease RI and NRM through better immune reconstitution and optimal supportive care.

P743: THE PIVOTAL ROLE OF GLUTAMINOLYSIS IN MYELODYSPLASTIC SYNDROME (MDS): A NOVEL STRATEGY FOR THE TARGETED THERAPY OF MDS

Background: Myelodysplastic syndromes (MDS) is indicated by bone marrow failure and increased risk of transformation to acute myelogenous leukemia (AML). MDS is more common with advancing age and a combination of comorbidities is associated with significantly worse overall survival. Moreover, iron overload (IOL) starts to develop in MDS patients by transfusion in many cases. Because the outcome of MDS is poor, alternative therapeutic strategies are required to improve the survival of MDS and AML patients. Aims: Glutamine is the most abundant amino acid in blood. Glutaminase (GLS) is the initial enzyme in glutamine metabolism and glutaminolysis contributes to tumor growth. Because GLS is frequently activated in various types of cancer, GLS inhibitor could suppress MDS and AML cells in combination with BCL2 inhibitor. Methods: In this study, we investigated whether GLS was involved in MDS progress. We also investigated the efficacy of GLS inhibitor (CB-839 or IPN-60090) and BCL2 inhibitor, venetoclax by using MDS and AML cell line, SKM-1, MDS-L, MOLM-14, THP-1, MV4;11 and osteoblastic cell line, MC3T3-E1. Results: We first investigated the relationship between GLS expression and MDS patients by microarray gene expression data from the online Gene Expression Omnibus (GEO). In mammalian cells, there are two paralogous GLS genes, GLS1 and GLS2. GLS1 expression was increased in refractory anemia with excess of blasts (RAEB)-2 cells compared to normal control cells (GSE19429). In contrast, GLS2 expression was not changed. High GLS1 expression is associated with poor prognosis in AML patients. Deprivation of glutamine in culture medium revealed that cellular growth inhibition. We next evaluated the effect of GLS inhibitor (CB-839 or IPN-60090) or venetoclax on proliferation of MDS and AML cell lines. 72 h treatment of MDS and AML cells were inhibited by GLS inhibitor or venetoclax in a dose dependent manner. Cellular cytotoxicity and caspase 3/7 activity was also increased. Glutamine is converted by GLS into glutamate and related nicotinamide adenine dinucleotide phosphate (NADP) production. Intracellular NADPH and NADH were reduced by GLS inhibitor. Co-treatment with GLS inhibitor and venetoclax was superior effect than single drug alone. Adenosine triphosphate (ATP) is the most important source of energy for intracellular reactions. Intracellular ATP levels drastically decreased. The bone marrow is a relatively hypoxic microenvironment. Gene expression of GLS1 is increased under hypoxia condition. The proteasome 20S activity and phosphorylation of nuclear factor-kappa B (NF-κB) were increased. Efficacy of venetoclax is reduced under hypoxia condition. Co-treatment with GLS inhibitor and venetoclax overcome in hypoxia mediated drug resistance. GLS1 shRNA transfected cells reduced cellular proliferation. Cell cycle analysis showed G1 arrest and increased sensitivity of venetoclax. Because MDS patients with IOL have reduced overall survival and poorer outcomes, we next examined IOL by using osteoblastic cell line, MC3T3-E1. The cellular proliferation was reduced by ferric ammonium citrate (FAC). Intracellular ROS was increased by FAC. GLS inhibitor treatment protected FAC mediated cell death. Summary/Conclusion: Targeting of glutaminolysis and BCL2 inhibition combine to enhance therapeutic efficacy and has been proposed as a novel strategy high-risk MDS and AML. We also provide the promising clinical relevance as a candidate drug for treatment of MDS and AML patients.

Prophylactic or Preemptive Low-Dose Azacitidine and Donor Lymphocyte Infusion to Prevent Disease Relapse following Allogeneic Transplantation in Patients with High-Risk Acute Myelogenous Leukemia or Myelodysplastic Syndrome

Because of the persistently high rates of relapse of patients with high-risk acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS) following allogeneic hematopoietic stem cell transplantation (allo-HSCT), post-transplantation maintenance therapy has been proposed. We previously initiated a Phase II trial in which epigenetic therapy was combined with immunotherapy in an attempt to reduce disease relapse. In that study, low-dose azacitidine (AZA) and escalating doses of donor lymphocyte infusion (DLI) were given as post-allo-HSCT maintenance treatment. In the present study, we retrospectively analyze a larger cohort of patients receiving post-transplantation maintenance therapy and provide updates on some patients of the earlier study. The objectives of the present study were to analyze the cumulative incidence of relapse (CIR), overall survival (OS), and progression-free survival (PFS) and the incidence of acute and chronic graft-versus-host disease (GVHD) of patients with high-risk AML or MDS receiving post-transplantation maintenance treatment with AZA with or without DLI. We retrospectively analyzed 77 patients (54 with AML, 23 with MDS) considered at high risk based on either their genomic or clinical status at transplantation. Following allogeneic transplantation, they received at least 1 cycle of prophylactic or preemptive low-dose AZA with or without escalating doses of DLI to prevent disease relapse. Almost one-half of the patients (47%) were able to receive the full 12 cycles of scheduled AZA, and a majority (79%) received at least 1 DLI. With a median follow-up of 24 months, 19 patients (25%; 16 with AML, 3 with MDS) relapsed, at a median of 9.8 months (range, 4 to 58.6 months), giving a 22% CIR at 24 months. OS and PFS at 24 months were 70.8% and 68.3%, respectively. The cumulative incidences of grade II-IV acute GVHD and chronic GVHD were 27.4% and 45%, respectively. Only a minority of patients (11%) required delayed administration of AZA. These findings confirm that AZA-DLI maintenance is both tolerable and effective in reducing the risk of post-transplantation relapse.

Geographic Disparities of Hematopoietic Cell Transplantation in Acute Myeloid Leukemia Patients in Virginia

Introduction: Hematopoietic cell transplantation (HCT) is a standard therapy for patients with intermediate to high-risk acute myelogenous leukemia (AML), associated with improved long-term disease-free survival. Virginia is a diverse state, with rural and urban areas, including wealthy and disadvantaged counties. In this study, we compared HCT rates among different regions in the state of Virginia, and analyzed the impact of race/ethnicity, urban vs rural location, primary insurance payor, and socioeconomic status on access to HCT. Methods: We conducted a retrospective, cohort study of patients age 18-75 diagnosed with AML in Virginia from 2013-2017 as reported to the Virginia Cancer Registry (VCR); the VCR was further linked with the Center for International Blood and Marrow Transplant Research (CIBMTR) database for identification of patients who had undergone HCT within two years of diagnosis. Socioeconomic data were generated from the VCR and the American Community Survey (ACS). Univariate and multivariable logistic regression models were used to examine several socioeconomic factors of interest, including patient-level information such as sex, age, race, marital status, primary insurance payor, and distance to closest transplant center as well as factors associated with geography, including specific regions (see Figure 1) and percentage of African Americans residing in the region (see Figure 2). Results: There were 818 patients diagnosed with AML in Virginia from 2013-2017, and of these, 168 (21%) underwent HCT within two years of diagnosis. Median age was lower in the HCT cohort vs. the non-HCT cohort, 55 vs. 64 (p=<0.0001). There was a higher proportion of married patients in the HCT cohort vs. the non-HCT cohort, 67% vs. 53% (p=0.005). The rate of HCT varied by geographic region (p=0.004; see Figure 1). The univariate and multivariate analyses (see Table 1) showed decreased likelihood of HCT with increasing age (OR: 0.96; 95% CI: 0.95-0.98). Patients from regions which had greater than 25% African American population were 42% less likely to undergo HCT (OR: 0.58; 95% CI: 0.38-0.89) (see Figure 2). Patients who were not married were less likely to undergo HCT compared to married patients (OR 0.56; 95% CI: 0.38-0.92). Patients with government insurance as primary payor were less likely to undergo HCT compared to patients with private insurance (OR 0.49; 95% CI: 0.32-0.77). Patients living in areas (by zip code) with a greater percentage of population with a college/graduate degree were more likely to undergo transplant than the patients living in areas with a lower percentage of college/graduate degree (OR: 1.02; 95% CI: 1.00-1.03). Conclusion: From 2013-2017, only 21% of patients with AML in Virginia underwent HCT within two years of diagnosis. We found that the likelihood of undergoing HCT is associated with age, percent of African Americans residing in the region, marital status, primary insurance payor, and percent of population with a bachelor or graduate degree. Our findings suggest geographic and socioeconomic factors are likely barriers to access to HCT. The decreased rate of HCT in regions with a higher percent of African-Americans may reflect structural racism, both due to factors outside and within the medical community. Resources should be devoted to specific interventions addressing disadvantaged populations, including early human leukocyte antigen (HLA) typing, caregiving resources, increased diversity of donor pool, and improved insurance coverage. Future studies will evaluate access to HCT after referral to HCT centers as well as racial disparity in access to HCT across the United States. Disclosures Balkrishnan: Merck and Co.: Consultancy. Devine:Magenta Therapeutics: Consultancy.

Role of Transplant Conditioning Regimen Intensity in High-Risk Acute Myelogenous Leukemia.

Role of Transplant Conditioning Regimen Intensity in High-Risk Acute Myelogenous Leukemia.

The impact of anti-thymocyte globulin on the outcomes of Patients with AML with or without measurable residual disease at the time of allogeneic hematopoietic cell transplantation.

Measurable residual disease (MRD) status pre-allogeneic hematopoietic cell transplantation (allo-HCT) has been shown to predict transplant outcomes. We investigated the effect of Anti-Thymocyte Globulin (ATG) on acute myelogenous leukemia (AML) relapse by pretransplant MRD status. AML patients undergoing allo-HCT in first complete remission from either a matched sibling or unrelated donor during the 2006-2017 period were selected. Outcomes of 1509 patients (MRD+, n = 426) were studied. ATG was used in 561 (52%) and 239 (58%) patients within the MRD- and MRD+ cohorts, respectively. In MRD- patients, ATG did not affect relapse incidence (RI) (HR = 0.80, p = 0.17), but was associated with reduced incidence of grade II-IV acute GVHD, grade II-IV and chronic GVHD, reduced nonrelapse mortality (HR = 0.66, p = 0.05), improved leukemia-free survival (HR = 0.74, p = 0.02), overall survival (HR = 0.69, p = 0.01), and GVHD-relapse free survival (HR = 0.62, p < 0.01). In MRD+ patients, ATG was associated with a lower incidence of chronic GVHD (total, HR 0.56 p = 0.03; extensive, HR 0.40 P = 0.01), without an impact on other allo-HCT outcome parameters, including RI(HR = 1.02, p = 0.92). The use of ATG was associated with reduced risk for GVHD. ATG did not increase RI, even in high-risk AML patients who were MRD+ before allo-HCT.

Hypomethylating Agent Maintenance Therapy after Allogeneic Stem Cell Transplant Improves Transplant Outcome in High Risk Acute Myelogenous Leukemia

Background: Allogeneic hematopoietic stem cell transplant (HSCT) is the only potential curative modality for high risk acute myelogenous leukemia (AML). However, relapse disease remains to be the main reason of failure of allogeneic HSCT. Salvage therapy for relapse AML after allogeneic HSCT is limited and rarely successful. Prognosis is poor with a 2-year survival rate of less than 20%. As majority of relapses occur within first 6 months after transplant, effective preventive intervention given early post allogeneic HSCT may be crucial. An ideal drug for pharmacologic maintenance is difficult to achieve as it should have activity against the disease without excessive myelosuppression or eradication of donor cells, and has minimal or low risk of exacerbation of graft-versus-host disease or additional toxicity. Azacitidine and decitabine are hypomethylating agents (HMAs), which work epigenetically to modulate various genes, including tumor suppressor genes. They have been shown to have benefits in improvement of event free survival and overall survival in relapse AML. Similar benefits have also been reported when low dose azacitadine was given after allogeneic stem cell transplant as a maintenance therapy. Method: This is a single institutional study carried out at the Bone Marrow Transplant Program at the University of Oklahoma Health Science Center. It was started as a case control study in June 2014 when post-transplant azacitadine protocol was initiated, and continues on as a prospective study. Subjects over 18 years old with high risk AML based on cytogenetic and molecular mutation undergoing allogeneic HSCT were enrolled from September 2013 to July 2018. The study is to compare outcome in patients received post-transplant low dose azacitidine at 32mg/m2 on days 1-5 every 28 days for 4 cycles initiating between 6-8 weeks post-transplant versus post-transplant observation. Multivariable cox proportional hazards model was derived to adjust for covariates that differ between the two treatment arms and was used to analyze time to relapse and overall survival in both arms; then our results were graphed using Kaplan Meier Plot. Results: This study included 49 patients undergoing allogeneic HSCT for high risk AML. They were divided into 2 groups with 31 patients received post-transplant azacitidine, and 18 patients did not (prior to initiation of post-transplant azacitadine protocol, control). Our Analysis concluded a greater proportion of deaths among the control group (88.89%) compared to the azacitidine group (25.81%). Majority of deaths in the control group was due to relapse (12 of 16 deaths). Relapse rate was higher in the control group (66.67%) as compared to azacitidine group (25.81%) with statistically significant improvement in time to relapse in the azacitidine group (not reach (NR)) versus 4.1 months in the control arm (log-rank p-value &lt;0.0001) which was described in Figure (1). Median Overall survival was 7.6 months in control arm versus 27.4 months in the 8 patients who relapsed in azacitidine arm (log-rank p-value&lt;0.0001). (Figure 2) Among the 29 subjects from both arms who were relapse-free, overall survival differed between the two treatment groups (log-rank p-value 0.003). Median survival time among those in the control group was 9.8 months. For the azacitidine arm, only 2 events occurred among the 23 relapse-free subjects while the remaining 21 subjects were censored (Figure 3). Among other transplant-related factors, disease status was not differed among the two groups (p=0.411), but conditioning regimen was (p=0.019) with a greater proportion of reduced intensity conditioning (RIC) in the control group (55.56%) than azacitadine group (22.58) (Table 1). After adjusting for conditioning regimen, hazard of relapse was 5.26 (1.99,13.93) times greater (p value&lt;0.001) and death was 5.41 (1.99,13.93) times greater (p value&lt;0.001) in the control group than azacitadine group. In our analysis, cause of death was not statistically significantly different among the two arms (p-value 0.325). Use of azacitidine post-HSCT did not increase the risk of GVHD or infections (table 2). Implications: Low dose azacitidine maintenance therapy after allogeneic stem cell transplant in high risk acute myelogenous leukemia decreases relapse rate, time to relapse and improved overall survival without increasing adverse events and no increased risk of graft-versus-host disease or infections. Disclosures No relevant conflicts of interest to declare.

Liposomal Daunorubicin/Cytarabine As a Bridge to Donor Lymphocyte Infusion or Allogeneic Stem Cell Transplantation for High-Risk Acute Myelogenous Leukemia

Introduction: Liposomal daunorubicin/cytarabine (Vyxeos®) is a dual drug liposomal encapsulation of cytarabine and daunorubicin, delivering drugs at a fixed 5:1 synergistic ratio for a longer therapeutic period. Compared to standard 7+3, liposomal cytarabine/daunorubicin (lipo-cytara/dauno) patients had improved survival and remission rates in a pivotal phase III study of elder adults with high-risk acute myelogenous leukemia (AML). Furthermore, more lipo-cytara/dauno patients went to allogeneic stem cell transplantation (HCT), with lower mortality and improved survival compared to those induced with 7+3. With its enhanced pharmacokinetics, lipo-cytara/dauno may provide a potent bridge to transplant. We report our experience using lipo-cytara/dauno as a bridge to same donor lymphocyte infusion (DLI) or different donor HCT in high-risk AML. Methods: We retrospectively reviewed all patients who received lipo-cytara/dauno at our institution since the FDA approval in August 2017. Of the 21 patients who have been treated, 9 received it as a bridge to cell therapy. All patients received the drug by usual means under the FDA label. Results: The median age of the 9 patients who received lipo-cytara/dauno as a bridge to cell therapy was 59 years. Seven were male, and two were female. Patients had had 1-4 prior lines of chemotherapy (median 2) with 7 of 9 patients having received prior standard 7+3 induction (cytarabine 100-200 mg/m2 x 7 days infusion and daunorubicin 60-90 mg/m2 x 3 days). Most had adverse cytogenetics, and all 9 patients received full lipo-cytara/dauno induction (daunorubicin 44 mg/m2 and cytarabine 100 mg/m2 on Days 1, 3, and 5) as outpatient therapy [Table]. Of the 9 patients, 6 had AML with very early relapse after HCT, with median time to relapse of 4 months (range 3 to 7 months). All 6 successfully proceeded to their planned cell infusion: 5 received same donor DLI after melphalan at 140 mg/m2, and 1 underwent second HCT from a different donor with busulfan/fludarabine conditioning at Days 15-40 after lipo-cytara/dauno. Of the remaining 3, two had relapsed AML after an initial remission (one was in first complete remission (CR1) for 3 months after 7+3/midostaurin induction and the other was in CR1 for 7 months after 7+3 induction/high dose cytarabine consolidation) and one had primary refractory disease (PREF) after 7+3 and azacitidine/venetoclax induction regimens. All 3 successfully underwent first HCT at Days 15-100 days after lipo-cytara/dauno bridge. The PREF patient received fludarabine/cyclophosphamide/TBI conditioning followed by matched unrelated donor transplant. Of the 2 with relapsed AML after initial remission, one received busulfan/fludarabine/thiotepa conditioning followed by umbilical cord stem cell transplantation and the other patient received fludarabine/cyclophosphamide/TBI conditioning prior to matched related donor transplant. Six of 9 had Day 14 bone marrow biopsies after lipo-cytara/dauno: 2 were in CR, 2 had &gt;80% cytoreduction, and 2 had similar blast count. Three with persistent disease underwent reinduction with lipo-cytara/dauno (Days 1 and 3) and proceeded straight to cell therapy after. Median days to hospitalization after outpatient lipo-cytara/dauno was 6 days (range 3 to 14 days). Four out of 9 patients remain alive. Two were very early post HCT relapses (relapsed at 3 and 6 months post-HCT), both of which are remarkably in CR at 14 and 17 months after second cell therapy. Interestingly, both had CNS relapse, which were successfully treated, and both remain alive and in remission today. The other two had relapsed AML and PREF AML and underwent first HCT after lipo-cytara/dauno bridge. They remain alive and in remission at 1 and 8 months. Conclusion: In this retrospective study, outpatient lipo-cytara/dauno as a bridge to cell therapy is feasible and effective in very high-risk AML with no other viable options. While preliminary, survival appears favorable to that reported elsewhere at 14-23% at 1 year in this poor risk group, including those with adverse cytogenetic and/or very early post-HCT relapse. Prospective multi-center trials are planned to further evaluate lipo-cytara/dauno as a bridge to DLI/HCT in those with early relapse post-HCT and in those with refractory disease, with therapy to include CNS prophylaxis. Disclosures Stiff: Gilead/Kite Pharma: Consultancy, Honoraria, Research Funding; Amgen: Research Funding; Gamida-Cell: Research Funding; Incyte: Research Funding; Cellectar: Research Funding; Unum: Research Funding. Tsai:Jazz pharmaceuticals: Speakers Bureau; Jazz pharmaceuticals: Consultancy.

The synergistic antileukemic effects of eltrombopag and decitabine in myeloid leukemia cells.

BackgroundHypomethylating agents (HMAs), such as decitabine (DAC), are currently used as first-line therapy for patients with high-risk myelodysplastic syndromes (MDS) and acute myelogenous leukemia (AML) not eligible for standard chemotherapies. Exacerbation of thrombocytopenia is one of the prevalent complications after HMA treatment. Eltrombopag (EP), an oral thrombopoietin receptor agonist, can efficiently stimulate megakaryopoiesis and elevate platelet counts in MDS/AML patients. However, the significance of combining EP with HMAs in patients with high-risk MDS/AML has not been determined.PurposeTo explore the impacts and mechanisms of EP and/or DAC on leukemia cell growth and to explore whether EP exhibits antileukemic effects in the context of DAC treatment in human myeloid leukemia cell lines.MethodsIn our study, we assessed the anti-leukemic effect of EP in the context of DAC treatment by measuring cell proliferation, apoptosis, cell-cycle distribution, and intracellular reactive oxygen species (ROS) levels.ResultsOur results showed that the combination of EP and DAC had a more obvious antiproliferative effect than that of DAC as a single agent. EP mainly induced S or G0/G1 phase cell cycle arrest, and DAC arrested the cell cycle in the S or G2/M phase. The combination of EP and DAC had a synergistic effect on cell cycle arrest. Furthermore, single-agent treatment with EP or DAC induced a change in intracellular ROS levels, and the combination of EP and DAC had a synergistic effect on ROS levels, exacerbating leukemia cell death.ConclusionOur study provides in vitro evidence of the synergistic antileukemic effect and potential mechanisms of the combination of DAC and EP on myeloid leukemia cells.

Randomized trial comparing standard vs sequential high-dose chemotherapy for inducing early CR in adult AML

AbstractHere we evaluated whether sequential high-dose chemotherapy (sHD) increased the early complete remission (CR) rate in acute myelogenous leukemia (AML) compared with standard-intensity idarubicin-cytarabine-etoposide (ICE) chemotherapy. This study enrolled 574 patients (age, 16-73 years; median, 52 years) who were randomly assigned to ICE (n = 286 evaluable) or sHD (2 weekly 3-day blocks with cytarabine 2 g/m2 twice a day for 2 days plus idarubicin; n = 286 evaluable). Responsive patients were risk-stratified for a second randomization. Standard-risk patients received autograft or repetitive blood stem cell-supported high-dose courses. High-risk patients (and standard-risk patients not mobilizing stem cells) underwent allotransplantation. CR rates after 2 induction courses were comparable between ICE (80.8%) and sHD (83.6%; P = .38). sHD yielded a higher single-induction CR rate (69.2% vs 81.5%; P = .0007) with lower resistance risk (P < .0001), comparable mortality (P = .39), and improved 5-year overall survival (39% vs 49%; P = .045) and relapse-free survival (36% vs 48%; P = .028), despite greater hematotoxicity delaying or reducing consolidation blocks. sHD improved the early CR rate in high-risk AML (odds ratio, 0.48; 95% confidence interval [CI], 0.31-0.74; P = .0008) and in patients aged 60 years and less with de novo AML (odds ratio, 0.46; 95% CI, 0.27-0.78; P = .003), and also improved overall/relapse-free survival in the latter group (hazard ratio, 0.70; 95% CI, 0.52-0.94; P = .01), in standard-risk AML, and postallograft (hazard ratio, 0.61; 95% CI, 0.39-0.96; P = .03). sHD was feasible, effectively achieved rapid CR, and improved outcomes in AML subsets. This study is registered at www.clinicaltrials.gov as #NCT00495287.

Predictive Factors for Complete Remission and Survival in AML Patients Failing to Achieve Adequate Bone Marrow Day 14 Blast Eradication

Introduction: Complete remission (CR) is an important endpoint after cytarabine plus anthracycline [7+3] induction therapy in Acute Myelogenous Leukemia (AML). Even though CR is observed in about 50-90% of unselected European Leukemia Network 2017 (ELN-2017) patients (pt), factors such as age >65 years, complex karyotype, and adverse mutations (RUNX1, ASLX1, TP53, FLT3 ITD high, KMT2A, secondary AML), leads to inadequate blast eradication. Early response to induction is a predictor of subsequent complete remission (CR). Bone marrow day 14 [D14] inform pt with early inadequate leukemia eradication [blast >10%] who are suitable for re-induction, a strategy that seeks to facilitate conversion to CR or CR with incomplete hematologic recovery (CRi), secure potential allogenic transplantation and reproduce superior outcomes. In this study, we investigated the clinical outcome of an unselected ELN-2017 AML cohort with inadequate D14 marrow response. From the subgroup of patients exhibiting sub-optimal response (SOR), we examined the odds and predictors for subsequent achievement of CR/CRi for those patients who did not receiving immediate re-induction therapy. Additionally, we evaluated the effect of subsequent CR/CRi achievement on survival.Methods: With prior IRB approval, 160 AML pt diagnosed with AML from 1995 to 2017 within Baylor College of Medicine institutions were evaluated. Kaplan-Meier method was used to estimate overall survival (OS) among pt achieving D14 <> 10% blast in an unselected ELN-2017 AML cohort and pt exhibiting >10% blast in D14 marrow with and without CR/CRi. Logistic and cox regression analysis in SOR pt [1] attaining subsequent CR/CRi and [2] OS, respectively, was performed to investigate multiple independent variables with predictive value for the 2 above outcomes.Results: 68/160 (42.5%) of pt had available D14 [early assessment] and sequential day 30 marrow for CR/CRi evaluation. Among 68 unselected ELN-2017 AML pt with D14 marrow for CR/CRi assessment, 42/68 (61.7%) and 26/68 (38.2%) had D14 marrow blasts < and > 10%. Median age was 57 y (range 27-73) and 59 y (range 24-89), respectively, p= 0.74. OS was 459 d vs 169 d in pt with D14 marrow <10% and >10%, at day 14 (p=0.001 95% CI 0.2-0.9) [Fig 1A]. CR/CRi was observed in 36/42 (90%) and 10/26 (38.7%) of pt with D14 marrow <10% vs >10%, respectively, p=0.0005. After controlling for traditional high-risk factors including WBC, age, platelet count, RDW, de novo v secondary AML, only ELN-2017 classification [fav vs unfav and intermediate vs unfav, p= 0.0026 and p=0.01] retained impact on survival. In pt with SOR, we performed second analysis to investigate survival among pt with and without subsequent CR/CRi achievement who did not receive re-induction [Fig 1B]. 16/26 (62.5%) of pt with SOR failed to achieved CR/CRi. OS was 333 d vs 109 d for pt with CR/CRi vs those without CR/CRi [p=0.002, 95% CI 2.6-3.4]. Logistic regression identified in pt with CR/CRi vs those without CR/CRi that: [a] age [63.1 vs 43.6 y-p=0.001]; [b] lower platelet count [47.1 vs 83.1 K/uL-p=0.03]; [c] higher absolute monocyte count (AMC) [3.7 vs 0.41 K/uL-p=0.04]; [d] increased RDW [18.3 vs 14.7-p=0.004] and [e] high BMI [31 vs 24.1-p=0.0003] were significantly associated with failure to achieve CR/CRi. Typical complex karyotype and initial marrow blast % were not associated with subsequent CR/CRi achievement. However, in pt with SOR, lack of high-risk mutations [P53, RUNX, FLT3-ITD, U2AF1] was significant associated with CR/CRi, [40% v 62.5%, p= 0.0004]. Cox proportional regression model showed significant impact on survival for high-risk mutations and higher BMI in survival.Conclusion: In our retrospective study, despite 38.7% of patients with detectable D14 residual leukemia achieved CR/CRi without re-induction, failure to attain CR/CRi was frequently observed after SOR. Advanced age, lower platelet count, higher AMC, RDW and BMI predict failure to achieve CR/CRi status in patients exhibiting initial SOR. Lack of high-risk mutation was a strong predictor for CR/CRi achievement. Our study is novel by suggesting that a combination of pre-induction and “early post-induction” variables facilitate recognition of high-risk AML subgroups requiring re-induction or alternative novel therapy via clinical trials. [Display omitted] DisclosuresYellapragada:Takeda: Research Funding; Novartis: Employment; Celgene: Research Funding.

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.

Abstract 5612: Evaluating the cytotoxic effectiveness of a novel TCR-like bispecific T cell engager targeting the PR1/HLA-A2 leukemia antigen

Abstract Overall 5-year survival rates of myeloid leukemia patients remain low at &amp;lt;30%, and new therapies for these patients are desperately needed. PR1 (VLQELNVTV) is a human leukocyte antigen (HLA)-A2 restricted peptide derived from serine proteases proteinase-3 and neutrophil elastase, which are aberrantly expressed in myeloid leukemia blasts, including acute myelogenous leukemia (AML). PR1 was shown to be immunogenic in myeloid malignancies, and we have conducted preclinical development and humanization of a T cell receptor-like monoclonal antibody (h8F4) that targets the leukemia-associated PR1/HLA-A2 complex and eliminates AML xenografts by antibody-dependent cellular cytotoxicity (ADCC) following repeat dosing. To improve the potency of h8F4, we have developed a bispecific T cell-engaging antibody that targets PR1/HLA-A2 on leukemia and CD3 on neighboring T cells. Here we demonstrate successful production and purification of the h8F4 bispecific antibody. Utilizing flow cytometry, we confirm PR1/HLA-A2 and CD3-specific binding characteristics, T cell activation in the presence of PR1/HLA-A2, and importantly AML target cell cytotoxicity after h8F4 bispecific antibody engagement with healthy donor effector T cells. Cytotoxicity assays were performed with both AML cell lines and primary patient AML blasts serving as target cells and health donor PBMC as a source of effector T cells at an E:T ratio of 2:1. Results indicate up to 60% leukemia-specific lysis with 2nM h8F4 bispecific antibody after only 18 hours of incubation. In vivo data also confirm significant elimination of the leukemia cell line U937 (as evidenced by % leukemia cells detected in peripheral blood) in an NSG-U937 AML xenograft mouse model when compared to control groups treated with effector cells alone. Mice were infused with 5,000 leukemia cells followed by 3 million normal healthy donor PBMC. These infusions were followed by a week of daily h8F4 bispecific antibody injections (20ng/injection). Both bioluminescence and flow cytometry analysis two weeks following the final injection show a marked difference between the h8F4 bispecific antibody treatment group and controls, with a 1.5-fold reduction in circulating leukemia cells and an overall increase in survival. In conclusion, these studies demonstrate the therapeutic potential of a novel bispecific antibody targeting the PR1/HLA-A2 leukemia-associated antigen. This bispecific antibody appears to increase the potency of h8F4 with rapid elimination of AML compared to h8F4, and our studies justify potential development as a treatment option for patients with high-risk AML. Citation Format: Amanda Cernosek Herrmann, Jin Seon Im, Hong He, Sergueeva Anna, Sijie Lu, Jeffrey Molldrem. Evaluating the cytotoxic effectiveness of a novel TCR-like bispecific T cell engager targeting the PR1/HLA-A2 leukemia antigen [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5612.

Allogeneic Transplantation for Acute Myelogenous Leukemia in CR1

Allogeneic Transplantation for Acute Myelogenous Leukemia in CR1

Correlation of patient prognosis with PU.1 and JDP2 to provide potential novel prognostic/diagnostic markers in MDS.

e18558 Background: PU.1 is a key transcription factor in haematopoiesis that plays important roles in various haematological malignancies. Previously, significant down-regulation of PU.1 has been reported in high risk myelodysplastic syndrome (MDS) and acute myelogenous leukemia (AML) patients. Methods: To clarify PU.1 molecular function we investigated the gene expression of PU.1 and JDP2 (c-Jun dimerization protein-2), a member of the activating protein-1 family located downstream of PU.1, in bone marrow from 12 MDS patients stratified according to IPSS-R score (6-low, 3-intermediate, 3-high risk), 1 AML patient and 10 normal controls. Samples were enriched for the mononuclear fraction by Ficoll separation. Total RNA was extracted and analysed by Real Time PCR for PU.1 and JDP2 expression relative to the housekeeping gene GAPDHusing the 2-ΔΔCT method. Results: We revealed both PU.1 and JDP2 are down regulated in MDS. In addition, our data suggests that PU.1 and JDP2 expression inversely correlates with disease, with expression of these genes consistently reducing according to IPSS-R groups. Furthermore, a positive correlation of PU.1 and JDP2expression &lt; R = O.9333, s = 0.0004 &gt; , provides additional evidence that suppression of JDP2 by PU.1 could contribute to the pathogenesis of AML. Notably, PU.1 and JDP2 do not correlate to the same extent in normal HSCs, indicating that cofactors are required for PU.1 to exert its JDP2-regulating function and that such cofactors are not present under normal conditions. To confirm that JDP2 suppression is a direct result of reduced PU.1 we performed PU.1-knockdown in K562 cells stably expressing PU.1 short interfering RNAs versus control cells. These analyses reveal only a partial reduction in JDP2 expression when analysed by RT-PCR and Western blot, suggesting a more complex regulatory mechanism. Additionally, both PU.1 and JDP2 expression was recovered by treatment with azacitidine, which is routinely used to treat MDS, suggesting an involvement in treatment response. Conclusions: PU.1 and JDP2 expression correlates with patients prognosis highlighting a potential role as new diagnostic and prognostic markers in MDS.

69 - Maintenance Therapy with Azacitadine and Valproic Acid after Allogeneic Stem Cell Transplant in Patients with High-Risk Acute Myelogenous Leukemia

69 - Maintenance Therapy with Azacitadine and Valproic Acid after Allogeneic Stem Cell Transplant in Patients with High-Risk Acute Myelogenous Leukemia

Cellular Immunotherapies for Leukemia Patients

Cellular Immunotherapies for Leukemia Patients

Cellular immune profiling after sequential clofarabine and lenalidomide for high risk myelodysplastic syndromes and acute myeloid leukemia

Patients with high risk myelodysplastic syndromes (MDS) and acute myelogenous leukemia (AML) are commonly older with multiple co-morbidities, rendering them unsuitable for intensive induction chemotherapy or transplantation. We report preliminary cellular immune profiling of four cases receiving sequential clofarabine and lenalidomide for high risk MDS and AML in a phase I study. Our results highlight the potential of immune profiling for monitoring immune-modifying agents in high risk MDS and AML.