Poor-risk Acute Myeloid Leukemia Research Articles

A Comparison of Somatic Mutations and ELN Classification in De Novo Acute Myeloid Leukemia between Appalachian and Non-Appalachian Kentucky

Introduction The Appalachian region's cancer mortality rate is 10% higher than the national rate. Central Appalachia, which is predominantly in Kentucky, exceeds the national average by 35%. Appalachian Kentucky has higher mortality rates for prostate, lung, cervical, and head and neck cancers compared to non-Appalachian Kentucky. This can be attributed to health care disparities, environmental factors, and unique genomic characteristics of the tumors seen in the Appalachian population. Based on this, we hypothesized that patients with acute myeloid leukemia (AML) in Appalachian Kentucky would have worse outcomes and higher mutational burden compared to patients in non-Appalachian Kentucky. To test this hypothesis, we compared overall survival (OS) and frequency of molecular mutations between patients from Appalachian (ApK) and Non-Appalachian Kentucky (Non-ApK). Methods A single-center retrospective analysis was done utilizing the Kentucky Cancer Registry (KCR) to identify patients with De Novo AML from January 2015 to January 2021. Patients with available cytogenetic and somatic mutations profile from next-generation sequencing (NGS) were included. Demographic, clinical, laboratory, and pathologic data were obtained from clinical records. Statistical analysis was done using the Mann-Whitney U test for continuous variables and proportions were compared using Chi-square test. The Kaplan-Meier curves were used for overall survival. Results A total of 225 patients with de novo AML were identified. The median age at diagnosis was 61 (range, 21-86). The population was fairly distributed among males (52%) and females (48%). Approximately 56% (n=127) of patients were from ApK and 46% (n=98) were from non-ApK. Of the patients from ApK, approximately 22% (n=29) had favorable risk AML per the ELN 2022 classification, while 24% (n=30) had intermediate and 54% (n=68) had poor risk AML. This was not statistically different from the Non-ApK patients where 22% (n=22) had favorable, 21% (n=21) had intermediate, and 56% (n=55) of patients had poor risk AML (Table 1). The median number of clinically significant mutations were also similar between the two groups (p value = 0.47). The most commonly occurring somatic mutations were NPM1, DNMT3A and FLT3-ITD, which occurred at similar frequencies between the ApK and non-ApK cohorts. There was no difference in the median overall survival between the two cohorts (17 versus 22 months, p =0.47; 90% CI). Median OS and 1-year OS for the entire cohort were 21 months and 47.1%, respectively. Conclusions This study demonstrated that the outcomes of de novo AML is similar for patients from Appalachian versus Non-Appalachian Kentucky when treated at an Academic Medical Center. There were no statistically significant differences between ELN 2022 risk classification and mutational abnormalities tested between these two groups. This suggests that the biology in de novo AML is similar in both ApK and non-ApK patients.

Allele-Specific Expression of Leukemia Genes Is Associated with Pathogenicity in Poor Risk AML

Introduction: An imbalance in gene expression of the different alleles of a gene (allele-specific expression or ASE) is an intriguing genome-wide and dynamic phenomenon that could have an important role in tumorigenesis. Little is known about the causes and consequences of the differential cis- and trans-regulation on resultant ASE, aside from the impact of copy number alterations (CNAs) or imprinting. Acute myeloid leukemia (AML) is an aggressive clonal hematopoietic stem cell malignancy, with a low mutational burden in comparison with other cancers, where the impact of ASE may constitute a novel mechanism of pathogenesis. Aim: Application of Whole Genome Sequencing (WGS), RNA-seq and Oxford Nanopore methylation sequencing to study the ASE landscape in a cohort of poor risk AML patients and shed light on the mechanisms triggering this phenomenon as well as its temporal dynamics. Methods: ASE landscape was explored using paired germline and tumour WGS and RNA-seq on diagnostic bone marrow or peripheral blood samples from 33 cytogenetically poor risk AML patients, and additional RNA-seq from 18 samples corresponding to follow-up timepoints (including remission, relapse and refractory samples) from eight of the patients.Heterozygous SNPs were identified in the genomic DNA, and allele frequencies in RNA-seq reads were used to quantify ASE, after filtering for CNAs in the tumor DNA. Cas9-enriched Oxford Nanopore sequencing was then performed on available patient samples at diagnosis and subsequent time points. Allele-specific methylation was determined on the Nanopore sequencing using Guppy v6.3. Results: In the diagnostic cohort, we identified 4,802 protein-coding genes exhibiting ASE in at least one sample, with a median of 169 genes per sample (range 119-468, with one outlier sample showing ASE in 1,705 genes). Overall, 283 protein-coding genes showed ASE in ≥ 20% patients across the 33 samples. These genes included known imprinted genes and the transcription factor GATA2, where ASE was previously associated with AML, validating our ASE pipeline and filtering criteria. We also identified for the first time recurrent ASE in other myeloid genes such as KMT2A (20%), the homeobox genes PBX2 (41%), PBX3 (20%), HOXA6 (20%) and HOXB cluster ( HOXB2 (31%), HOXB3 (27%), HOXB5 (40%), HOXB6 (30%)); and the myeloid differentiation genes CDKN2A (40%), PDGFRB (25%) and PRTN3 (57%). Eighteen primary AML samples from 8/33 patients had paired diagnostic, remission and relapse or refractory material, allowing us to track the dynamic ASE pattern. RNA-seq and Sanger sequencing of cDNA in these samples showed that the ASE observed at diagnosis in HOXB2, HOXB3, HOXB6, PBX3 and GATA2 was lost in the corresponding remission sample (bi-allelic expression), with ASE returning at relapse and maintained in the refractory samples. In order to explore the epigenetic mechanisms underlying these allele-specific changes in expression, Cas9-enriched Oxford Nanopore sequencing was performed in 2 patients with available DNA at diagnosis and sequential time points, to determine the pattern of allele-specific methylation of the promoter region of GATA2 (patient 1) and HOXB2 (patient 2). In patient 1 at diagnosis, 90% of CpG sites were methylated at the GATA2 promoter region on one allele versus 61% in the other allele, with the hypomethylated allele corresponding to the allele that is overexpressed in the ASE sample. However, in the remission sample, the proportion of methylated CpG sites on the two alleles was similar (83% and 73%, respectively), in agreement with the expression of both GATA2 alleles at this stage. Likewise, in the diagnostic sample of patient 2, 6% of CpG sites were methylated in the HOXB2 promoter region of one allele, corresponding to the overexpressed allele in the ASE sample, while the other promoter allele had 17% of CpG sites methylated; with no differences in CpG methylation between alleles in the remission samples (9% versus 9%), again correlating with the bi-allelic expression of HOXB2 at remission. Conclusions: Combining WGS and RNA-seq in AML primary samples, we have identified key leukemia genes showing recurrent dynamic ASE associated with disease evolution: since it is found at diagnosis, lost in remission, but recovered in relapse and persisting in refractory stages. Our results also suggest allele-specific methylation as the potential mechanism orchestrating this phenomenon.

Comparison of Autologous, Matched Sibling, and Alternative Donor Stem Cell Transplant Outcomes for Acute Myeloid Leukemia Patients in First Remission: A Propensity Score Matching Study

Introduction Autologous hematopoietic stem cell transplantation (auto-HSCT), matched sibling donor HSCT (MSD-HSCT), and alternative donor HSCT (AD-HSCT) are viable post-remission treatment options for acute myeloid leukemia (AML). Auto-HSCT is more commonly administered in favorable- and intermediate-risk AML with good remission, while MSD-HSCT and AD-HSCT are suggested for patients with high-risk factors. In the present study, we aim to retrospectively compared auto-HSCT with MSD-HSCT and AD-HSCT in de novo AML patients who are in first complete remission (CR1) with favorable or intermediate risk, according to 2022 ELN criteria. Methods We conducted a single-center retrospective comparative analysis, comparing auto-HSCT and allo-HSCT for favorable and intermediate-risk de novo AML in CR1. Patients with secondary AML, acute promyelocytic leukemia, poor-risk AML, those receiving syngeneic HSCT, those not in CR1 before HSCT, or those who achieved CR1 with ≥ 3 cycles of induction chemotherapy were excluded from the study. A total of 283 de novo favorable- and intermediate-risk AML patients, based on the ELN 2022 criteria, in first complete remission were initially included for propensity score matching. Persistent undetectable MRD (uMRD) was defined as uMRD after one course of chemotherapy without recurrent positive MRD before HSCT, while non-persistent uMRD was characterized by the presence of detectable MRD at least once before HSCT. The variables used for propensity score matching included induction chemotherapy cycles, consolidation chemotherapy cycles, and measurable residual disease (MRD) measurement by flow cytometer before HSCT. A caliper width of 0.2 was used. Following the matching process, 126 patients were selected for further analysis, with 42 patients in each of the auto-HSCT, MSD-HSCT, and AD-HSCT groups. Results After applying propensity score matching, a final cohort of 126 patients was available for analysis. This cohort consisted of 42 patients in each group: auto-HSCT, MSD-HSCT, and AD-HSCT. Among the AD-HSCT group, 38 of 42 (90.5%) patients received haploidentical HSCT (haplo-HSCT). All patients received myeloablative conditioning regimen. There were no significant differences observed in the 3-year overall survival (OS) and disease-free survival (DFS) among the auto-HSCT, MSD-HSCT, and AD-HSCT groups [3-year OS: 79.5% (95% CI, 67.8-93.3%), 83.0% (95% CI, 72.2-95.3%), and 65.7% (95% CI, 50.5-85.5%), respectively; P=0.21. 3-year DFS: 72.6% (95% CI, 59.9-87.9%), 83.0% (95% CI, 72.2-95.3%), and 67.5% (95% CI, 54.2-84.1%), respectively; P=0.32]. The cumulative incidence of 3-year NRM was 2.7% (95% CI, 2.0-12.5%), 7.3% (95% CI, 1.8-17.9%), and 21.9% (95% CI, 10.7-35.6%), respectively (P=0.008). The 1-year probability of OS after relapse was higher in the auto-HSCT group (44.4%; 95% CI, 21.4-92.3%) compared with MSD-HSCT (0.0%) and AD-HSCT (37.5%; 95% CI, 8.4-99.9%) (P=0.0017). The MRD status before HSCT had an impact on DFS (persistent uMRD versus non-persistent uMRD: HR=0.29; 95% CI 0.09-0.94, P=0.04) and relapse (persistent uMRD versus non-persistent uMRD: HR=0.17; 95% CI 0.05-0.66, P=0.01) following auto-HSCT. The subgroup analysis was then performed based on MRD status before HSCT. In patients with uMRD before transplant (n=83), OS was similar across the groups. However, auto-HSCT showed a trend of increased DFS compared to AD-HSCT (HR 2.85, P=0.09), resulting in a 3-year DFS and OS of 79.1% and 82.8%, respectively. In the non-persistent uMRD group (n=38), auto-HSCT exhibited a tendency to increase the risk of relapse, particularly when compared to AD-HSCT (HR 0.24, P=0.07), but this did not result in inferior OS. The monthly direct medical cost per patient within the first two years after HSCT was significantly lower in auto-HSCT compared to MSD-HSCT (P=0.015) and AD-HSCT (P<0.001). Conclusions Our results provide evidence for the use of auto-HSCT as a viable therapeutic option for favorable- and intermediate-risk de novo AML patients in first complete remission with persistent uMRD. Additionally, our findings demonstrated a notable cost advantage associated with auto-HSCT compared to MSD-HSCT and AD-HSCT.

CEBPA-Driven Expression of the Transcriptionally Inactive deltaTP73 Isoform Phenocopies TP53mutated Poor Risk and Drug-Resistant Acute Myeloid Leukemia

Mutations in TP53 ( TP53mut) are present in roughly 10% of acute myeloid leukemia (AML) patients and represent a unique subgroup of patients with very poor prognosis. While the exact mechanisms of TP53mut-driven leukemogenesis remain elusive, transcriptional changes associated with suppression of the TP53 signaling pathway are considered to confer a dismal prognosis on TP53mut patients. Using molecular profiling of a large cohort of AML patients (n=823) we identify a new poor prognostic subgroup in AML that is TP53 WT but shares strong similarities with TP53mut patients. Patients included in this new group present increased expression of the oncogenic TP73 gene isoform ΔNp73,which lacks the transactivation domain but still binds to chromatin. We find that the transcriptional and metabolic program of ΔNp73 high AMLs strongly resembles that of TP53mut AML, being enriched for stemness signatures like “17LSC” and “LSC UP”. In line with TP53mut AML, ΔNp73 high/ TP53 WT frequently co-occurs with U2AF1, SRSF2, TET2, and RUNX1 mutations . Lentiviral overexpression (OE) of ΔNp73 in healthy CD34 + cells increased cell proliferation and stemness. ΔNp73-OE in TP53 WT AML models, imposed drug resistance against several standard-of-care cytotoxic therapies in AML (e.g., AraC, venetoclax (VEN) ± azacytidine (AZA), and FLT3 inhibitors), while drug resistance was not further enhanced upon ΔNp73-OE in TP53mut AML models. These results were validated using ex vivo treated primary AML samples (n=80), whereby ΔNp73 high samples were more resistant to several cytotoxic therapies, including VEN+AZA . Lentiviral ΔNp73-OE in primary APL samples (n=10) allowed efficient engraftment in vivo using xenograft mouse models with colonization of secondary organs and splenomegaly, which was not observed in the empty vector controls. To unravel mechanisms via which ΔNp73controls oncogenic transformation we performed RNA-seq and ChIP-seq to identify direct transcriptional targets of TP53, ΔNp73, and the transcriptionally active isoform TAp73. These studies revealed that ΔNp73 and TP53 compete for the same target genes, whereby ΔNp73-OE resulted in complete loss of TP53 binding and strong downregulation of these loci, including downregulation of known TP53 target genes CDKN1A, BBC3, and GAS6, but also of TP53 itself. Gene set enrichment analyses of molecular programs in ΔNp73-OE cells revealed that these were associated with the terms “LSC UP”, “CEBPA targets”, and “SIGNAL TRANSDUCTION BY TP53”, indicating that ΔNp73 phenocopies TP53mut AML. Chromatin accessibility data on AML patients revealed a differentially accessible region in intron 2 (+24 Kb after the transcription start site, referred to as peak B) of the TP73 gene, with unknown regulatory functions on TP73 expression in AML. To access the potential enhancer functions of this region driving ΔNp73 expression we generated CRISPR/Cas9-KO MOLM13 cells lacking the peak B region (MOLM13-KO). MOLM13-KO cells exhibited reduced ΔNp73 expression, and the ability to up-regulate ΔNp73 expression upon high dose AraC-induced stress was abrogated. Since CEBPA was a transcription factor predicted to bind to Peak B, we investigated whether CEBPA could regulate the expression of the different TP73 isoforms. CEBPA-KD in AML cells resulted in decreased ΔNp73 levels and restored the TAp73 expression, suggesting that CEBPA controls the balance of the distinct TP73 isoforms. Pharmacological inhibition of CEBPA using the FDA-approved drug Guanfacine (GFC), diminished ΔNp73 levels and restored drug sensitivity against several cytotoxic agents in ΔNp73-OE AML cells. Moreover, the combination of GFC+VEN displayed strong synergistic effects in a cohort of ex vivo treated AML blasts (n=20), including patients with TP53mut, which are often resistant to VEN. Here, we describe a new AML patient subgroup that is TP53 WT but behaves similarly to TP53mut AML due to the expression of the ΔNp73 isoform that impairs TP53 signaling. This patient subgroup displays a very poor prognosis and is resistant to standard-of-care drugs used for AML patients. We identify a novel enhancer region that drives the expression of oncogenic TP73 isoforms, which is controlled by CEBPA, and inhibition of CEBPA by GFC enhances sensitivity to cytotoxic therapies in TP53mut-like AMLs. Our insightsfurther refine patient stratification and provide alternatives for treatment for the most dismal group of AML patients.

Low-Dose Decitabine Plus Venetoclax As Post-Transplant Maintenance for High-Risk Myeloid Malignancies

Background: Allogeneic stem cell transplantation (allo-SCT) is potentially curative for patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). However, post-SCT relapse remains a major cause of treatment failure for these patients and strategies to prevent post-transplant relapse are urgently needed. The combination of venetoclax (VEN) with either azacitidine (AZA) or decitabine (DEC) has shown promising results in older or unfit patients with AML and is now being investigated in younger patients as well. Herein, we report our experience of administering low-dose DEC and VEN as post-transplant maintenance in patients with high-risk myeloid malignancies. Methods: A retrospective chart review was performed to evaluate outcomes of patients with AML and MDS that received post-SCT maintenance with DEC and VEN at the University of Alabama at Birmingham. DEC was administered at 10mg/m 2 on days 1-3 per cycle and VEN was given at a target dose of 200mg on days 1-28 for AML and days 1-14 for MDS. The dose of VEN was reduced to 20mg when administered with voriconazole or posaconazole or 100mg when administered with fluconazole or isavuconazium. The cycle length was 4 weeks. Results: We identified 19 patients between March 2021 and May 2023 that received post-SCT DEC/VEN for AML and MDS (Table 1). The median follow-up was 10m (range 3-26m). The median age was 60y (range 34-69y). There were 10 (53%) females and 13 (68%) non-Hispanic whites (NHWs). Fourteen patients had AML and 5 had MDS. For patients with AML, 10 had poor-risk and 4 had intermediate-risk disease per ELN 2017. At the time of transplant, 11 patients with AML were in CR1 (CR1=6, CRi1=5), 2 were in CR2 (CR2=1, CRi2=1) and 1 was in CR3. Three patients with AML had MRD+ at the time of transplant (CRi1=2, CR3=1). For patients with MDS, 2 had very-high and 2 had high-risk disease per R-IPSS. One patient had therapy-related MDS. Two patients with MDS had CR, 2 had stable disease and 1 had hematological-improvement at the time of transplant. Overall, 6 patients (32%) had a TP53 mutation. Donor type was matched-related in 5 patients, matched-unrelated in 12 patients and haploidentical in 2 patients. Seventeen patients received reduced-intensity conditioning (RIC). GVHD prevention consisted of tacrolimus and methotrexate in 14 patients and post-transplant cyclophosphamide-based in 5 patients. The median time to initiating maintenance therapy was 69d (range 54-200d) post-SCT. The median number of cycles administered was 6 (range 2-24). Grade III-IV neutropenia, anemia and thrombocytopenia occurred in 5, 1 and 2 patients, respectively. Two patients had febrile neutropenia and one patient had candida esophagitis. Five patients required a reduction or interruption in the dose due to adverse events. In all cases, the VEN duration was shortened by 1 week. The cumulative incidence (CI) of day 100 grade II-IV and III-IV aGVHD was 13% and 5%, respectively. There were no grade IV cases. The 1y CI of moderate-severe cGVHD was 26%. To date, one patient who received a RIC haplo-SCT for poor-risk AML in CR2 relapsed 14m after SCT. The 1y non-relapse mortality was 11%. The 1y OS for the entire cohort was 84% (Figure 1). Conclusion: Our preliminary data suggests that the combination of low-dose DEC plus VEN is a safe and potentially effective strategy to reduce the risk of post-SCT relapse. Adverse effects mainly included manageable cytopenias with no increase in risk of GVHD. The efficacy of the combination appears to be promising but needs longer follow-up as well as confirmation in large, randomized studies.

Prognostic impact of complex and/or monosomal karyotypes in post-transplant poor cytogenetic acute myeloid leukaemia: Aquantitative approach.

To evaluate the prognostic impact of complex karyotype (CK) and/or monosomal karyotype (MK) in combination with various clinical factors on allogeneic stem cell transplantation (HSCT) outcomes of patients with acute myeloid leukaemia (AML), we analysed the registry database of adult AML patients who underwent allogeneic HSCT between 2000 and 2019 in Japan. Among 16 094 patients, those with poor cytogenetic risk (N = 3345) showed poor overall survival (OS) after HSCT (25.3% at 5 years). Multivariate analyses revealed that CK and/or MK (hazard ratio [HR], 1.31 for CK without MK; 1.27 for MK without CK; and 1.73 for both), age at HSCT ≥50 years (HR, 1.58), male sex (HR, 1.40), performance status ≥2 (HR, 1.89), HCT-CI score ≥3 (HR, 1.23), non-remission status at HSCT (HR, 2.49), and time from diagnosis to HSCT ≥3 months (HR, 1.24) independently reduced post-HSCT OS among patients with poor cytogenetic risk AML. A risk scoring system based on the multivariate analysis successfully stratified patients into five distinct groups for OS. This study confirms the negative effects of CK and MK on post-HSCT outcomes, and offers a powerful risk scoring system for predicting prognoses after HSCT among AML patients with unfavourable cytogenetics.

Targeted assembly of ectopic kinetochores to induce chromosome‐specific segmental aneuploidies

Cancer cells display persistent underlying chromosomal instability, with individual tumour types intriguingly exhibiting characteristic subsets of whole, and subchromosomal aneuploidies. Few methods to induce specific aneuploidies will exist, hampering investigation of functional consequences of recurrent aneuploidies, as well as the acute consequences of specific chromosome mis-segregation. We therefore investigated the possibility of sabotaging the mitotic segregation of specific chromosomes using nuclease-dead CRISPR-Cas9 (dCas9) as a cargo carrier to specific genomic loci. We recruited the kinetochore-nucleating domain of centromere protein CENP-T to assemble ectopic kinetochores either near the centromere of chromosome 9, or the telomere of chromosome 1. Ectopic kinetochore assembly led to increased chromosome instability and partial aneuploidy of the target chromosomes, providing the potential to induce specific chromosome mis-segregation events in a range of cell types. We also provide an analysis of putative endogenous repeats that could support ectopic kinetochore formation. Overall, our findings provide new insights into ectopic kinetochore biology and represent an important step towards investigating the role of specific aneuploidy and chromosome mis-segregation events in diseases associated with aneuploidy.

Clinical Experience of Allogeneic Hematopoietic Stem Cell Transplantation in Elderly Patients Aged 60 Years and Older in South Korea.

The purpose of this study is to share our outcomes and experiences on allogeneic hematopoietic stem cell transplantation (HSCT) in elderly patients aged 60 years and older with myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) in South Korea, and to compare them with other studies. We analyzed the clinical outcomes of 116 patients with AML or MDS aged 60 years and older who underwent allogeneic HSCT. We also analyzed which pretreatment factors affect the overall survival (OS) after allogeneic HSCT. Neutrophil and platelet engraftment were achieved at median day +11 [interquartile range (IQR) 10-15] and +14 (IQR 11-19), respectively. A complete donor chimerism was confirmed in 65 (56.0%) patients at 3 weeks and in 63 (54.3%) patients at 3 months after HSCT. The estimated incidence of grade II-IV acute graft-versus-host disease (GVHD) at day 100 was 13.7%. The estimated incidence of chronic GVHD at 2 years was 38.8%. Within a median follow-up of 14 months after HSCT, OS was 64% at 1 year and 55% at 2 years, and non-relapse mortality (NRM) was 20% at 1 year and 28% at 2 years. Multivariate analysis revealed that male sex and Hematopoietic Cell Transplantation-Specific Comorbidity Index ≥3 were associated with poor OS. This study showed that allogeneic HSCT in elderly adults aged 60 and older can be performed with successful engraftment and acceptable NRM and OS are expected given the generally known survival of patients with higher risk MDS and poor risk AML.

Prophylactic Donor Lymphocyte Infusion in Patients after Allogeneic Stem Cell Transplantation with Post-Transplant Cyclophosphamide Is Associated with Low Relapse Risk and Excellent Survival in Patients below 65 Years with Acute Myeloid Leukemia and High-Risk Myelodysplasia

BackgroundPost-transplant cyclophosphamide (PTCy) effectively prevents graft-versus-host-disease (GVHD) in allogeneic stem cell transplantation (alloSCT) with matched related and matched unrelated donors resulting in low risk of non-relapse mortality (NRM) (<10%). However, PTCy-alloSCT is associated with high relapse rates of approximately 20-30% after 1 year and 30-40% after 2 years (Gooptu et al. Blood 2021, Ruggeri et al. J Hemat Oncol 2018). Prophylactic donor lymphocyte infusion (DLI) may reduce relapse, although it may increase the risk of GVHD. AimTo provide evidence for reduction of relapse and improvement of survival by combining allogeneic SCT with PTCy and subsequent standardized prophylactic donor lymphocyte infusions (DLI) in a cohort of patients with acute myeloid leukemia (AML) and high risk myelodysplasia (MDS). Patients and MethodsSixty-five patients with AML (n=50) or high risk MDS (n=15) received myeloablative (n=15) or reduced-intensity (n=50) alloSCT with a matched related (n=8) or 9/10 (n=19) or 10/10 (n=38) matched unrelated donor. Based on modified ELN criteria, 10 AML patients were intermediate risk and 40 poor risk. GVHD prophylaxis consisted of PTCy, mycophenolate until day +30, and tacrolimus tapered from +70 (related or 10/10 unrelated) or day +90 (9/10 unrelated). All patients were planned to receive DLI at 6 months after transplantation at a dose of 3 x 10^6 CD3+ cells/kg in related and 1.5 x 10^6 CD3+ cells/kg in unrelated alloSCT. In poor risk patients (poor risk AML and high risk MDS) additional low dose DLI (0.3 or 0.15 x 10^6 CD3+ cells/kg in related and unrelated alloSCT, respectively) was planned one month after tacrolimus tapering (i.e. 3-4 months after alloSCT). In poor risk patients with a sensitive molecular or immunophenotypical minimal residual disease (MRD) marker (<0.1%) low dose DLI was not administered but MRD monitored; only in case of MRD positivity at 2 or 4 months additional low dose DLI was given. ResultsOf the 65 patients, 49 received standard dose DLI at 6 months after alloSCT (75%), either as a first dose at 6 months (40%), or as a second DLI after a low dose DLI at 3-4 months after alloSCT (35%). Reasons for not receiving standard dose DLI were NRM (5%), GVHD (9%), relapse (9%) and donor-related (2%). Of the 22 poor risk patients with a sensitive MRD marker, 15 received the first DLI at 6 months; 6 received both low dose DLI and 6 month DLI because of MRD positivity at 2 or 4 months after alloSCT; one patient did not receive prophylactic DLI because of systemic relapse at day 105. With a median follow up of 400 days (range 183-814), 12 patients developed systemic relapse. Most relapses (67%) occurred very early after transplant (median 110 days, range 63 to 165 days), before low dose DLI could be effectively given. These early relapses occurred significantly more in patients >= 65 years (88%) than <65 years (p=0.01 Fisher's exact). Overall survival at 1 year was 95% (95% CI 89-100%) in patients <65 (n=42), significantly higher than the 68% (95% CI 49-95%) in patients >=65 (n=23) (p=0.01). Relapse rate at 1 year was 5% (95% CI 1-15%) in patients <65, significantly lower than the 37% (95% CI 25-58%) in patients >=65 (p=0.001). Grade 2-4 acute and chronic GVHD incidence at 1 year was low (6% (95% CI 2-14%) and 11% (2.5-25%), respectively). Survival at 1 year was similar (p=0.35) in poor risk patients without MRD marker (80%, 95% CI 67-96%), poor risk with MRD marker (95%, 95% CI 87-100%) and intermediate risk (86%, 95% CI 63-100%). For these groups relapse risk was also similar: 18% (95% CI 7-33%), 16% (95% CI 3-36%) and 11% (95% CI 5-41%), respectively. ConclusionsThis study is the first to demonstrate feasibility of prophylactic DLI after PTCy-alloSCT with a low associated risk of GVHD. The observed low incidence of relapse at 1 year after transplantation (5%) of patients aged <65 years appears to be substantially less than the reported risk without pre-planned DLI (20-30%). Although the value of early DLI administration (around 3-4 months) is still unclear, standard dose DLI administration at 6 months appears feasible in intermediate risk patients and poor risk patients with sensitive MRD markers. Early relapses after alloSCT, at a time point before early DLI could be effective, caused the inferior survival of patients aged >= 65 years. The results of this study can serve as a reference for designing future prophylactic cellular interventions in the PTCy-alloSCT setting. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Specific Cytogenetic Abnormalities at Diagnosis Predict Survival after Hematopoietic Cell Transplant in Poor-Risk Pediatric Acute Myeloid Leukemia: A PDWP/EBMT Study

Introduction: Cytogenetic abnormalities are an important prognostic factor for predicting overall survival (OS) and relapse incidence (RI) in children with acute myeloid leukemia (AML). Although allogeneic hematopoietic cell transplant (HCT) is generally recommended for patients with AML in first complete remission (CR1) and poor-risk (PR) cytogenetics, whether these cytogenetic and molecular features retain their prognostic value after HCT is unknown. Additionally, PR AML is a heterogeneous category that includes several distinct cytogenetic abnormalities, some of which might have a worse prognosis than others. In this study, we evaluated whether the cytogenetic risk classification at diagnosis of AML was predictive of post-HCT outcomes in pediatric patients. Methods: All patients <18 years of age at the time of HCT reported to the European Society for Blood and Marrow Transplantation (EBMT) registry, who had received their first allogeneic HCT for AML in CR1 between 2005 and 2020, and who had their karyotype evaluation at diagnosis available were included in this analysis. Patients were subgrouped as (a) monosomy 7/del7q or monosomy 5/del5q, (b) 11q23 abnormality excluding t(9;11), (c) complex or monosomal karyotype, or (d) other. A complex karyotype was defined as one with three or more structural abnormalities, and a monosomal karyotype was defined as a monosomy with one or more structural abnormalities, excluding WHO-designated recurring translocations or inversions based on 2017 ELN recommendations. Other cytogenetic abnormality subgroup included t(6;9), t(3;5), t(9;22), t(8;16), inv(3) or t(3;3), t(16;21), abn(11p15), and del(12p) or abn(12p13). Cytogenetic subgroup, age at HCT, whether HCT was from a female donor to a male recipient, patient/donor CMV status, time from AML diagnosis to HCT, and year of HCT were included as predictors for OS, RI and non-relapse mortality (NRM) in the multivariate analysis. Results: We included 744 pediatric patients (42.2% female; median age at HCT: 8.6 years [range: 0.3-18 years]) from 139 participating centers in the study. Median follow-up after HCT was 4.4 years. Thirty-seven percent had an 11q23 abnormality, 24% had monosomy 7/del7q or monosomy 5/del5q, 24% had a complex or monosomal karyotype, and 15% met the criteria for other PR cytogenetic abnormalities. Only 7% had secondary AML. Pre-HCT minimal residual disease (MRD) data were available for 346 patients, 86% of whom were MRD negative at the time of HCT. Patients received grafts from a matched related donor (27%), a mismatched related donor (11%), an unrelated donor (46%), or a cord blood donor (16%). Of the total patients, 55% received bone marrow, 29% received peripheral blood-derived stem cells and the rest (16%) received cord blood as the stem cell source. Myeloablative conditioning was used in 97% of the patients. The OS and leukemia free survival for the entire cohort was 76% and 70% respectively at 2 years. In a multivariate model, 11q23 (hazard ratio [HR] = 0.59, P = 0.01) and other poor-risk cytogenetic abnormalities (HR = 0.49, P < 0.01) were associated with significantly better OS when compared with monosomy 7/del7q or monosomy 5/del5q. The "other PR cytogenetic abnormalities" category was also associated with a lower risk of disease relapse after HCT (HR = 0.4, P = 0.01). Receiving an HCT from an unrelated donor, as compared with a matched related donor, was associated with lower RI (HR = 0.58, P = 0.03). Additionally, older age at HCT (12-18 years) was associated with the highest risk of NRM (HR = 1.95, P = 0.02) and with worse OS (HR = 1.71, P < 0.01) than seen in younger patients (aged 4-12 years). Conclusion: PR cytogenetic abnormalities at diagnosis remain predictive of OS after HCT for AML in pediatric patients. Monosomy 7/del7q or monosomy 5/del5q confer a poor prognosis even after HCT, whereas 11q23 abnormality and other PR cytogenetic abnormalities predict a favorable outcome after HCT. Our data also suggest that an HCT from an unrelated donor may offer greater protection against relapse than an HCT from a matched related donor, but this requires further validation. Efforts for improving conditioning regimens and transplant techniques should focus on reducing NRM and reducing RI in this population. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Maintenance with Hypomethylating Agents Post-Transplant in Acute Myeloid Leukemia Patients: Safe and Affordable Way to Induce Graft Versus Leukemia Effect

INTRODUCTION Allogenic stem cell transplantation (ASCT) is the only optimistic therapy for poor risk, relapse and/or refractory acute myeloid leukemia (AML) patients for better survival outcome. However, 40% of the patients relapse after ASCT translating into 2-year survival rates below 20% and majority of relapses occurs within 12-18 months of transplant (Devillier, Leukemia & Lymphoma 2013). Hence, it's reasonable to start maintenance therapy as early as possible for such high risk AML. Azacytidine, an hypomethylating agent (HMA) has been shown previously as a potential maintenance drug to be used in post transplant setting (Oran, Blood advances 2020). Recently Keruakous (Hematology/Oncology and Stem Cell Therapy, 2021) had showed that the relapse rate was significantly higher in the control cohort (66.67%) versus in the azacytidine maintenance cohort (25.81%). On the similar concept, we analyzed our AML patients who received maintenance with HMA post transplant. OBJECTIVE To analyze the Relapse free survival (RFS) and overall survival( OS) in AML patients post-transplant with the use of HMA maintenance therapy. METHODS It's a retrospective analysis of AML patients who have undergone ASCT at our centre between May 2020 and April 2022. Maintenance was given to all patients post ASCT irrespective of MRD status post transplant and risk classification pre-transplant. Patients who received maintenance with HMA (either azacytidine@ at 32 mg/m2 daily for 5 days 4 weekly or decitabine @10mg/m2/day for 5 days 6 weekly) and had completed at-least one cycle were included (Oran, Blood advances 2020 and Pusic, Biol of Blood Marrow Transplant 2015). Maintenance was planned for minimum of one year. OS and RFS was calculated by the Kaplan-Meier curves. Events included relapses and deaths. RESULTS Twenty-six patients (AML=24, MDS=1, CMML=1) received maintenance with HMA during the study period. Mean age was 31.5 (14-51) years and 15 (57.69%) patients were male. As per European Leukemia Net (ELN) 2017 classification 5 (19.2%), 12 (46.1%) and 7 (26.9%) patients were categorized into favorable risk, intermediate risk and adverse risk respectively. There were 14 (53.8%) patients in Complete remission (CR1) group, 10 (38.4%) in CR2 group and two(7.6%) were refractory disease. Source of graft was peripheral blood stem cell for all patients. Conditioning regimen was myelo-ablative in 22 (84.6%) patients, whereas 4 (15.3%) patients received reduced intensity. Donors were matched sibling (n=15, 57.69%), haplo-identical (n=6, 23.07%), matched unrelated (n=4, 15.38%) and mismatched unrelated(n=1,3.8%). Azacytidine was started within 100 days of transplant in 22(84.61%) patients. The median of number of cycles of HMA received were 6. The median duration of follow up was 13 months. Seven (26.9%) patients completed 12 cycles. Acute Graft versus host disease (GVHD) was seen in 7 patients (26.9%) involving skin and liver whereas 3 (11.5%) patients had chronic GVHD involving skin and eye. Three (30%) patients developed GVHD prior and 7(70%) developed GVHD post initiation of maintenance. Six (85.7%) patients who relapsed on HMA maintenance had no prior acute or chronic GVHD. Out of all the 7(26.9%) patients who relapsed, 6 patients relapsed within a year and one patient relapsed after a year. One year RFS was 71% (Figure1), Event Free Survival was 67.9% and OS was 81.4% (Figure 2) Only 1 (3.8%) patient had Transplant Related Mortality (TRM), who died of COVID-19 infection. OS at 1 year for those in CR1 and CR2 was 84.6% and 88.9% respectively and it was not statistically significant (P = 0.95). There was no substantial hematological toxicity and resulting drug interruptions during the maintenance. CONCLUSION Early HMA maintenance seems to be an effective strategy post ASCT in AML patients to prevent early relapses and improving overall survival. Development of GVHD for patients on HMA had probably synergistic effect to prevent relapses by mediating graft versus leukemia effect without additional toxicity. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

TP53 Altered Acute Myeloid Leukemia Stem Cells Hyperactivate Nuclear Factor-Kappa B

In acute myeloid leukemia (AML), standard therapies induce complete remission in 50-70% of patients, but the overall two-year survival is less than 20-30% because of high relapse rates. AML with mutations or deletions in TP53 (TP53 altered, TP53Alt) is a poor-risk AML subtype that is largely insensitive to chemotherapy, modern targeted agents, and hematopoietic stem cell transplantation. TP53Alts are seen in approximately 10-20% of AML and confer a particularly poor prognosis decreasing the 1-2-year survival rates to 0-10%. Leukemia stem cells (LSCs), the cells that recapitulate and propagate leukemia, are central drivers of leukemia progression and relapse. Therapeutically targeting LSCs is important to curing AML, but LSCs are poorly proliferative in contrast to bulk AML cells and are less sensitive to standard chemotherapy. Despite a broad literature defining the immunophenotype (the cell surface marker expression profile) and mechanisms of self-renewal of LSCs, the TP53 status has not been reported in most studies of human LSCs. Our goal is to define the immunophenotype and molecular states of primary human TP53Alt LSCs. First, we asked whether the LSC immunophenotype of TP53Alt AML is consistent with that of the previously reported LSC immunophenotype in AML. We sorted primary human TP53Alt AML samples and plated cells from sorted compartments in serial colony forming assays (which serve as an in vitro surrogate for self-renewal). We found that the Lineage-CD34+CD38-compartment is enriched in serial colony forming capacity in four primary human TP53Alt samples tested. In another TP53Alt sample, we found that the Lineage-CD34+CD38any compartment was enriched for serial colony formation. In vivo engraftment studies recapitulated these findings in one of the TP53Alt AML sample we tested. In the two CD34-TP53Alt AML samples studied the lineage-CD123+ compartment was enriched in serial colony forming capacity. Together, these findings suggest that the standard AML LSC markers also identifies the LSC compartment of TP53Alt AML. Next, we used mass cytometry (CyTOF) to define the proliferative and signaling states of human TP53Alt AML samples. Previous work has demonstrated that the LSC compartment of AML is poorly proliferative, relative to the bulk leukemia population. Consistent with these findings, we found low levels of Ki67 (a proliferation marker) expression, in TP53Alt LSCs, relative to bulk leukemia cells, in every primary TP53Alt AML that we profiled (n=7). Notably, we found that TP53Alt LSCs express high levels of pNFkB, p4EBP1, and pSTAT5, suggesting that these signals may mediate self-renewal in TP53Alt AML. Indeed, we found that CD69, an NFkB target gene, is elevated in TP53Alt LSCs and minimally expressed in bulk leukemia cells. Furthermore, we found that Ki67 levels are low in the CD69High subset, suggesting that this is a poorly proliferative subset (consistent with having self-renewal capacity). Finally, we sorted primary samples according to CD69 status and found that CD69marks a subset with enhanced serial colony forming capacity. Together, these findings demonstrate that traditional LSC markers can be used to study TP53Alt LSCs and that NFkB activation is correlated with self-renewal function in these LSCs. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

CPX-351 Induction in Secondary Acute Myeloblastic Leukemia: Extended Follow up from the Italian Compassionate Use Program

Introduction:The outcome of patients with acute myeloid leukemia (AML) secondary to myelodisplastic syndrome (MDS) or therapy-related (t-AML) receiving conventional treatment and allogeneic stem cell transplantation consolidation (HSCT) is poor. CPX-351 is a new drug composed by liposomal encapsulated cytarabine and daunorubicin, at a fixed molecular ratio of 5:1. It showed superior results, compared to standard 3+7 induction, in a phase III trial (Lancet et al, JCO 2018) in patients affected by t-AML or AML with myelodisplasia-related changes and it is now commercially available for secondary AML (sAML). We recently published results from CPX-351 Italian Named (Compassionate) Use Program (CUP) which enrolled 73 elderly sAML patients (Guolo et al, Blood Cancer J. 2020) showing that CPX-351 is an effective induction regimen for high risk AML patients treated with a curative aim. With a limited follow up, our data suggested the good activity and tolerability of CPX-351. Good quality remissions with acceptable toxicity in the majority of patients was achieved and CPX-351 increased the feasibility of HSCT in a poor risk AML cohort. Scarce data are available on long term outcome of high risk patients receiving CPX-351 in the real life setting. Here we report the results from the extended follow up analysis of the Italian CUP.Results:Seventy three patients were enrolled between December 2018 and June 2019 in a compassionate use program (CUP) in 33 Italian Hematology Centers. Data collection began on July 2019 and included 71/73 patients (97.2%), enrolled in 31 Centers.As previously reported, median age was 65.5 years (52-79). Sixty-two (88%) patients had at least one relevant comorbidity upon enrollment. Six patients (9%) presented with ECOG 3-4 upon enrollment.With a median follow up of 22 months, median overall survival (OS) was 13 months (21.2 - 22.8 95% IC). Two-years OS was 28.6% in the whole cohort. In order to confirm the positive impact of HSCT in first complete remission (CR) and the correlation with the other variables, a landmark model was applied, including only patients alive and in CR at day 90. In landmark analysis, HSCT performed in first CR after CPX-351 was the only significant predictor of longer survival: median OS was not reached for patients transplanted in first CR Vs 12 months for patients who did not undergo HSCT, p < 0.05, Figure1). Two-year OS for patients who received HSCT was 57.6% vs 15.8% for patients who did not undergo HSCT.Conclusions:Results from the extended follow up of Italian CPX-351 CUP confirm the good activity CPX-351 in such a difficult cohort as sAML. Two-year OS for transplanted patients is high despite the high median age, the high frequency of severe comorbidities in this real life cohort of patients and the high frequency of high risk AML. On the contrary, non-transplanted patients show a poor outcome, thus confirming that CPX-351 induction as an optimal bridge to transplant induction therapy. [Display omitted] DisclosuresGalimberti: Incyte: Speakers Bureau; AbbVie, Janssen: Honoraria, Other: Travel grants. Marco: Insight,: Consultancy; Jazz: Consultancy; Janssen: Consultancy. Fracchiolla: Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria, Speakers Bureau. Tafuri: Roche: Research Funding; Novartis: Research Funding; Celgene: Research Funding. Rossi: Novartis: Membership on an entity's Board of Directors or advisory committees; Jazz: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Consultancy, Honoraria; Celgene: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Alexion: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria; Takeda: Membership on an entity's Board of Directors or advisory committees. Pagano: Gilead Science, MSD, Pfizer, Basilea, Janssen, Novartis, Jazz Pharmaceutical, Cidara: Membership on an entity's Board of Directors or advisory committees; Menarini: Consultancy; Gilead Sciences, MSD, Pfizer Pharmaceuticals, Astellas Pharma: Speakers Bureau.

Detecting and preventing post-hematopoietic cell transplant relapse in AML.

Relapsed disease is the primary cause of mortality for acute myeloid leukemia (AML) patients after allogeneic hematopoietic cell transplantation (HCT). This review outlines the most recent advances in the detection and prevention of AML relapse following allogeneic HCT. Conventional methods for predicting post-HCT relapse rely on the molecular and cytogenetics features present at diagnosis. These methods are slow to reflect a growing understanding of the molecular heterogeneity of AML and impact of new therapies on post-HCT outcomes. The use of measurable residual disease (MRD) techniques, including multiparameter flow cytometry and molecular testing, may improve the prognostic ability of these models and should be incorporated into post-HCT surveillance whenever possible.In the post-HCT setting, FLT3 inhibitor maintenance data indicate that effective therapies can improve post-HCT outcomes. Maintenance data with DNA methyltransferase inhibitor monotherapy is less compelling and outcomes may improve with combinations. Early interventions directed at preemptive management of MRD may further improve post-HCT outcomes. Post-HCT AML relapse prevention has evolved to include more sensitive measures of disease detection and novel therapies that may improve outcomes of poor-risk AML patients. Additional work is needed to maintain this progress.

3+7 Combined Chemotherapy for Acute Myeloid Leukemia: Is It Time to Say Goodbye?

With the recent approval of multiple new drugs for the treatment of acute myeloid leukemia (AML), the relevance of conventional treatment approaches, such as daunorubicin and cytarabine ("3+7") induction chemotherapy, has been challenged. We review the AML risk stratification, the efficacy of the newly approved drugs, and the role of "3+7". Treatment of AML is becoming more niched with specific subtypes more appropriately treated with gemtuzumab, midostaurin, and CPX-351. Although lower intensity therapies can yield high response rates, they are less efficient at preventing relapses. The only curative potential for poor-risk AML is still an allogeneic stem cell transplant. The number of AML subtypes where 3+7 alone is an appropriate therapeutic option is shrinking. However, it remains the backbone for combination therapy with newer agents in patients suitable for intensive chemotherapy.

Erratum

Hematological OncologyVolume 39, Issue 3 p. 434-434 ERRATUMFree Access Erratum First published: 11 August 2021 https://doi.org/10.1002/hon.2911AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat In [1], the eighth author name was misspelt. The correct name is Amjad Hayat. We apologize for this error. Reference 1Krawczyk J, Ansar N, Swords R, et al. Clofarabine in the treatment of poor risk acute myeloid leukaemia. Hematol. Oncol. 2010; 118– 123. https://doi.org/10.1002/hon.922PubMedWeb of Science®Google Scholar Volume39, Issue3August 2021Pages 434-434 ReferencesRelatedInformation

A phase II study of azacitidine in combination with granulocyte-macrophage colony-stimulating factor as maintenance treatment, after allogeneic blood or marrow transplantation in patients with poor-risk acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS)

Relapse is the most common cause of treatment failure following allogeneic blood or marrow transplantation (alloBMT) for AML or MDS. Post-transplant maintenance therapies may prevent relapse. We conducted a phase II trial combining azacitidine (AZA) with GM-CSF in non-relapsed, post-transplant patients with AML or MDS. Patients received escalating doses of AZA to a maximum of 75 mg/m2 for 5 days per cycle for up to 12 cycles. GM-CSF was given on days 1–10 of each cycle. Eighteen patients were treated following non-myeloablative (17) and myeloablative (1) alloBMT for AML (61.1%), MDS (27.7%), or therapy-related myeloid neoplasm (11.1%). The majority of patients (72%) received their graft from an HLA-haploidentical donor. The treatment was well-tolerated with rare grade 3–4 hematologic toxicities. One patient suffered an exacerbation of GVHD. The 24-month relapse-free and overall survivals were 47 and 57%, respectively, with a median of 18.6 and 29 months.

Favorable Outcomes with Fludarabine, High Dose Cytarabine and Granulocyte Colony Stimulating Factor (FLAG) As Re-Induction for Residual Acute Myeloid Leukemia on Day 14 Bone Marrow

BACKGROUND:Initial response to standard induction therapy for acute myeloid leukemia (AML) is typically assessed by a bone marrow biopsy on day 14 (D14). However, there does not appear to be a consensus on who should receive re-induction therapy and what regimen to choose if treatment is given. Fludarabine, high dose cytarabine and granulocyte colony stimulating factor (FLAG) regimen has been used at our institution for re-induction in patients with residual disease on D14 marrow evaluation.METHODS:A retrospective chart review was performed to evaluate adult patients with AML who received re-induction with FLAG for residual leukemia on D14 marrow between September 2012 and July 2017 at our institution. All patients included in the analysis received standard induction chemotherapy with cytarabine and an anthracycline. Approval for the study was obtained from the IRB.RESULTS:We identified 27 patients that received FLAG as re-induction (Table 1). The median age at diagnosis was 61 years (range 19-77). Median WBC count at presentation was 5.8 X10^3/ml (range 0.6-132) and bone marrow blast % was 64 (range 30-95). Most patients (63%) had poor risk disease based on cytogenetics and molecular abnormalities (as per NCCN AML guidelines), one patient (4%) had favorable risk disease with the rest of the patients (33%) having intermediate risk disease. The D14 marrow had a minimum cellularity of more than 20% in 14 patients. The median blast % by morphology on the D14 marrow was 60% (range 9-95). The overall response rate (CR/CRp/CRi) was 78% with 17 out of 27 (63%) patients achieving complete remission (CR). Four patients (15%) had resistant disease after FLAG based on a bone marrow evaluation and 2 patients died of indeterminate cause. Of the 4 patients with resistant disease, 1 achieved CR with a second cycle of FLAG. Overall, three patients died in the hospital during re-induction.The median time period for neutrophil count recovery (ANC >500) from re-induction date was 19 days (range 15-33). The median length of hospital stay after re-induction for patients that were discharged was 22.5 days (range 17-41). Fifteen patients (56%) proceeded to hematopoietic stem cell transplant (HSCT). Out of the 15, 14 were in CR1 at the time of HSCT. At the last follow up, 16 patients were in remission. The median follow up time period after re-induction was 224 days (range 11-1,663). The median time to relapse for patients that achieved CR after initiating FLAG re-induction was 233 days (range 152-676). The 1 and 2 year overall survival (OS) rates were 72% and 62% respectively (Figure 1).CONCLUSION:We report favorable outcomes with FLAG as a re- induction regimen for patients found to have residual AML on D14 bone marrow biopsy following standard induction chemotherapy. The median age of our population was > 60 years and 63% of the patients had poor risk AML. Within the limitations of a small retrospective study, FLAG was well tolerated with 3 patients expiring during the initial hospitalization. For AML patients with residual disease 14 days after standard induction therapy and who are able to receive further treatment, FLAG is a reasonable salvage option. [Display omitted] DisclosuresErba:Celgene: Consultancy, Other: Chair, Scientific Steering Committee , Speakers Bureau; Incyte: all research support paid to University of Alabama, Consultancy, Speakers Bureau; Jazz: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Amgen: Consultancy, Other: all research support paid to University of Alabama, Research Funding; Daiichi Sankyo: Consultancy, Other: all research support paid to University of Alabama, Research Funding; ImmunoGen: Consultancy, Other: all research support paid to University of Alabama, Research Funding; MacroGen: Consultancy; Ono: Consultancy; Pfizer: Consultancy; Seattle Genetics: Consultancy, Other: all research support paid to University of Alabama, Research Funding; Sunesis: Consultancy; Millennium/Takeda: Consultancy, Other: all research support paid to University of Alabama, Research Funding; Agios: Other: all research support paid to University of Alabama, Research Funding; Juno: Other: all research support paid to University of Alabama, Research Funding; Astellas: Other: all research support paid to University of Alabama, Research Funding; Celator: Other: all research support paid to University of Alabama, Research Funding; Janssen: Other: all research support paid to University of Alabama, Research Funding; Glycomimetics: Other: Chair, Data and Safety Monitoring Committee.

The CXCL12/CXCR4 Pathway As a Potential Target of Tipifarnib in Acute Myeloid Leukemia and Myelodysplastic Syndromes

BackgroundCXCL12 is a chemokine that is essential for homing of myeloid cells in the bone marrow (BM). It has been postulated that a CXCL12 receptor present in myeloid cells, CXCR4, signals in part through HRAS, a protein that is uniquely dependent on farnesylation for activity. Tipifarnib is a potent and selective inhibitor of the enzyme farnesyltransferase (FT) that had been shown to provide clinical benefit in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS); however, no molecular target that could explain the activity of tipifarnib in AML and MDS has been identified. Based on initial observations in T cell lymphoma (Witzig EHA 2017), we investigated a role for CXCL12 and myeloid cell homing in BM as biomarkers of the activity of tipifarnib in AML and MDS studies.MethodsCTEP20 was a phase 2, multicenter, open-label study that investigated the efficacy and safety of tipifarnib in 158 older adults with previously untreated, poor-risk AML. AML301 was a phase 3 (N=457), multicenter, open-label study that evaluated the efficacy and safety of tipifarnib compared with best supportive care (BSC), including hydroxyurea, as first-line therapy in elderly patients with newly diagnosed, de novo, or secondary AML. INT28 was a multicenter phase 2 study that evaluated tipifarnib in 82 pts with poor-risk MDS. Global gene expression data generated using the Affymetrix U133A gene chip from 34 pretreatment BM samples collected from CTEP20 pts (GSE8970) was analyzed with respect to pretreatment hematological parameters and study outcomes. The Kaplan-Meier method was employed to estimate survival and progression free survival (PFS) and the analysis of prognostic variables. Clinical trial information: NCT00027872, NCT00093990, NCT00050154.ResultsNine complete responses (CR) and 13 best responses of progression of disease (PD) were observed in 34 pts with available BM gene expression data in study CTEP20. Pts in the 3rd (upper) tertile of CXCL12 expression experienced 6 CRs and 2 PDs whereas 1 CR and 8 PDs were observed in the 1st (lower) tertile (p=0.015). BM homing of AML blasts correlated with CXCL12 expression: Median percentage of BM blasts (BMB) and peripheral blasts (PB) were, respectively, 45% and 0% in the upper CXCL12 tertile, and 30% and 26.5% in the lower tertile (p<0.001) (Figure, A). Pts with high tumor burden in BM (BMB blasts>40%) and low circulating blasts (PB<1%) (N=5) had high CXCL12 expression in BM (3423 vs 742 counts, P<0.001, N=27) and experienced prolonged clinical benefit, with 5 CRs and a median PFS of 431 days (431 vs 35 days, HR=0.23, P<0.001, N=27) (Figure, B). The effect of BM homing was then investigated in the phase 3 AML301 trial of tipifarnib vs BSC. While the overall study (N=457) failed to identify an increased efficacy of tipifarnib compared with BSC (median survival of 109 vs 107 days, hazards ratio, HR=1.02, ns), median survival approximately doubled in the tipifarnib am compared with BSC in the subset of patients with high BMB (>40%) and low PB (<10%) while no effect was observed in the control arm (201 vs 109 days, HR=0.58, p=0.02, N=82) (Figure, B). Since CXCL12 is also a potent chemotactic factor for normal neutrophils and syndromes of hyperactivation of the CXCL12/CXCR4 pathway present with neutropenia, we investigated whether neutropenia could be a surrogate of tipifarnib activity. In AML301 pts with WBC counts>LLN (no myelosuppression), increasing neutropenia correlated with increasing clinical benefit from tipifarnib that was due in part to a poorer prognosis of BSC in neutropenic pts (113 vs 80 days median OS, HR=0.81, p=0.036, N=109, for pts with baseline neutrophils<1 giga/L). Finally, we tested the effect of neutropenia on the activity of tipifarnib in INT28. Sixty seven of the 82 MDS pts were transfusion dependent (TD) at study entry. Overall conversion to transfusion independence (TI) and response rate (ORR: CR, CRp, PR) were respectively 16% and 7.5% in the TD pts. Pts with >1 giga/L neutrophils at study entry experienced 5% TI and no responses (N=37) while 30% TI, 2 CRs, 2 CRp and 1 PR were observed in the subset of neutropenic pts.ConclusionCXCL12 expression and BM homing constitute potential biomarkers of the activity of tipifarnib in AML and MDS supporting the hypothesis that the CXCL12 pathway is a potential target of FT inhibitors. [Display omitted] DisclosuresGualberto:Kura Oncology: Employment, Equity Ownership, Other: Chief Medical Officer, Patents & Royalties. Scholz:Kura Oncology: Employment, Equity Ownership, Patents & Royalties. Janes:Wellspring Biosciences: Employment. Kessler:Kura Oncology: Employment. Raza:Kura Oncology: Research Funding; Syros Pharmaceuticals: Research Funding; Novartis: Speakers Bureau; Celgene Inc.: Research Funding; Genoptix: Speakers Bureau; Onconova Therapeutics: Research Funding, Speakers Bureau; Janssen R&D: Research Funding.

Clinical Outcomes of Microtransplantation for Older Adults with Acute Myeloid Leukemia

Introduction: Outcomes of acute myeloid leukemia (AML) in older patients remain unsatisfactory with low rates of complete remission (CR), disease-free survival (DFS), and overall survival (OS). Microtransplantation - in which allogeneic cells are infused without substantial engraftment (<2% donor cell engraftment) - has the potential to improve anti-tumor immunity without the risks of allogeneic hematopoietic stem cell transplant and graft-vs-host disease (GVHD).Methods: Adapting the protocol of Ai et al. (Blood 2011;117(3):936-41), newly diagnosed high-risk AML patients ≥ 55 years received induction with cytarabine100 mg/m2, idarubicin 12 mg/m2, and microtransplantation (7+3+MST). Microtransplantation was given 24-48 hours after 7+3 and consisted of a G-CSF mobilized leukapheresis product from a HLA-haploidentical family donor; a minimum of 1x108 CD3+ cells/kg were infused. Subjects in CR received 2 cycles of consolidation with high dose cytarabine (HiDAC); the second cycle was followed by another MST. Subjects not in CR were allowed to undergo a 2nd repeat induction cycle (7+3+MST).Results:We enrolled seventeen patients (Table 1) with a median of 248 days of follow up (range 37-887). The median age was 73 years (range 61-78); 5 (29%) had an antecedent hematologic disorder, and 10 (59%) had adverse-risk cytogenetics. Overall, 12 (71%) had poor-risk AML defined as either therapy-related AML, antecedent hematologic disorder, or adverse-risk cytogenetics; 2 (12%) had intermediate-risk AML, and 3 (18%) had favorable-risk AML (all three NPM1 positive).One patient developed sepsis during induction and did not receive microtransplantation; of the other sixteen patients that received at least one round of 7+3+MST, 10 (62.5%) achieved a complete remission, including 4 of 4 patients with intermediate or favorable risk AML (100%) and 6 of 12 with poor-risk AML (50%). Of the 10 in CR, 9 achieved CR after one round of induction and one required a second induction. Nine completed consolidation while one stopped after the first cycle of consolidation due to deconditioning. Three (19%) remain disease-free and alive at 100, 274, and 737 days. Interestingly, all three of these patients had fevers/chills during or immediately after MST. There were no further complications with MST, no cases of treatment-related mortality, and no cases of GVHD, consistent with absence of substantial engraftment. Estimated survival at six months was 67% and at one year was 34% (Figure 1). Correlative studies of immunomodulatory effects, including T-cell exhaustion and NK cell function, depth of response (minimal residual disease), and persistence of donor cells (microchimerism) are pending to better understand the potential mechanisms by which microtransplantation may improve disease responses.Conclusion: Microtransplantation is a potentially safe and effective therapy for older patients with AML. High rates of complete remission were observed in both those with favorable/intermediate risk disease as well as those with poor-risk disease. Further studies are warranted into the efficacy and mechanisms of microtransplantation. [Display omitted] DisclosuresSung:Novartis: Research Funding; Merck: Research Funding; Cellective: Research Funding. LeBlanc:Seattle Genetics: Research Funding; Helsinn Therapeutics: Consultancy, Honoraria; Boehringer Ingelheim: Membership on an entity's Board of Directors or advisory committees; Otsuka: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria; Pfizer: Consultancy; AstraZeneca: Research Funding; American Cancer Society: Research Funding; Celgene: Honoraria; Cambia Health Foundation: Research Funding; Flatiron Health: Consultancy. Brander:Teva Pharmaceuticals, Genentech, AbbVie, Pharmacyclics: Consultancy; TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Genentech: Consultancy; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees. McKinney:Kite Pharma: Other: advisory comittee. Sipkins:Gilead Sciences, Inc.: Research Funding. Rizzieri:Shire: Research Funding; Erytech: Research Funding.