European LeukemiaNet Research Articles

Validation of ELN 2022 Risk Classification in Patients Diagnosed with AML Undergoing Allogeneic Hematopoietic Cell Transplantation

Background: In 2022, the European LeukemiaNet (ELN) updated their guidelines (Döhner H et al., Blood 2022) for risk allocation of patients with acute myeloid leukemia (AML) based on essential genetic features at diagnosis as defined in the newest classifications (Arber D et al., Blood 2022, Khoury JD et al., Leukemia 2022). Methods: Retrospective analysis of the 147 consecutive patients diagnosed with AML and available genetic information who underwent alloHCT in a complete morphological response (CR) between 2011 and 2021 in a single institution (HCB). Data was collected retrospectively and updated in July 2023. G-banding karyotype, FISH, qualitative and quantitative PCR and targeted Next Generation Sequencing were assessed at diagnosis to classify patients according to ELN 2022 risk classification. Our primary goal was to validate the ELN 2022 risk classification in patients undergoing alloHCT analyzing overall survival (OS). Secondary objectives were analyzing leukemia-free survival (LFS), 24-month cumulative incidence of relapse (CIR) and in the different molecular subgroups within the ELN2022 risk groups. Results: The main patient, disease-related and transplant characteristics are displayed in Figure 1. Overall, the median age was 52 years (range 18-70), 53.7% of the patients males, with 88% of the patients undergoing alloHCT in CR1. Twenty-two patients could not be classified through NGS assessment between 2011 and 2016 and included in the intermediate risk category due to normal karyotype and wildtype recurrent abnormalities measured by PCR. Patients in the adverse-risk group were older (p <0.001) and underwent alloHCT less often with undetectable measurable residual disease (p = 0.006). Moreover, patients in the favorable or intermediate risk group underwent alloHCT more often in CR2 or CR3 (p = 0.02). In addition, alloHCT characteristics were similar for all the patients included. With a 67-month median follow-up for LFS (95CI: 55-76), the median OS and LFS in patients classified into the favorable and intermediate risk groups were not reached (5-year OS and LFS rate in favorable risk group: 81% (95CI: 73-89) and 72% (95CI: 63-81). 5-year OS and LFS rate in intermediate risk group: 62% (95CI: 56-68) and 64% (95CI: 58-70). Patients included in the adverse risk group had an OS and LFS of 23.7 months (15.3-NR, p <0.001 between intermediate and adverse risk. Figure 1B) and 15.2 months (5.79-NR, p=0.015) respectively, with a significant lower 5-year OS rate (40%, 95CI: 34-46), LFS rate (38%, 95CI: 32-44) and a higher CIR (18% in the favorable risk group (95%CI: 11-26) vs. 20% in the intermediate risk group (95%CI: 18-23) vs. 40% in the adverse risk group (95%CI: 38-44), p = 0.024). Based on these results, a subanalysis was conducted in the patients classified into the adverse group. Those patients diagnosed with complex karyotype, inv(3), t(3;3), del(17p) and/or TP53 mutated were reassessed into a new risk category group called: Adverse-Plus (AdvP).No different baseline characteristics between the AdvP patients and the other subgroups were found. AdvP patients presented a shorter OS (NR in the rest of subgroups vs. 8.73 months in AdvP, p < 0.001 for AdvP vs. adverse risk. Figure 1C), LFS (NR in the rest of subgroups vs. 5.2 months, p < 0.001), and a higher CIR (62.5% in the AdvP group, p <0.001 between adverse risk and AdvP). Interestingly, using this four-group classification including AdvP, the other risk groups presented similar OS, LFS, and CIR without statistical differences in between them Summary/Conclussion: ELN2022 risk classification discriminates properly accurate in patients undergoing alloHCT. Reclassifying AML adverse risk patients diagnosed with complex karyotype, inv(3), t(3;3), del(17p) and/or TP53 mutated in a different subgroup should be considered due to a much worse prognosis after alloHCT, although it remains mandatory in first complete response.

Assessment of 2022 European Leukemianet Risk Classification System in FLT3-ITD Positive Real-World Cohort from China

Background: The 2017 European LeukemiaNet (ELN-2017) risk classification system updated AML guidelines in 2022, adjusted FLT3-ITD mutated patients without core binding factor (CBF) or adverse risk markers to intermediate risk groups, according to the clinical trial results of midostaurin on patients with FLT3-ITD not NPM1 mutation and MRD in treatment decisions. However, midostaurin is not approved in mainland china; many patients in China are unable to receive FLT3 inhibitor due to highly cost yet. Methods: We include newly diagnosed de novo AML patients at our center from January 2017 to December 2021, regardless of the further treatment received. Patients with acute promyelocytic leukemia and AML with other previous myeloid neoplasms were excluded. All patients were diagnosed according to 2016 World Health Organization (WHO) criteria. Clinical data, chromosome and next-generation sequencing (NGS) results, treatment regimen and date of survival were included. Results: 408 patients were diagnosed as de novo AML (excluding M3) in our center, 364 patients have available cytogenetic and NGS data to access ELN-2022 risk classification. 137 (37.7%), 141 (38.8%) and 83 (23.5%) patients are classified into ELN-2022 favorable, intermediate and adverse risk groups, respectively, the median age of all patients at diagnosis is 52. 37 (10.2%) patients have a change in ELN risk classification compared with ELN-2017. In ELN-2017 favorable risk group, 19 patients whose FLT3-ITD allelic ratio <50% with NPM1 mutation are reclassified to ELN-2022 intermediate risk; in ELN-2017 intermediate risk group, five patients with CEBPA monoallelic bZIP mutation are reclassified to ELN-2022 favorable risk, 10 patients with MR gene mutations are reclassified to adverse risk; in ELN-2017 adverse risk group, 3 patients with FLT3-ITD allelic ratio >50% are reclassified to ELN-2022 intermediate risk. 323 (89.0%) patients received induction therapy: 271 (74.6%) patients received cytarabine-based chemotherapy, 52 (14.3%) patients unfit for intensive chemotherapy received hypomethylating agents (HMA)-based therapy, while 36 (9.9%) patients only received best supportive care, mainly due to early death during hydroxyurea treatment or did not want any therapy due to potential treatment costs. 211 (58.1%) patients received complete remission (CR), with CR rates in the ELN-2022 favorable, intermediate and adverse groups of 74.4%, 53.1% and 40.0%, respectively (p<0.001). After a median follow-up of 36.9 months, the median overall survival (OS) is 27.6 months, 10.6 months and 4.7 months in the ELN-2022 favorable, intermediate and adverse risk groups, compared to 21.9 months, 10.6 months and 4.8 months in the corresponding ELN-2017 risk groups. Patients in the ELN-2022 favorable group have a significantly better OS than those in intermediate and adverse group (p=0.002 and p<0.001), while there are no statistical differences between the intermediate and adverse groups (p=0.11), not significant as ELN-2017 (p=0.046). (Figure.1) 61 patients with FLT3-ITD mutations without adverse prognostic markers are classified as ELN-2022 intermediated risk. Among these patients, only 9 received FLT3 inhibitors (gilteritinib or sorafenib) due to late approval of FLT3 inhibitors in China; the remaining 52 patients received chemotherapy alone: 40 have FLT3-ITD allelic ratio <50%, 12 have allelic ratio ≥50%. These patients unable to receive FLT3 inhibitor did not achieve the same survival outcomes as other ELN-2022 intermediate risk patients (FLT3-ITD allelic ratio <50% group vs. intermediate risk group, p=0.046; FLT3-ITD allelic ratio >50% group vs. intermediate risk group, p=0.021); instead, both FLT3 mutated groups have no survival difference compare to the ELN-2022 adverse risk group. Moreover, for the ELN-2022 intermediate risk group without FLT3-ITD mutated patients, we find statistical difference to ELN-2022 adverse risk group on overall survival (median OS 17.6 months vs. 4.6 months, p=0.029), which is not achieved when FLT3-ITD mutated patients is included. (Figure.2) Conclusion: our real-world clinical data show that the ELN-2022 risk classification system is not superior to the ELN-2017 version in classifying patients in our center. For patients with FLT3-ITD mutation but unable to receive FLT3 inhibitor, their risk classification and treatment therapy should be considered as adverse risk group.

A Novel and Cost-Efficient Measurable Residual Disease (MRD) Detection Assay Using a Single Molecule Molecular Inversion Probe-Based Next Generation Sequencing (NGS) Assay Predicts Overall Survival in Patients with Acute Myeloid Leukemia Undergoing Allogeneic Stem Cell Transplantation

Introduction Relapse remains the main reason for poor outcomes of patients (pts) with acute myeloid leukemia (AML). Allogeneic hematopoietic stem cell transplantation (HSCT) is the preferred post-remission treatment in pts at high risk of relapse. The presence of measurable residual disease (MRD) after intensive frontline treatment or before or after HSCT has emerged as an important predictor of relapse. Various methods are used for MRD detection, including flow cytometry and molecular assays detecting individual gene mutations (mut) such as NPM1mut. Next generation sequencing (NGS)-based assays covering multiple genes commonly mutated in AML may allow sensitive MRD detection in a broad range of pts with diverse genetic characteristics. Methods We established a targeted, error corrected NGS MRD assay utilizing single-molecule molecular inversion probes (smMIPs). The smMIP protocol uses a hybridization-capture approach to selectively enrich and amplify both DNA strands of 92 regions in 32 genes in a single reaction. Unique molecular identifiers (UMIs) facilitate computational correction of sequencing errors to enable reliable detection of variants ≥0.5% variant allele frequency (VAF), with the additional advantage of relatively low reagent and sequencing costs of < $100 per sample. The smMIP assay was used to evaluate MRD status on pre-HSCT bone marrow samples from 98 AML pts who received an HSCT in first (n=83) or second (n=15) complete remission with or without count recovery. Median age at HSCT was 59 (range 20-75) years, 42% were female; 70% had de novo AML, 19% had an antecedent myeloid neoplasm and 11% had AML post cytotoxic therapy. European LeukemiaNet (ELN)-2022 risk groups at diagnosis were favorable in 11%, intermediate in 33%, adverse in 20% and unknown in 22%. All pts had received intensive induction chemotherapy. Twenty-nine percent received a myeloablative conditioning regimen (MAC), while 23% received reduced intensity conditioning (RIC) and 48% a non-myeloablative (NMA) conditioning regimen. Donors were matched related (18%), haploidentical (6%), or matched (55%) or mismatched (21%) unrelated. The median follow-up for pts alive was 34.8 months. Results Overall, we detected 190 variants in 71 (72%) of 98 pre-HSCT remission samples. The most commonly affected genes were DNMT3A (in 37% of pts), TET2 (21%), PPM1D (12%), IDH2 (10%) and TP53 (5%). Twenty-nine percent of pts had only variants affecting the clonal hematopoiesis-related genes DNMT3A, TET2 or ASXL1 (‘DTA‘), while 44% of patients had ≥1 variant involving a non-DTA gene. MRD-positive pts, defined as those with ≥1 non-DTA variant, had similar baseline and HSCT-related characteristics (includingage, sex, ELN risk group, de novo vs. secondary AML) compared to pts without non-DTA variants. Overall survival (OS) was significantly inferior in NGS MRD-positive pts compared to those with no non-DTA variant (Figure A, 5-year OS, 49% vs. 85%, P=.011). MRD-positive pts also had a non-significant higher cumulative incidence of relapse at 5 years (46% vs. 24%, P=.14), while non-relapse mortality was similar in both groups (P=.72). We next performed multivariable analyses, considering variables associated with OS at an univariable P<.10 (MRD status, patient sex, therapy-related AML, conditioning intensity), and using stepwise backward variable selection to identify factors significantly associated with OS (Figure B). In the final multivariable model, pre-HSCT MRD detection remained associated with inferior OS (hazard ratio 2.51; 95% confidence interval, 1.07 - 5.91; P=.035). Female sex associated with favorable OS, while myeloablative conditioning (MAC) showed a borderline significant association with superior OS. Of note, we did not detect an interaction between conditioning intensity and detection of MRD with regard to OS, i.e. the prognostic association of MRD detection was not different between pts receiving myeloablative or less-intensive conditioning. However, this analysis was limited by the small patient number. Conclusion Detection of MRD by targeted NGS using the smMIPs approach provides prognostic information in pts undergoing allogeneic HSCT, including those without established molecular markers such as NPM1mut. This method is applicable to a large proportion of AML pts and is cost-efficient for broad clinical use. S.M.K. and T.H., and M.J. and K.H.M. contributed equally to this abstract.

Treatment Outcomes of Stem Cell Transplant in Patients with Acute Myeloid Leukemia Treated with Venetoclax in Combination with Hypomethylating Agents: Experience from Routine Clinical Practices in the United States

Background: Venetoclax (Ven) in combination with hypomethylating agents (HMAs) is approved in the United States (US) for treatment in patients (pts) with newly diagnosed (ND) acute myeloid leukemia (AML) who are ≥75 years old or unfit for intensive chemotherapy. In a Phase Ib open-label trial (NCT02203773) and the Phase III VIALE-A trial (NCT02993523), a total of 33 pts with ND AML who were treated with Ven+HMAs underwent a stem cell transplant (SCT). The observed 12-month overall survival (OS) was 74.3% post-SCT, and the median OS was 29.9 months for pts who were in remission at the time of SCT (Pratz et al. EHA 2023). This study aims to evaluate the treatment patterns and outcomes of pts with ND AML treated with Ven+HMAs who underwent SCT post-remission from routine clinical practices in the US. Methods: This was a retrospective cohort study using the Flatiron Health electronic health record-derived, US nationwide, de-identified database. Pts aged ≥18 years with ND AML who initiated first-line Ven+HMAs treatment within 30 days from AML diagnosis (Dx) between July 1, 2018, and November 30, 2022, with ≥2 visits recorded within 3 months of AML Dx, and ≥3 months of potential data available before the study end date (February 28, 2023) were included. Pts with acute promyelocytic leukemia, t(9;22), treated with HMAs before AML Dx and pts who received Ven treatment more than 14 days prior to AML Dx were excluded. Descriptive analysis on patient characteristics was conducted. The proportion of pts who achieved real-world response (defined as <5% bone marrow [BM] blast), median time from Ven+HMAs treatment initiation to last administration (TTLA), and median time from Ven+HMAs initiation to SCT were reported. For pts who received SCT post-remission, 100-day real-world OS (rwOS), 12-month rwOS, and 15-month rwOS were evaluated using Kaplan-Meier analyses. The starting point of Kaplan-Meier analyses was SCT, and pts were censored at the last activity date. Results: Overall, 988 pts with ND AML treated with Ven+HMAs met the study criteria. A total of 51% (n=503/988) of pts achieved real-world response, of which 11% (n=57/503) subsequently underwent SCT post-remission. In pts with SCT post-remission (n=57) vs pts without SCT post-remission (n=446), the median age was 67 years vs 76 years, 30% (n=17/57) vs 30% (n=134/446) had secondary AML, and 60% (n=34/57) vs 24% (n=107/446) were treated at academic centers, respectively. Excluding pts with unknown cytogenetic and molecular data, the European LeukemiaNet (ELN) 2017 risk in pts with vs without SCT post-remission was favorable for 16% (n=7/43) vs 21% (n=76/355), intermediate for 33% (n=14/43) vs 26% (n=93/355), and adverse for 51% (n=22/43) vs 52% (n=186/355), respectively. Among pts with available molecular testing, FLT3 mutation in pts with SCT vs pts without SCT post-remission was 19% (n=5/26) vs 20% (n=48/245); IDH1/2 mutation was 33% (n=9/27) vs 35% (n=95/275); and TP53 mutation was 47% (n=9/19) vs 28% (n=54/192), respectively. Of the 57 pts who underwent SCT post-remission, the median (interquartile range [IQR]) TTLA on Ven+HMAs was 4.0 (3.0-5.3) months and the median (IQR) time from Ven+HMAs initiation to SCT was 5.4 (4.4-6.8) months. At a median follow-up of 8 months from SCT post-remission, the 100-day rwOS was 92%, 12-month rwOS was 52%, 15-month rwOS was 49%, and the median rwOS was 13.0 (95% confidence interval: 8.2-not reached) months ( Figure). Conclusions: In this study, similar to findings from clinical trials, we observed a subset of pts with ND AML treated with Ven+HMAs underwent SCT post-remission in routine clinical setting. Compared with pts who did not undergo SCT post-remission, pts who underwent SCT post-remission were younger, and more of these pts received care in academic centers. Of the Ven+HMAs-treated pts who underwent SCT post-remission, more pts treated in the routine clinical setting had the poor prognostic TP53 mutation than pts enrolled in the aforementioned clinical trials. In this study, most pts remained alive 100 days after SCT. The rwOS results observed in this study suggest that Ven+HMAs post-remission is a potential bridge to SCT in pts who are ineligible for intensive chemotherapy.

BCOR Loss Confers Increased Stemness and Partially Rescues RUNX1-Deficient Phenotypes in Human Hematopoietic Stem and Progenitor Cells

Introduction: Loss of function mutations in BCL-6 corepressor (BCOR) commonly occur in de novo acute myeloid leukemia (AML) and germline hematopoietic malignancies, most notably in those arising from RUNX1 familial platelet disorder (RUNX1-FPD). Second only to loss of heterozygosity of RUNX1, mutations in BCOR are the most commonly acquired mutations upon progression to myeloid malignancy in RUNX1-FPD. Additionally, RUNX1 and BCOR mutations commonly co-occur in de novo AML, and both are classified as “adverse risk” by the European LeukemiaNet if found at AML diagnosis. However, the role of BCOR in leukemogenesis is poorly understood, and there are limited studies investigating co-loss of BCOR and RUNX1 in hematopoietic stem and progenitor cells (HSPCs). Methods: We developed a model of BCOR loss in primary human CD34+ HSPCs using CRISPR/Cas9 and AAV6-mediated homology directed repair to knock-in a fluorescent reporter expression cassette into the BCOR locus. We used this system to investigate how BCOR knockout (KO) perturbs normal HSPC function. We combined this approach with a previously developed analogous system to disrupt the RUNX1 locus to investigatehow BCOR loss in the setting of RUNX1 KO modulates the effects of RUNX1 loss on HSPC function. Results: Here, we found that BCOR loss increased capacity for serial replating and conferred a competitive advantage over control HSPCs. In serial replating assays, BCOR-deficient HSPCs had a 5-fold increase in colony formation after one passage with a striking majority of colonies being erythroid. In liquid differentiation assays, BCOR-deficient HSPCs consistently had a 2-fold increase in CD34+ cells over a 21 day time course. When co-cultured with control HSPCs in a 1:1 ratio in stem expansion media (base media + SCF, FLT3-L, TPO, IL-6, UM-171), BCOR-deficient HSPCs expanded to comprise 70% of the culture at 14 days. This competitive advantage was recapitulated in vivo. At the 12-week timepoint of a competitive transplantation assay in NSG mice using HSPCs from 3 different donors, BCOR KO cells (marked by BFP) on average made up 75% of the engrafted human CD45+ population, while control cells (expressing GFP from the AAVS1 safe harbor locus) made up only 21%. Additionally, BCOR loss partially rescued RUNX1-induced stem cell dysfunction in vitro. Compared to RUNX1 deficiency alone, HSPCs deficient in both RUNX1 and BCOR had a 4-fold increase in colony formation after two passages in serial replating assays. Our lab has previously shown that RUNX1 loss ablates erythroid colony formation and skews towards monocytic colonies. Despite BCOR loss alone having a strong skew towards erythroid colonies, BCOR loss in RUNX1-deficient HSPCs did not induce erythroid colony formation. This suggests that in double mutant HSPCs, RUNX1 loss drives lineage decisions while BCOR loss drives the increase in serial replating potential. Ongoing efforts are aimed at characterizing combinatorial effects of BCOR and RUNX1 loss on hematopoiesis and stem cell function through in vitro liquid differentiation assays and in vivo transplantations, as well as investigating the molecular underpinnings of these phenotypes through RNA-seq. Conclusion: In summary, we have established a model of BCOR loss in primary human HSPCs to evaluate not only the role of BCOR in hematopoiesis, but also to characterize how BCOR is involved in leukemic transformation when combined with RUNX1. We show that BCOR deficiency enhances several attributes associated with stem cell function, including increased potential for serial replating, increased CD34 positive population, and increased engraftment compared to control HSPCs. When combined with RUNX1 loss, BCOR loss increases the serial replating potential of RUNX1-deficient cells, suggesting some rescue of RUNX1 KO-induced stem cell dysfunction. Ultimately, this model will enable us to elucidate the molecular mechanisms underlying increased stemness and competitive advantage in BCOR-deficient HSPCs, interrogate RUNX1-FPD disease progression associated with BCOR mutation, and validate potential therapeutics.

Psychiatric and Substance Use Disorders Are Independent Predictors of Treatment Response and Outcomes in United States Veterans with Newly Diagnosed Acute Myeloid Leukemia Treated with Venetoclax Combinations

BACKGROUND: Venetoclax (VEN) combinations have become the standard frontline therapy for patients with newly diagnosed acute myeloid leukemia (AML) who are deemed unable to tolerate intensive induction chemotherapy, either due to age or comorbidities. However, outcomes in the real-world setting have been inferior to those observed in clinical trials. Preexisting psychiatric diagnoses and substance use disorders (SUDs) have previously been associated with increased mortality in patients with cancer, but their prognostic influence in veterans with AML is unclear. The aim of this study was to measure the prevalence of psychiatric and SUDs in veterans with AML treated with VEN combinations, determining the impact of these conditions on treatment response and outcomes. METHODS: This was a retrospective cohort study of veterans with newly diagnosed AML who received frontline therapy with VEN combinations within the national Veterans Affairs (VA) Healthcare System. To measure the prevalence of psychiatric and SUDs, we used the Centers for Medicare and Medicaid Services (CMS) Chronic Conditions Data Warehouse algorithm, which tracks health conditions by administrative claims data with International Classification of Diseases (ICD) diagnostic and procedural codes. Our endpoints were rates of complete remission or complete remission with incomplete marrow recovery (CR/CRi), early mortality (EM, or death within 60 days of treatment initiation), intensive care unit (ICU) admissions, and overall survival (OS). We evaluated the relationship between comorbid medical conditions and outcomes using Kaplan-Meier analysis and Cox proportional hazards regression models, first unadjusted, and then adjusted for all covariates. Patients who underwent allogeneic stem cell transplantation (HSCT) were excluded from statistical analyses. RESULTS: We identified 452 veterans treated with VEN up to April 1, 2022 (Table 1). In combination with VEN, 60% (n=270) received azacitadine, 37% (n=168) received decitabine, and 3% (n=14) received low-dose cytarabine. Median age was 74.3 years (IQR: 71.2-78.5) with 52% ≥75 years. By European LeukemiaNet (ELN) 2017 risk classification, 61% (n=274) were classified as adverse risk. Forty-six percent (n=206) of veterans had a preexisting psychiatric diagnosis, and 19% (n=84) had SUDs; 11% (n=49) had both comorbidities. Psychiatric disorders were significantly more prevalent in younger veterans (68% in <65 years vs 50% in 65-74 years vs 39% in ≥75 years, p<0.003); same was true for SUDs (38% in <65 years vs 26% in 65-74 years vs 9% in ≥75 years, p<0.001). For the entire cohort, CR/CRi was achieved by 57% (n=257), and only 3% (n=12) received HSCT. Zero veterans with SUDs and 8 with psychiatric diagnoses were transplanted. At the end of study period, 69% (n=310) had died. Median OS was 216 days (95% CI: 195-254). The 60-day mortality rate was 20% (n=87), of which 8 veterans had primary refractory AML. ICU admissions after treatment initiation was significantly higher in veterans with SUDs compared to those without history of SUDs (5.0 versus 2.2 per 5 person-years, p<0.001). On multivariable analyses (Table 2), both psychiatric and SUDs were independently associated with decreased odds of CR/CRi. Veterans with psychiatric disturbances had a 1.97 times higher hazard of EM (95% CI: 1.16-3.39, p=0.01) and a 1.28 times higher hazard of death (95% CI: 1.00-1.64, p=0.05) compared to veterans without concurrent psychiatric disorders. CONCLUSION: Psychiatric diagnoses and SUDs were not only prevalent among veterans with AML, but they also negatively impacted treatment response, EM, and OS-independently of age, sociodemographic variables, markers of disease risk, and VEN combination. Veterans with SUDs also had significantly higher ICU admissions after treatment initiation for AML. Compared to published clinical trials data, veterans experienced inferior outcomes. Veterans with psychiatric and SUDs may have difficulty adhering to regimens, reemergence of their mental instability and illness that is triggered by AML diagnosis and its treatment, or biologic mechanisms associated with these comorbidities. Better understanding of these factors contributing to health disparities and targeting these comorbidities with supportive care interventions alongside AML-specific therapy may improve outcomes and warrant further study.

A Phase 1A/B Combination Study of Pegargiminase (ADI-PEG 20), Venetoclax and Azacitidine in Patients with Acute Myeloid Leukemia

Background and Significance: Outcomes for adverse-risk acute myeloid leukemia (AML), especially in older and/or unfit patients and those with relapsed/refractory disease, remain poor despite several new drug approvals over the last decade. A promising area for drug development in AML resides in targeting tumor metabolism. The metabolism therapy of pegargiminase (ADI-PEG 20), an agent consisting of the arginine-degrading enzyme arginine deiminase combined with polyethylene glycol, has demonstrated preclinical and clinical efficacy as monotherapy and in combination in AML. ADI-PEG 20 has been shown to be most effective when tumors are deficient in argininosuccinate synthetase (ASS1), the rate limiting step in the urea cycle to form arginine. AML is one such cancer, which appears to be addicted to arginine, with about 90% of AML patient samples being deficient in ASS1 expression. The focus of this phase 1A/B study is to explore combination treatment with ADI-PEG 20 added to standard front-line venetoclax and azacitidine therapy in AML. Study Design and Methods: This study (NCT05001828) is an open label, single arm, multicenter phase 1 trial for patients with newly diagnosed adverse-risk AML unfit for intensive chemotherapy or relapsed/refractory AML. Eligible patients must be ≥18 years old and are ineligible if determined favorable-risk by European LeukemiaNet (ELN) criteria. The primary objective is to determine the recommended phase 2 dose (RP2D) of ADI-PEG 20 administered by intramuscular injection weekly in combination with venetoclax and azacitidine. Secondary objectives include evaluating preliminary evidence of antitumor activity and determining the pharmacodynamics and immunogenicity of ADI-PEG 20 in combination with venetoclax and azacitidine. Patients receive ADI-PEG 20 via intramuscular injection on day -3 and then weekly along with the combination regimen of azacitidine 75 mg/m 2 for 7 days and oral venetoclax on days 1-28 of the first cycle and days 1-21 for subsequent cycles. Subjects may remain on study treatment for a maximum of 24 cycles (96 weeks). The study is designed with a lead-in group exploring 2 dose levels of ADI-PEG 20 and an RP2D expansion group with 18 subjects each in 2 cohorts: Cohort 1 including previously treated (relapsed/recurrent) or refractory AML and Cohort 2 including untreated AML with high-risk features and ineligible for intensive chemotherapy. In total, 48 to 60 subjects are planned across up to 5 centers in the United States. In the RP2D cohorts, the target response rates for the relapsed/refractory and untreated AML with high-risk features are 25% and 55%, respectively. Safety is assessed by comparing adverse events, laboratory results, and physical examination results. A greater than 20% clinically significant drug-related grade 3 or higher toxicity rate occurring in the first cycle is considered unacceptable. To assess efficacy, the number and percent of subjects' objective response rate, duration of response, and overall survival (OS) will be summarized. Pharmacodynamics using peripheral blood arginine and citrulline levels will be summarized for all subjects by time point for the observed value as well as for the change from baseline value and by duration of arginine depletion and citrulline increase. Immunogenicity, determined by antibodies to ADI-PEG 20, will be summarized for all subjects by time point for the observed value as well as for the change from baseline value. Semiquantitative assessment of ASS1 expression by immunoblots and/or immunohistochemistry or other appropriate means will be summarized descriptively. Demographics, clinical characteristics (including duration of response), and safety data of the patients will be summarized using descriptive statistics. For the efficacy analysis, we will estimate the response rate along with the 95% credible interval. The association between response and patient's clinical characteristics will be examined by Wilcoxon's rank sum test or Fisher's exact test, as appropriate. The distribution of time-to-event endpoints, such as OS and others, will be estimated using the method of Kaplan and Meier. Comparisons of time-to-event endpoints by important subgroups will be made using the log-rank tests. The trial is currently enrolling and presents a novel and promising therapeutic strategy for patients with high-risk newly diagnosed and relapsed/refractory AML.

Neighborhood Disadvantage Is Associated with Inferior Overall Survival for Acute Myeloid Leukemia Patients Treated with Standard Intensive Induction

Background: Identifying biologic and socioeconomic contributors to disparities in outcomes is critical for the management of acute myeloid leukemia (AML). Prior studies in AML revealed that Black patients (pts) have inferior survival compared to White pts, with more striking disparity for Black pts aged <60. We previously explored our large and diverse AML cohort from urban and large rural areas and did not identify inferior survival for pts with self-reported Black race or Hispanic ethnicity. Although no surrogates for social determinants of health (SDOH) or insurance status were recognized as contributing to survival differences, oncology nurse navigation (ONN) was associated with a survival benefit, with no significant difference in access to ONN among racial or ethnic groups. To further evaluate socioeconomic drivers of disparities in this population supported by ONN, we aim to use the Area Deprivation Index (ADI) to determine the impact of neighborhood disadvantage on survival in AML. Methods: AMLpts diagnosed at Levine Cancer Institute between 12/2015 and 12/2020 were included. Pts with acute promyelocytic leukemia (APL) were excluded from this analysis. Details regarding insurance coverage, ONN services, induction therapy, stem cell transplant (SCT) status, and survival outcomes were collected. Race and ethnicity were self-reported. European LeukemiaNet (ELN) 2017 criteria were used to assign AML risk. Pt and disease characteristics were summarized, described, and compared with Fisher exact tests and Wilcoxon rank-sum tests for categorical and continuous data, respectively. Pts were grouped into 4 quartiles based on ADI national percentile. Subsequent models were fit with ADI dichotomized at the median after adjacent ADI groups were removed with backward elimination. Associations between overall survival (OS) and pt and disease characteristics, insurance status, race, ethnicity, ONN services, and ADI were investigated. OS was defined as the time from diagnosis (dx) to death from any cause, with surviving subjects censored at the time of last follow-up. Kaplan-Meier methods were used to summarize OS and calculate landmark survival rates. Survival was compared with unadjusted log-rank tests. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CIs) associated with OS. Results: Three hundred eighty pts with available baseline characteristics were included in our analysis ( Table 1) . For pts <60 who received intensive induction and had available ADI (N=86), there was a significant difference in OS amongst the quartiles of ADI (P=0.007), with differences even more pronounced with dichotomized ADI (P<0.001) ( Figure 1). With a median follow-up of 38.1 months for the intensively treated pts <60, the estimated two-year OS was 96.6% for more advantaged/low ADI pts and 55.4% for less advantaged/high ADI pts (HR 5.21; 95% CI 1.82 to 14.95). Within the cohort of pts <60 who received intensive induction, sixty-eight percent were Non-Hispanic White and 28% were Non-Hispanic Black. Many (66%) were privately insured at dx, with 24% uninsured or with Medicaid. ONN services were accessed by most (72%) pts with known ADI. Care barriers were expressed by pts of all ADI quartiles, with transportation being the only barrier most reported by pts of increased disadvantage (P<0.01). Forty-two percent of pts received SCT (N=38). Nearly 60% of socially advantaged pts (ADI≤51) received SCT versus 33% of socially disadvantaged pts (P=0.03). In univariate models, receipt of SCT (P=0.016) was associated with improved OS while receiving navigation services (P=0.32) was not. Conclusions: Higher ADI was associated with inferior OS in AML pts <60 who received intensive induction. Receipt of SCT was observed more often in pts with more neighborhood advantage, which is of great importance since SCT improved OS in this cohort. Although insurance status is often linked to SCT access, insurance status did not significantly impact OS. Of the ONN reported barriers to care, transportation issues had a greater impact on pts with more neighborhood disadvantage. Expanding access to SCT and addressing barriers to care, such as transportation, is necessary to overcome the detrimental impact of neighborhood disadvantage on survival in AML.

Outcomes of Extramedullary Acute Myeloid Leukemia with Gemtuzumab Ozogamicin: Real-World Experience

Introduction: Extramedullary AML (EM AML) is characterized by the presence of leukemic cells in organs or tissues outside of the blood or bone marrow and remains a therapeutic challenge with dismal response rates to standard chemotherapy and short overall survival. Gemtuzumab Ozogamicin (GO) is an anti-CD33 antibody drug conjugate currently approved for single-agent therapy or in combination regimens for CD33+ relapsed/refractory (R/R) or newly diagnosed (ND) AML, respectively. Although GO is an active drug in AML, the optimal employment of this agent for treatment of EM AML at initial diagnosis, or at relapse, remains to be defined. Methods: A retrospective chart review on outcomes of GO in adults with EM AML at our institute from 2000 to 2023 was performed. Variables collected included age, sex, type of myeloid malignancy, and European LeukemiaNet (ELN) risk, bone marrow, peripheral blood and radiographic involvement, Response Evaluation Criteria in Solid Tumors (RECIST), prior lines of treatments, including stem cell transplant, next-generation sequencing (NGS), cytogenetics, mutational profile, and overall survival (OS). We screened patients with a diagnosis of EM AML who received GO at any point during their EM AML therapy. Patients with only CNS involvement as the extramedullary site were excluded. The aims of this study were to characterize responses and potential clinical benefit of EM AML to GO based regimens in the upfront and R/R settings. Results: 32 patients(pts) with EM AML received GO: 8 (25%) were ND and received GO-based induction regimen, while 22 (68.75%) received GO for R/R AML, and 2 (6.25%) patients received GO both at initial diagnosis and relapse. The median age of patient with ND EM AML was 66 years (y) (range: 28-84), and 60.5 (43-73) y in R/R EM AML. Twenty-four (75%) were men. One (12.5%) ND EM AML and 5 (10.1%) R/R EM AML had >1 extramedullary sites involved. The most frequent sites of EM-AML were skin (25%), lymph nodes (25%), soft tissues (25%), solid organs (25%), and visceral body cavity fluids (12.5%). Based on ELN 2022 risk group criteria, 17 patients were adverse, 8 with intermediate, and 3 with favorable risk. Next-Generation Sequencing (NGS) available for 21 patients identified mutations in TP53 (14.28%), FLT3 (19.04%), NPM1 (19.04%), KMT2A (19.04%), and ASXL1 (19.04%) as the most common mutations. Normal karyotype was noted in 6 (25%) R/R EM AML, while complex karyotype was present in 1 (12.5%) ND EM AML and 10 (41.67%) of R/R EM AML. While none of the ND pts had prior myeloid malignancy, R/R pts had prior AML (15), MDS (2), MDS-EB (1), CMML (1), therapy-related AML (1), myelofibrosis (1), and myeloid sarcoma (1). Concomitant bone marrow involvement at identification of EM AML was present in most ND cases (7/8, 88%) and R/R settings (16/23, 69.56%) (Table 1). Combination 7+3 plus GO was most frequently administered for ND EM AML (3/8) and R/R EM AML (8/24, 33%). Eleven patients had measurable radiologic findings prior to and following GO. Median OS was 10.91 months (m) (range: 0.2 to 27.1) for ND EM AML and 1.58 m (range: 0.7 to 7.5) for R/R EM-AML (Figure 1). 3 of 8 newly diagnosed EM-AML underwent allogeneic bone marrow transplant (AlloBMT) after GO based induction, followed by relapsed EM AML in 1 patient. Despite 50 percent of R/R EM AML pts undergoing prior AlloBMT, none had a durable disease-free response and received GO after relapse. Based on RECIST criteria, 7 of 11 (63.63%) pts achieved a response including 1 Complete Response (disappearance of all target lesions), 6 Partial Response (at least a 30% decrease in the sum of target lesions), and 2 Stable Disease (neither sufficient shrinkage nor increase). The 30-day mortality for ND and R/R were 12.5% and 8.33%, respectively. The 60-day mortality for ND and R/R were 25% and 50%, respectively. Conclusion: Our real-world single-institute experience in patients with EM AML suggests that GO combined with chemotherapy in the upfront setting results in promising outcomes with high overall response rates (CR 50%, PR 13%) by RECIST criteria, durable remissions, and prolonged overall survival in largely favorable and intermediate risk AML. However, despite high partial response rates (4% CR, 50% PR) following GO-based therapy in R/R EM AML, survival was less than 2 months likely due to the high proportion of patients in this cohort with poor risk disease. Further investigations and larger studies are warranted to establish the optimal use of GO in EM AML.

The Methylome Atlas of Acute Leukemia Enables Novel Clinical Diagnostic Tool for AML

In 2022, both the World Health Organization (WHO) and the European LeukemiaNet (ELN) highlighted the formidable challenges of categorizing certain Acute Leukemia subtypes, such as AML with rare recurring translocations, complex karyotypes, not otherwise specified, and myelodysplastic-like entities. As characterizations of new variants and fusion partners become more prevalent, it is difficult to assess which ones, alone or in combination, generate which leukemia phenotypes. To that end, WHO posed methylation profiling as “the technology at present best suited for addressing lineage and thereby the cell population of origin of tumors” (PMID: 34921008), which invites an opportunity to evaluate the DNA methylome as a clinical diagnostic avenue in hematopoietic malignancies like AML. Thus, we hypothesize that the DNA methylome holds promise in further refining AML classification. In this study we describe the assembly of the largest publicly available methylation dataset of acute leukemias so far, which combines 11 high-quality clinical trials/studies: NOPHO ALL92-2000 (n=796), AAML0531 (n=628), AAML1031 (n=581), BeatAML (n=316), TCGA AML (n=194), French GRAALL 2003-2005 (n=153), TARGET ALL (n=131), CETLAM SMD-09 (n=83), AAML03P1 (n=72), Japanese AML05 (n=64), and CCG2961 (n=41), resulting in a total of 3,059 subjects after preprocessing. Samples were obtained either from bone marrow or peripheral blood, with DNA methylation (meDNA) data procured using the Illumina methylation array 450k or EPIC array, which share 452,453 probes with same chemistry and design. To independently validate the findings derived from the discovery cohort, we processed in parallel meDNA array data from bone marrow specimens at diagnosis of AML patients treated on the multi-center clinical trials AML02 (n=159) and AML08 (n=42) led by St. Jude Children's Research Hospital. Processing the raw data followed best practices from the literature using SeSAMe (PMID: 30085201, 27924034). To generate the atlas, we used a novel dimensionality reduction unsupervised learning algorithm called Pairwise Controlled Manifold Approximation (PaCMAP), which allowed compression of 319,738 processed CpG values into two components for visualization (Figure 1) and five components for downstream classification analysis. To empirically assess classification accuracy of PaCMAP results, we implemented a machine learning pipeline with hyperparameter tuning, 10-fold cross validation, and assessed accuracy per class in discovery and validation cohorts. Not all samples, however, had clinical diagnostic annotation available in the dataset, so only those with the annotations were used in the supervised machine learning model (n=1399 in discovery and n=110 in validation). Our resulting atlas unveils several clusters of samples that defined 6 hematopoietic lineages: AML, ALL, MDS-related or secondary myeloid neoplasms (MDS-like), Acute promyelocytic leukemia (APL), mixed phenotype leukemia, and otherwise-normal control. These are further subdivided into 30 subclasses overlapping with WHO 2022 and ELN 2022 clinical diagnostic annotations. Subsequent analyses comparing methylation-based subtype prediction to clinically annotated subtypes revealed an overall concordance score of 0.936, with per class 10-fold CV concordance ranging from 0.82 for MDS-like to 1.00 in APL and NUP214 fusions. Importantly, the validation (test) cohort showed accuracies per class of 0.91 for AML with KMT2A-r (n=47) and 1.00 for AML rare recurring translocations (n=10). These are subtypes with large genomic heterogeneity that may be better represented at the epigenomic level. Additionally, these are largely considered standard to high-risk groups with poor prognosis, which invites further studies aiming at uncovering the biological mechanisms behind the methylation patterns governing this classification. Finally, the resulting classifier allowed prediction of WHO/ELN clinical diagnosis for 91 samples in the validation cohort that were previously categorized as “Normal Karyotype”, “Other” or blank. In conclusion, our study effectively showcases the use of a methylome atlas in enhancing the diagnosis of AML subtypes.

Pre-Transplant Somatic Co-Occurring Mutations (by next generation sequencing) in Acute Myeloid Leukemia: Frequency and Impact on Clinical Outcomes after Allogeneic Hematopoietic Cell Transplantation - a Large Study on Behalf of the EBMT Acute Leukemia Working Party

Background: Acute myeloid leukemia (AML) is a very heterogeneous hematological malignancy, which includes numerous genetically defined subsets. The genomic classification of AML with the identification of mutations in transcription factors, epigenetic modifiers, spliceosome, cohesin complex, and signaling pathways has led to a more accurate risk stratification model. The main genetic aberrations included in the European LeukemiaNet (ELN) 2022 classification are NPM1 (risk group according to karyotype and FLT3-ITD status), FLT3-ITD (intermediate risk), bZIP in-frame mutated CEBPA (favorable risk), and RUNX1, ASXL1, BCOR, EZH2, RUNX1, SF3B1, SRSF2, STAG2, U2AF1, ZRSR2 and TP53 mutations (all belonging to the adverse risk group). In the context of allogeneic hematopoietic stem cell transplantation (allo-HSCT), the frequency and prognostic value of different gene-gene interactions has not been studied and may differ from that of patients treated with chemotherapy alone. We aimed at evaluating, through the European Society for Blood and Marrow Transplantation (EBMT) database, the frequency and impact of different recurrent somatic mutations, either alone or in association, on prediction of relapse and survival in patients receiving allo-HSCT. Methods: This is a retrospective, registry-based, multicenter analysis from the EBMT with the approval of the EBMT Acute Leukemia Working Party. Adult patients aged more than 18 years with a diagnosis ofAML who received an allo-HSCT between 2013-2022, with an available genetic profile determined at diagnosis by next generation sequencing (NGS) were included. Results: We identified 836 allografted AML patients who had NGS performed at diagnosis. Most of these patients had de novo AML (88%), with a median age of 53 years (range: 18-78 years). Karyotype was favorable in 7%, intermediate in 69% and adverse in 24% of patients. At transplant, 74% of patients were in first remission (CR1) and 13% in CR2. The most frequent detectable mutations by frequency were DNMT3A (33%), FLT3 (29%), NPM1 (29%), TET2 (28%), NRAS (23%), RUNX1 (22%), WT1 (22%), BCOR (19%), ASXL1 (17%), IDH2 (17%), IDH1 (15%), SRSF2 (13%), STAG2 (12%), CEBPA (11%), TP53 (10%), KRAS (10%), and PTPN11 (10%) . By multiple correspondence analysis, two independent groups of co-occurring mutations were identified, the first group included DNMT3A, NPM1 and FLT3, the second group included ASXL1, SRSF2 and RUNX1. Outcome analysis was performed on the subset of 298 patients allografted in CR1 with available data for the aforementioned six genes ( DNMT3A, NPM1, FLT3, ASXL1, SRSF2 and RUNX1). Most of these patients had de novo AML (90%), with a median age of 53 years (range: 19-75 years). Patients received primarily reduced intensity conditioning (58%) and peripheral blood stem cells (93%) from matched sibling donors (35%), matched unrelated (28%), and haploidentical donors (21%). Seventy percent of these patients had intermediate-risk cytogenetics, while 27% were classified as adverse-risk. Median follow up calculated by the reverse Kaplan-Meier method was 2.5 years. Overall, the 2-year relapse incidence (RI), leukemia-free survival (LFS) and overall survival (OS) were 24%, 62% and 69%, respectively. When outcome analysis was performed according to the presence or absence of single mutations, none of the six mutations significantly affected RI or LFS. The 2-year OS was positively affected by the presence of NPM1 mutation (78% vs 66%; p=0.02) and FLT3 (79% vs 65%, p=0.01) but not significantly affected by the other 4 mutations. When mutations were investigated in groups, the 2-year RI, LFS and OS were 24%, 70% and 78%, respectively, for patients with NPM1 mutation regardless of other co-mutations, 35%, 56% and 69% for patients with FLT3-ITDand/or DNMT3A mutation, wild type NPM1, regardless of other co-mutations, 17%, 70% and 74% for patients with RUNX1 and/or ASXL1 and/or SRSF2 mutation without FLT3-ITD and with wild type NPM1 and wild type DNMT3A and 20%, 56% and 61% for patients with all six genes unmutated. Conclusion: NGS at diagnosis can be extremely useful in risk stratification of AML patients undergoing allo-HSCT, potentially allowing adequate post-transplant interventions. Notably, the 2-year LFS of 70% for patients harboring RUNX1 and/or ASXL1 and/or SRSF2 mutation indicates that allo-HSCT can overcome the adverse risk associated with these somatic mutations at diagnosis.

The Occurrence of Infection and TP53 Mutation Are Risk Factors for Cardiovascular Toxicity of Acute Myeloid Leukemia Induction Therapy

Introduction: For almost 50 years,induction therapy (IT) is the standard of care for acute myeloid leukemia (AML) patients. Nevertheless, little is known about cardiovascular (CV) toxicity during IT. We aimed to describe CV events (CVE)occurring during IT and to identify clinical, hematological and molecular risk factors of such events. Methods: Two hundred and twenty-four patients of 18 years or more (median age 61 (51;67) years, 58% males), treated with ITbetween 2014 and 2021 were enrolled in this study. Two hundred and one (90%) received an anthracycline-based IT, the others received gemtuzumab ozogamicin as part of a clinical protocol research. Survival from the time from initiation of IT until death or until the initiation of the second course of therapy (either salvage regimen in case of primary refractory or relapsed AML, or intensive consolidation therapy in case of response) was considered. The primary endpoint was the time to occurrence of the first CVE after IT initiation, with death as a competing event. Multivariate analysis included significant covariate, identified by univariate models among initial characteristics and occurrence of infection (coded as time dependent covariate). Results: Hematological characteristics were as follows: European LeukemiaNet (ELN) 2022 risk of myelodysplastic neoplasm (MDS)/AML was low, intermediate and adverse in 13%, 29% and 58% of patients respectively. Main mutations encounters were: DNMT3A, FLT3, NPM1, TET2, NRAS, RUNX1, ASXL1, IDH2, PTPN11, BCOR, SRSF2, WT1 and TP53. Main CV risk factors were tobacco (36%), arterial hypertension (35%), obesity (24%), hyperlipidemia (22%), diabetes mellitus (11%). Baseline left ventricular ejection fraction (assessed by transthoracic echocardiography) was >45% in all patients, >55% in 95% of patients. Seventy-five patients (33%) presented a CVE during IT. Eighty-six percent of CVE were severe (grade 3 or more). Patients presenting CVE during IT were significantly older (p=0.02) and presented more often a past history of dilated cardiomyopathy (p=0.04), arterial hypertension (p=0.005) or dyslipidemia (p=0.005). At baseline, CVE patients presented a greater left auricle volume (p=0.005), higher tricuspid regurgitation grade (p=0.01), and more often a right ventricular dilatation or a significative valvopathy (respectively p=0.01 and p=0.03). There was no difference in CVE occurrence between patients treated with and without anthracyclin (p=0.2). Competing risk models identified the following adverse characteristic for the risk of first CVE, namely the occurrence of the first infectious event (Hazard ratio [HR]= 2.43, p=0.005), TP53 mutation (HR=1.79, p=0.04). No other clinical characteristics nor mutation (including TET2 and DNMT3A) were identified. Multivariate analyses demonstrated that TP53 mutation (HR=1.78, p=0.04) and occurrence of infection (HR=2.29, p=0.008) retained independent prognostic value, see Table 1. In a response stratified model, only TP53 mutation was a risk factor of first CVE (HR=2.46, p=0.008). Conclusions: CVE occurred in 33% of patients during IT and were severe. The major adverse role of onset of infection for CVE occurrence after IT could overcome the prognostic value of mutations usually associated with CV risk in the healthy population (i.e. TET2, DNMT3A, ASXL1, ...). TP53 mutation was the only molecular abnormality associated with CVE, in agreement with the increased risk of doxorubicin-induced cardiac toxicity in a mouse model of TP53 clonal hematopoiesis developed by Sano et al. These results suggest that TP53 mutated patients could benefit from careful CV monitoring and optimization of primary prevention treatment.

High PD-L1 Expression May be Associated with Worse Overall Prognosis in Acute Myeloid Leukemia

Background: PD-L1 expression has been explored in solid tumours and in classical Hodgkin's lymphoma, however its expression in acute leukemias has been minimally studied. PD-L1 over-expression in AML blasts has previously been associated with worse outcomes in patients with mutated FTL3 genes, and positively correlated with TP53 expression. Over-expression of PD-L1 may contribute to failed response to hypo-methylating agents, leading to the rationale behind combination therapy with immune-checkpoint inhibitors. Despite evidence that the PD-1/PDL-1 axis may promote myeloid neoplasms by modulating immune escape, clinical trials studying the role of immunotherapy in MDS/AML have produced disappointing results. The lack of evidence to support the role of PD-1-targeted therapy in AML may be due to lack of identification of the subset of patients who may benefit from immunotherapy. We previously demonstrated that PD-L1 expression is significantly enhanced in patients with JAK2/STAT mutations compared to patients with wild-type (WT) JAK2/STAT. Here, we investigate the clinical correlate of our findings and compare clinical outcomes of AML patients with respect to PD-L1 expression. Methods: Immunohistochemical staining for PD-L1 was previously performed on bone marrow biopsies of 31 AML patients, including 11 patients with JAK2/STAT mutations (nine with JAK2 V617F exon 14 mutations, one with JAK2 I540-E543delinsRG exon 12 mutation and one with STAT5B N642H mutation) and 20 patients with WT JAK2/STAT. PD-L1 CPS was calculated by summation of all PD-L1-stained cells divided by total number of tumour cells, and multiplied by 100. Retrospective chart review was performed to extract data regarding patient demographics, cytogenetics, mutations, treatment course, as well as clinical outcomes. Low and high PD-L1 expression was defined as CPS score <10 and > 20 respectively. Kaplan-Meier analysis was used for analysing overall survival (OS) and event-free survival (EFS), with statistical significance determined using a 2-tailed log-rank test. EFS was defined as duration of time between diagnosis and the first occurrence of either going off protocol induction without achieving complete remission (CR), relapse from CR, or death due to any cause. Patients who were alive at the time of study analysis were censored at date of last follow-up. Results: A total 15 patients demonstrated high PD-L1 expression (lowest PD-L1 CPS 20), including four patients with WT JAK2/STAT and all 11 patients with mutant JAK2/STAT. 16 patients demonstrated low PD-L1 expression (highest PD-L1 CPS 6). Only three patients in the low PD-L1 expression group never achieved complete remission compared to eight patients in the high PD-L1 expression group. Median OS in the low PD-L1 expression group was significantly longer than median OS in the high PD-L1 expression group (29.1 months [95% CI 1.4-7.2] vs 9.3 months [95% CI 0.1-0.7]; HR 2.4 [95% CI 1.1-5.6], p = 0.0253, Figure 1). Similarity, EFS was significantly longer in the low PD-L1 expression group (13.1 months [95% CI 1.3-6.7] vs. 4.4 months [95% CI 0.1-0.8]; HR 2.4 [95% CI 1.1-5.6], p = 0.0253). When analysis was separated by European LeukemiaNet (ELN) risk stratification, significant differences in OS and EFS were re-demonstrated in patients with favourable ELN risk, but not in patients with intermediate or adverse risks. When wild-type JAK2/STAT patients were analyzed separately, there was no significant differences between OS and EFS with respect to PD-L1 expression. Conclusions: We previously demonstrated that PD-L1 is significantly up-regulated in AML patients who carry mutant JAK2/STAT when compared to WT JAK2. Using a proposed PD-L1 CPS cut-off score of 20, we demonstrated that high PD-L1 expression was associated with significantly worse outcomes with respect to OS and EFS. These results may indicate a therapeutic role of immunotherapy in the treatment of AML, particularly in patients with JAK2/STAT mutations.

Validation of the Prognostic Risk Signatures for Older Patients with Acute Myeloid Leukemia Treated with Hypomethylating Agents and Venetoclax

Introduction: Hypomethylating agents (HMA) with Venetoclax (Ven) is the standard of care for patients with acute myeloid leukemia (AML) ≥ 75 yrs of age or not candidates to intensive treatment. Döhner, et al. (ASH 2022) demonstrated that the European LeukemiaNet (ELN) risk classifications do not accurately predict prognosis in HMA-Ven treated patients. A prognostic risk signature classification (PRSc) was proposed, stratifying patients by RAS, FLT3 and TP53 mutations alone. We report a validation of this PRSc in a large cohort of patients treated with HMA-Ven. Methods: This unicentric analysis included patients older than 60 years old with newly diagnosed treated with HMA-Ven in different treatment protocols. Responses were assessed with the ELN-2022 criteria. The PRSc allocated patients with [ K/N]- RAS or FLT3-ITD mutations in the intermediate benefit group, patients with TP53 in the lower benefit group, whereas patients with AML lacking these mutations were allocated in the higher benefit group. Cumulative incidence (CI) was calculated for pts achieving remission with death and relapse as competing events. Results: A total of 179 patients were included, diagnosed between 11/2014 and 12/2021. Median age was 74 yrs old (range, 61-89) and 58% were male. 31% of patients had diploid cytogenetics and 35% had complex karyotype. According to the ELN 2022 risk category, 30 (17%), 15 (8%) and 114 (64%) patients were allocated in the favorable, intermediate and adverse risk group, respectively. According to the PRSc, 75 (42%), 31 (17%) and 54 (30%) were allocated in the higher, intermediate and lower benefit group, respectively. In the PRSc intermediate benefit group, 21 patients had NRAS mutations, 9 patients had KRAS mutation and 7 patients had FLT3-ITD. Patients received treatment with decitabine 10 days with Ven (n=89, 50%), decitabine 5 days with Ven (n=69, 38%), oral decitabine 5 days with Ven (n=14, 8%) and Azacitidine 7 days with Ven (n=7, 4%). The overall response rate (ORR) was 70% (126/179), including 96 pts (54%) achieving complete remission (CR) rate and 30 (17%) having CR with incomplete hematologic recovery (CRi). The ORR for patients allocated in the ELN 2022 favorable, intermediate and adverse risk was 90% (27/30), 93% (14/15) and 63% (72/114). According to the PRSc, the ORR was 87% (65/75), 55% (17/31) and 59% (32/54) for patients of the higher, intermediate and lower benefit group, respectively. The median number of cycles to best response was 1 (1-8), and 22 patients (12%) underwent allogeneic stem cell transplantation. After a median follow-up of 35 months, the median overall survival (OS) was 11 months. According to the ELN 2022 classification, the mOS was 44, 13 and 8 months (p<0.001, C-index=0.6). When applying the PRSc, the median OS was 30, 12 and 5 months for higher, intermediate and lower benefit group (p<0.001, C-index=0.66). Median event-free survival (EFS) was 8 months, being 30, 8, and 5 months for ELN 2022 favorable, intermediate and adverse group, respectively (p<0.001, C-index=0.62). When applying the PRSc, the median EFS was 18, 8 and 4 months for higher, intermediate and lower benefit group, respectively (p<0.001, C-index=0.65). The 2-yr CI of relapse and death was 47% and 22%, respectively. By the ELN 2022 subgroups, the 2-yr CI of relapse was 29%, 43% and 55% for favorable, intermediate and adverse groups, respectively (p=0.1). The 2-yr CI of death was 12%, 21% and 25% for favorable, intermediate and adverse groups, respectively (p=0.4). By the PRSc, the 2-yr CI of relapse was 26%, 70% and 60% for higher, intermediate and lower benefit group, respectively (p=0.004). The 2-yr CI of death was 20%, 6% and 33% for higher, intermediate and lower benefit group, respectively (p=0.1). Conclusion: The PRSc classification can stratify 3 different groups of patients with distinct outcomes. In the present study the 3 categories defined by the PRSc have very similar survival than the median OS previously reported (27, 12 and 5 months for higher, intermediate and lower benefit group), with a better performance according to the C-index. Signaling mutations ( RAS or FLT3-ITD) as well as TP53 mutations represent a challenge with HMA-Ven, in which novel treatments or combinations are warranted to improve outcomes.

Integrative Multi-Omic Analysis for Prognosis Stratification in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a heterogeneous hematopoietic malignancy with a dismal prognosis. European LeukemiaNet (ELN) is crucial for tailoring AML treatment individually. Various AML models correlated survival and clinical drug response with immune cell differentiation state by deconvoluting transcriptomics. However, few comprehensive molecular subtyping models integrate multi-omic profiles for prognostic and drug response prediction. Thus, this study aimed to integrate DNA methylation, genomics, transcriptomics and ex vivo drug sensitivity screening of AML patients and explore their roles in facilitating AML molecular stratification and redefining prognosis. Firstly，data on 90 patients with AML(non-promyelocytic leukemia) were retrieved from The Cancer Genome Atlas (TCGA) for consensus clustering by 10 advanced consensus clustering algorithms. The optimal three distinct subtypes, UAMOCS1, UAMOCS2, and UAMCOS3, were identified to achieve the best clustering effect. Multi-omics were orchestrated together for UAMOCS shaping. The UAMOCS can significantly distinguish overall survival (median 18 vs. 27 vs. 45 months, P= 0.0048) among the three instinct subtypes with the integrated contribution of transcriptomic profiles and DNA methylation and mutation data. Also, the activity of AML-specific transcription factors and chromatin remodeling makers showed a diverse pattern among the three subtypes, epigenetically contributing to UAMOCS shaping. Next, the nearest template prediction, a model-free method, was applied to further validate this predictive model. Similar subtyping under this model is generated robustly by imitating 50 subtype-specific genes and capable of identifying survival in both the “ihCAMs-AML” (Figure 1) and GSE37642. The main validation cohort was a real-world de novo AML cohort (acute promyelocytic leukemia excluded), “ihCAMs-AML”（N=98）, aged 14-70 years, with a median follow-up of 28 (1-55) months. The samples were simultaneously available for methylome (N=31, 850K Methylation Chip), DNA mutation (N=96, targeted deep sequencing), transcriptome (N=98, bulk RNA-seq), and ex vivo drug screening (N=66, 17 drugs under 100% peak plasma concentration) profiling analysis. Clinical relevance showed that traditional cytogenetic stratification was strongly correlated with our system. UAMOCS1, acting as an “immune activator”, is characterized by enriching of AML myelodysplasia-related (AML-MR) gene mutations (especially RUNX1 mutation, P = 0.00839), unstable chromosome (deletions on 7q), increased abundance of immune cells with immune escaping marker and poor risk. UAMOCS2 was defined as an intermediate immune burden and a “monocytic-like” phenotype with intermediate survival, corresponding to its inclining result toward M4/M5. UAMOCS3 was an “immune desert” group supposed to be the most favorable subset among the three groups. The ex vivo drug screening result implied that UAMOCS also provide values in distinguishing drug response. UAMOCS1 hardly benefited from commonly used chemotherapeutic drugs compared with the other two distinct subtypes. Pharmacogenomics database GDSC (the Genomics of Drug Sensitivity in Cancer) among AML cell lines was used to evaluate potential drug targets for overcoming drug resistance. Receptor tyrosine kinase signaling inhibitors (SB505124 and EphB4) might be sensitive to UAMOCS1. Taken together, UAMOCS model was generated that can classify AML patients independently and help develop precise chemotherapeutic strategy for patients with AML in the future.

Safety and Efficacy of Azacitidine and Chidamide Maintenance after Allogeneic Hematopoietic Stem Cell Transplantation for Patients with High-Risk Acute Myeloid Leukemia: Interim Analysis of a Prospective, Multicenter, Single-Arm, Phase Ⅱ Clinical Trial

Background Although allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the potentially curative therapy for AML, the relapse rate after HSCT is high with 30-60% for patients with high-risk AML. Maintenance therapy with efficacy and low toxicity is needed to mitigate relapse. It has been reported that histone deacetylases inhibitor chidamide exhibits anti-tumor activity against AML cells, and is able to elicit anti-tumor immune response in mouse models. However, efficacy and safety of chidamide as maintenance therapy following allo-HSCT for patients with AML have not been reported. Therefore, we designed a multicenter, single arm, phase II clinical trial for high-risk AML patients to use azacitidine combined with chidamide as maintenance therapy post allo-HSCT to prevent relapse. Methods In this multicenter, single arm, phase II clinical trial, patients aged 18-60 years with high-risk AML, defined as the European LeukemiaNet (ELN) 2017 adverse risk group, refractory, relapsed or secondary AML were given AZA and chidamide as maintenance therapy after 60 days post transplantation (NCT05270200). AZA was given at 100mg/day (days 1-5) for 6 cycles and chidamide 5mg daily (days 1-28) with a cycle of 28 days for up to 2 years. The dose of AZA was amended at 50mg/m 2/day (days 1-3) from Dec 23,2022 due to occurrence of thrombocytopenia. If PLT was below 50×10 9/L or grade 3/4 non-hematological toxicity occurs, maintenance should be interrupted or delayed until PLT count was greater than 75×10 9/L or the non-hematological toxicity resolved to ≦ grade 1. Primary objectives were safety and one year cumulative incidence of relapse. Secondary objections were relapse-free survival (RFS), overall survival (OS) and incidence of severity of acute and chronic graft-versus-host disease (GVHD). Results From February 12,2022 to June 30,2023, seven patients were enrolled, with a median age of 46 years（28-60), four patients (57%) were female. One patient (14%) received matched sibling donor transplantation, six patients (86%) received haploidentical donor transplantation. Five patients (71%) received myeloablative and 2/7 (29%) reduced intensity conditioning regimen. Six (86%) were in ELN 2017 adverse risk with three patients harboring KMT2A rearrangement, one patient with TP53 mutation, one patient with -7, one patient with RUNX1 mutation, while one patient (14%) was diagnosed as secondary AML with broad extramedullary infiltration. All but one patients entered transplant in CR, while five patients (83%) were MRD negative and one patient (17%) were positive. The baseline patient characteristics are summarized in Table1. Outcome data were updated as of June 30,2023 (Figure1). The median time to start maintenance therapy after transplantation was 77 days (range 64-80). The median follow-up time was 9.9 months, only one patient relapsed and the accumulative incidence of relapse of one year was 16.7%（95%CI,0.4%-64.1%). The relapsed patient diagnosed with MLL-AF10 rearrangement had extramedullary infiltration of left tonsil, gum and neck lymph nodes at 197 days post transplantation while bone marrow remained in MRD negative remission. AZA/chidamide were well tolerated, with no severe adverse event was recorded. Two grade 3/4 non-hematologic adverse events were observed, with one increased bilirubin due to cGVHD and one pneumonia. Two patients (29%) experienced grade4 thrombocytopenia requiring platelet transfusion. After amendment of AZA dose, no grade4 thrombocytopenia was recorded. No one discontinued treatment due to toxicity. During follow-up, none of patients had aGVHD. Three patients (43%) experienced mild or moderate cGVHD, no severe cGVHD was observed. The median OS was not reached, with six months and one year OS both of 100%. The median RFS is not reached, with six months and one year RFS of 100% and 83.3%(95%CI,35.9%-99.6%). Conclusions Preliminary results suggest that maintenance of AZA combined with chidamide post allo-HSCT in patients with high-risk AML exhibits promising efficacy and well-tolerated. Recruitment of patients with high-risk AML post allo-HSCT for this trial is ongoing. Disclosures No relevant conflicts of interest to declare.

Comparative Analysis of Clinical Outcomes and Healthcare Resource Utilization (HRU) in Patients (Pts) with Newly Diagnosed (ND) Acute Myeloid Leukemia (AML) Unfit for High-Intensity Chemotherapy Treated with Venetoclax (VEN) Vs Other Therapies: Results from the AML Real World Evidence (ARC) Initiative

Introduction: The BCL-2 inhibitor VEN is approved in combination with hypomethylating agents or low-dose cytarabine for adults with ND AML. The ARC Initiative is a multicenter chart review study of adult pts with AML. This abstract presents real-world clinical outcomes and hospitalizations among ND AML VEN treated pts ineligible for intensive chemotherapy (IC) and their matched controls. Methods: This multicenter chart review study included adult pts (≥18 years) with ND AML who received VEN in combination with HMA on or after April 2016, or non-VEN regimens on or after May 2015, from 15 international academic sites (US: 11; Israel: 4). Pts ineligible for IC (i.e., ≥75 years or ≥1 comorbidity based on the Ferrara criteria) and treated with VEN (VEN cohort) were matched 1:1 to control pts who received non-VEN-based regimens (CON cohort). Pts were matched based on age (<60, 60-74, ≥75 years) and European LeukemiaNet (ELN 2017) risk. All analyses are based on the May 2023 data cutoff; data collection is ongoing. Clinical outcomes include composite complete remission (CRc; i.e., CR, CR with partial hematologic recovery [CRh], or CR with incomplete marrow recovery [CRi]) and overall survival (OS; assessed using Kaplan-Meier analysis). Hospitalizations were assessed overall and among pts who achieved CRc. Results were separately reported overall and among the respective subsets of VEN pts matched to CON pts treated with high-intensity regimens (CON-H) or low-intensity regimens (CON-L). Results: A total of 142 IC-ineligible VEN pts and 142 matched CON pts were included in the analysis, including 80 VEN pts matched to CON-H pts (56.3%) and 62 VEN pts matched to CON-L pts (43.7%) ( Table 1). Overall, VEN pts received VEN-azacitidine (75.4%) or VEN-decitabine (24.6%). A total of 68.3% of all pts were classified as ELN adverse risk, and 24.6% of VEN pts and 20.4% of CON pts were classified as Eastern Cooperative Oncology Group (ECOG) Grade ³2. Among pts with genetic mutations tested (96.5% of VEN pts and 94.4% of CON pts), 22.6% of VEN pts and 14.2% of CON pts had TP53 mutations and 21.9% and 19.4%, respectively, had IDH1/2 mutations. VEN pts had a mean of 11.6 months of follow-up, and CON pts had a mean of 15.0 months of follow-up. VEN pts were significantly more likely to achieve CRc than CON pts (64.7% vs 44.3%, p=0.001). This difference was more pronounced for VEN pts matched to CON-L pts (62.1% vs 18.0%, p<0.001). The 6-month OS rates were not statistically different between VEN pts and matched CON pts (74.7% vs 67.6%; p=0.20), despite the majority of CON pts receiving high-intensity regimens, but improved among VEN pts matched to CON-L pts (73.5% vs 55.3%; p<0.05). VEN pts had fewer days of hospitalization per pt per month (PPPM; mean 6.3 days vs 8.9 days, p=0.045) and shorter mean duration of hospitalization (13.7 days vs 18.2 days, p<0.001) compared with CON pts. A larger difference was seen in the amount of time (days) (6.5 vs 10.5 PPPM, p=0.006) and mean length of hospital stay (13.9 vs 22.4 days, p<0.001) for VEN pts matched to CON-H pts. Among pts with ≥1 all-cause hospitalization, 69.2% of VEN pts and 74.8% of CON pts were hospitalized for treatment administration (p=0.42). Among pts who achieved CRc, VEN pts had fewer days of hospitalization PPPM than CON pts (mean 4.3 days vs 6.8 days, p=0.002). This difference was more pronounced for VEN pts compared to CON-H pts (4.3 days vs 7.7 days, p=0.001). Mean duration of hospitalization was also shorter for VEN vs CON pts (13.6 days vs 20.4 days, p<0.001). Both VEN and CON pts experienced more hospitalizations before CRc was achieved, with statistically fewer hospitalizations for VEN pts compared with CON pts (days of hospitalization PPPM: 10.1 vs 17.4, p=0.001; duration of hospitalization: 16.4 vs 28.2, p<0.001). In the 60 days after CRc was achieved, VEN pts still had fewer days of hospitalization PPPM than CON pts (1.4 vs 5.2, p<0.001). Conclusions: Pts with ND AML who were ineligible for IC and received VEN had significantly higher rates of CRc than matched pts who received non-VEN-based regimens. Although pts treated with VEN-based regimens achieved similar rates of CRc compared to matched control pts treated with high-intensity therapy, pts treated with VEN-based regimens required a significantly lower burden of hospitalizations compared with matched pts on non-VEN-based regimens.

MP0533, a CD3-Engaging Darpin Targeting CD33, CD123, and CD70 in Patients with Relapsed/Refractory AML or MDS/AML: Preliminary Results of a Phase 1/2a Study

BACKGROUND: The development of targeted immunotherapy for acute myeloid leukemia (AML) is challenging due to the clonal heterogeneity of the disease and the lack of single AML-specific target antigens. MP0533 is a multi-specific, half-life extended CD3-engaging DARPin (Designed Ankyrin Repeat Protein). It simultaneously targets CD33, CD123, and CD70, thereby enabling avidity-driven T cell-mediated killing of leukemic stem cells (LSCs) and malignant blast cells known to co-express these targets. MP0533's affinity to each target is tuned to preferentially kill malignant cells which co-express at least two of these three antigens, while preserving a therapeutic window towards healthy cells. MP0533 was shown to induce a tumor-specific endogenous T-cell response in ex vivo samples from AML patients and led to T-cell-mediated eradication of tumors in AML xenograft mouse models, with limited cytokine release or other serious adverse reactions (Bianchi et al., Blood 2022;140[Suppl 1]:2251-2). Herein, we present early observations of the first three MP0533 dose-escalation regimens (DR) of the ongoing first-in-human, multicenter, single-arm, open-label, phase 1/2a study. METHODS: The objectives of this ongoing trial are to evaluate the safety/tolerability, pharmacokinetics (PK), and pharmacodynamics, as well as preliminary antileukemic activity of MP0533 monotherapy in patients with relapsed/refractory (R/R) AML or myelodysplastic syndrome (MDS)/AML (NCT05673057). Patients with an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2, and a life expectancy of ≥12 weeks are eligible. Up to 45 patients will be enrolled in the dose-escalation part of the trial. Patients receive MP0533 once per week starting at day 15 after a stepwise dose increase on days 1, 5, and 8, and until disease progression or unacceptable toxicity. One cycle corresponds to 28 days. DR escalation of MP0533 is guided by two Bayesian logistic regression models estimating the joint probability of cytokine release syndrome (CRS) and non-CRS dose-limiting toxicities (DLTs). Bone marrow examinations are performed at weeks 4, 8, and 12. Responses are determined using 2022 European LeukemiaNet (ELN) criteria with an assessment of hematologic improvement. Treatment-emergent adverse events (TEAEs) are assessed according to National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) v5.0. RESULTS: As of data cut-off (20 July 2023), 5 patients received ≥5 infusions of MP0533 across 3 DRs preceded by step-up dosing (1 patient each at DR 1 and DR 2, respectively, and 3 patients at DR 3), including 2 women and 3 men. The median age at enrollment was 79 years (range 68-81). All patients had adverse risk mutations. Patients received a median number of 1 prior antileukemic therapy line (range 1-2) and on average 2 cycles of MP0533 treatment (range 1-3). To date, one patient with a TP53 mutation achieved a morphologic leukemia-free state after 8 weeks and complete remission with incomplete hematologic recovery (CRi) after 12 weeks of treatment with DR 3. No DLTs have been observed in any DR so far. TEAEs considered to be related to MP0533 were Grade 2 infusion-related reaction (2 patients), Grade 1 CRS (2 patients), and Grade 1 diarrhea and fatigue (1 patient). No Grade ≥3 drug-related TEAEs were reported. The reported TEAEs (Figure) reflected the patients' disease course. Preliminary PK results up to DR 3 confirmed that all patients were exposed to MP0533 and exposure levels were broadly aligned with PK/PD model predictions of MP0533 in serum. CONCLUSION: The results of this ongoing phase 1/2a study indicated an acceptable safety profile of MP0533 monotherapy in 5 patients up to DR 3 with weekly infusions. Preliminary response data are encouraging, with one response observed in 1 of 2 patients evaluable for response in DR 3 to date.

Identification of Multivariable microRNA and Clinical Biomarkers Panels to Predict Imatinib Response in Chronic Myeloid Leukemia at Diagnosis

Imatinib Mesylate (IM) was once hailed as the magic bullet for chronic myeloid leukemia (CML) and remains a front-line therapy for CML to this day alongside other tyrosine kinase inhibitors (TKIs). However, TKI treatments are rarely curative and while they demonstrate efficacy in managing the disease, patients are often required to receive life-long treatment or risk experiencing relapse. Patients also frequently harbor innate TKI-resistance mechanisms to front-line IM therapy and without prior screening, patients can spend precious months on non-optimal treatment before transitioning to other therapeutic strategies. Thus, there is a growing interest in studying biomarkers in patients which can predict TKI response upon diagnosis. CML has unique microRNA (miRNA) expression profiles at different stages of the disease and in response to TKI-treatment. We previously generated global transcriptome profiles on treatment-naïve CD34 + CML cells with known subsequent imatinib (IM) responses and identified several differentially expressed miRNAs in IM-nonresponders as compared to IM-responders. We also reported that IM response could be predicted in treatment-naïve CD34 + cells by an in vitro colony forming cell (CFC) assay. Additionally, we previously analyzed patient data from the ENESTxtnd clinical trial to show that miRNA expression combined with CFC output data could accurately predict Nilotinib response in patients. In this study, we used a Cox Proportional Hazard (CoxPH) analysis to identify 22 out of a pool of 35 pre-validated miRNAs which were associated with IM nonresponse in CD34 + CML cells of 80 patients at diagnosis. These patients were later classified as IM-responders or IM-nonresponders based on the latest European LeukemiaNet (ELN) guidelines. Interestingly, a Welch t-test revealed 16 of these 22 IM-response associated miRNAs to be differentially expressed between IM-responders and IM-nonresponders. Between IM-responders and IM-nonresponders we also found 7 clinical parameters that were associated with IM-response of which 3 matched parameters had significantly different values including CFC assay outputs ( p=0.0015), Sokal scores ( p=0.0070) and white blood cell counts (WBC, p=0.0028). We then trained a machine learning model employing the random-forest (RF), gradient-boosting (GBM) and naïve-bayes (NB) algorithms with different combinations of the 16 miRNAs with and without the clinical parameters of these patients to identify panels with high predictive performance based on area-under-curve (AUC) values of receiver-operating-characteristic (ROC) and precision-recall (PR) curves. Notably, the multivariable panel consisting of both miRNAs and clinical features (AUC-ROC RF=0.83, GBM=0.83, NB=0.84, AUC-PR RF=0.68, GBM=0.67, NB=0.70) performed better than either miRNA (AUC-ROC RF=0.72, GBM=0.73, NB=0.78, AUC-PR RF=0.49, GBM=0.51, NB=0.4) or clinical (AUC-ROC RF=0.82, GBM=0.84, NB=0.84, AUC-PR RF=0.64, GBM=0.67, NB=0.64) panels alone. Interestingly, 2 miRNAs in this panel, miR-185 and miR-145, were also significant classifiers for our Nilotinib predictive study suggesting that expression patterns of these miRNAs may have predictive properties for multiple TKI responses. Thus, we show that predictive accuracy of biomarkers may be supplemented by inclusion of multivariable parameters, and our findings may inform future studies on developing predictive panels for more optimized treatment plans in the clinic.

Assessment of SIRT1-SIRT7 and TP53 Genes Expression in Patients with Acute Myeloid Leukemia

BACKGROUND Sirtuins ( SIRTs) are a family of histone deacetylases with 7 representatives ( SIRT1-7), which affect cell survival and metabolism. They influence gene expression by interacting with histones and transcription factors, or directly modulate pathways associated with cell survival, for instance by downregulating p53, thus potentially contributing to cancerogenesis. On the other hand, SIRTs may function as tumor suppressors depending on cellular context. While the role of SIRTs expression is widely discussed in solid neoplasms, they have not been comprehensively evaluated in acute myeloid leukemia (AML) yet. AIMS To investigate the prognostic importance of initial SIRTs expression in AML patients (pts) and its relationship with the expression of TP53. METHODS The study included 40 newly diagnosed AML pts (19 women, 21 men), with a mean age of 62 years (range: 26-87). Low-, intermediate- or high-risk AML according to European LeukemiaNet (ELN) 2022 stratification was diagnosed in 6 (15%), 13 (32.5%), and 21 (52.5%) of pts respectively. The expression of SIRT1-7 and TP53 was examined by real-time PCR using the TaqMan chemistry and the QuantStudio7 thermal cycler (Applied Biosystems-Thermo Fisher Scientific). The reference genes were selected using GeNorm and NormFinder. The mRNA levels were normalized by the formula ∆Ct = Ct(reference) - Ct(particular mRNA). Group comparisons were performed using Welch's t-test. Pearson correlation evaluated the relationship between individual gene expression. Overall survival (OS) was assessed by the Kaplan-Meier method with the log-rank test. Cox proportional hazard regression of clinical factors and genes expression for predicting OS was performed. RESULTS FLT3 ITDor TKD mutations were present in 10 (25%) of pts, NPM1 in 9 (23%), and IDH1 or IDH2 in 6 (15%). 14 (35%) of the study group were diagnosed with AML with myelodysplasia-related cytogenetic abnormalities, AML progressed from myelodysplastic syndrome, or therapy-related AML (secondary AML, sAML). Standard induction chemotherapy was given in 42.5% of pts, 25% were treated with azacitidine+venetoclax (Aza+Ven), and other non-intensive therapies were administered to 32.5%. SIRT4 expression was detected in 92.5% of pts, while expression of the other genes studied was found in all pts. There were no differences in SIRT 1-7 expression in terms of ELN2022 risk stratification. However, TP53 was downregulated in the high-risk group (fold change - FC=0.6, p=0.004). In pts with FLT3 mutation, SIRT7 was downregulated (FC=0.8, p=0.07), while in both NPM1 and IDH1/2 mutated groups, we showed upregulation of TP53 (FC=1.5, p=0.03, and FC=1.5, p=0.001, respectively). Moreover, in older pts (>60 years old) TP53 was downregulated (FC=0.7, p=0.02). In sAML group SIRT3 and TP53 were downregulated (FC=0.7, p=0.08, and FC=0.7, p=0.05, respectively). Significant positive correlations were shown between the expression of individual SIRTs, and it was most strongly expressed between SIRT2 and SIRT6 (r=0.85, p=0.00), SIRT2 and SIRT7 (r=0.81, p=0.00), and SIRT6 and SIRT7 (r=0.76, p=0.00). The median follow-up was 6.7 months (95% CI: 4.5-9.1). The median OS in the study cohort was not reached. There were no significant differences in treatment response or OS considering each SIRT expression level. However, pts with higher TP53 expression (> median) presented longer OS (median OS not reached vs 5.8 months (95% CI:1.3-5.8, p=0.05) [Figure 1]. In the multivariate Cox proportional hazard model for OS, upregulation of TP53 (HR 0.25, 95%CI: 0.08-0.60, p=0.01), age (HR 1.06, 95%CI: 1.01-1.12, p=0.03), as well as initial albumins (HR 0.01, 95%CI: 0.00-0.07, p=0.01), and LDH levels (HR 1.00, 95%CI: 1.00-1.01, p=0.01) were factors influencing the outcome [Table 1]. CONCLUSIONS The expression of SIRTs in AML presented no evident impact on treatment outcome. However, our study revealed that higher TP53 expression was associated with longer OS. Moreover, TP53 upregulation was found in pts with certain mutational profiles, while downregulation in the elderly and those with sAML. The analysis indicates that SIRTs expression may also vary markedly depending on the clinical and molecular context. The expression of individual SIRTs is closely correlated with each other, but these preliminary results did not show their direct relationship with TP53 expression. Further studies on SIRTs are needed to assess their impact on AML.