European LeukemiaNet Criteria Research Articles

Effective Management of Polycythemia Vera With Ropeginterferon Alfa-2b Treatment.

Polycythemia vera (PV) is a myeloproliferative neoplasm. Ropeginterferon alfa-2b is a new-generation polyethylene glycol-conjugated proline-interferon. It is approved for the treatment of PV at a starting dose of 100 µg (50 µg for patients receiving hydroxyurea (HU)) and dose titrations up to 500 µg by 50 µg increments. The study was aimed at assessing its efficacy and safety at a higher starting dose and simpler intra-patient dose escalation. Forty-nine patients with PV having HU intolerance from major hospitals in China were treated biweekly with an initial dose of 250 µg, followed by 350 µg and 500 µg thereafter if tolerated. Complete hematological response (CHR) was assessed every 12 weeks based on the European LeukemiaNet criteria. The primary endpoint was the CHR rate at week 24. The secondary endpoints included CHR rates at weeks 12, 36 and 52, changes of JAK2V617F allelic burden, time to first CHR, and safety assessments. The CHR rates were 61.2%, 69.4% and 71.4% at weeks 24, 36, and 52, respectively. Mean allele burden of the driver mutation JAK2V617F declined from 58.5% at baseline to 30.1% at 52 weeks. Both CHR and JAK2V617F allele burden reduction showed consistent increases over the 52 weeks of the treatment. Twenty-nine patients (63.0%) achieved partial molecular response (PMR) and two achieved complete molecular response (CMR). The time to CHR was rapid and median time was 5.6 months according to central lab results. The CHRs were durable and median CHR duration time was not reached at week 52. Mean spleen index reduced from 55.6 cm2 at baseline to 50.2 cm2 at week 52. Adverse events (AEs) were mostly mild or moderate. Most common AEs were reversible alanine aminotransferase and aspartate aminotransferase increases, which were not associated with significant elevations in bilirubin levels or jaundice. There were no grade 4 or 5 AEs. Grade 3 AEs were reversible and manageable. Only one AE led to discontinuation. No incidence of thromboembolic events was observed. The 250-350-500 µg dosing regimen was well tolerated and effectively induced CHR and MR and managed spleen size increase. Our findings demonstrate that ropeginterferon alfa-2b at this dosing regimen can provide an effective management of PV and support using this dosing regimen as a treatment option.

Impact of MDR-1 Gene Polymorphism (rs1128503) on Response to Imatinib or Nilotinib in Iraqi Patients with Chronic Myeloid Leukemia: An Observational Study

Background: There is a significant molecular response to imatinib given at standard doses in individuals with chronic myeloid leukemia (CML) whose ABCB1 polymorphisms are present. Objective: To investigate the impact of the polymorphism in the ABCB1 gene rs1128503 on the effectiveness of nilotinib or imatinib therapy. Methods: From May 2022 until the end of January 2023, the current study was carried out in a single research institution, the National Center of Hematology, Baghdad Teaching Hospital at Medical City, Iraq. 76 people with chronic phase myeloid leukemia (CML-CP), who had previously received a diagnosis using the European Leukemia Net (ELN) criteria, enrolled in the trial. The PCR product was delivered to Macrogen Corporation, Korea, for Sanger sequencing on an automated DNA sequencer, the ABI3730XL. After receiving the results by email, Geneious Prime software was used for analysis. Results: Patients receiving imatinib or nilotinib did not differ significantly in terms of age or gender. In contrast, BCR-ABL1 transcript levels were considerably greater at sampling in patients receiving nilotinib. Different types of the MDR-1 gene rs1128503 genotype were not found in groups that were treated with either imatinib or nilotinib. Conclusions: BCR-ABL1 transcript levels are lower in patients still receiving imatinib than in those receiving nilotinib.

ROP-ET: a prospective phase III trial investigating the efficacy and safety of ropeginterferon alfa-2b in essential thrombocythemia patients with limited treatment options

Interferon-based therapies, such as ropeginterferon alfa-2b have emerged as promising disease-modifying agents for myeloproliferative neoplasms (MPNs), including essential thrombocythemia (ET). Current ET treatments aim to normalize hematological parameters and reduce the thrombotic risk, but they do not modify the natural history of the disease and hence, have no impact on disease progression. Ropeginterferon alfa-2b (trade name BESREMi®), a novel, monopegylated interferon alfa-2b with an extended administration interval, has demonstrated a robust and sustained efficacy in polycythemia vera (PV) patients. Given the similarities in disease pathophysiology and treatment goals, ropeginterferon alfa-2b holds promise as a treatment option for ET. The ROP-ET trial is a prospective, multicenter, single-arm phase III study that includes patients with ET who are intolerant or resistant to, and/or are ineligible for current therapies, such as hydroxyurea (HU), anagrelide (ANA), busulfan (BUS) and pipobroman, leaving these patients with limited treatment options. The primary endpoint is a composite response of hematologic parameters and disease-related symptoms, according to modified European LeukemiaNet (ELN) criteria. Secondary endpoints include improvements in symptoms and quality of life, molecular response and the safety profile of ropeginterferon alfa-2b. Over a 3-year period the trial assesses longer term outcomes, particularly the effects on allele burden and clinical outcomes, such as disease-related symptoms, vascular events and disease progression. No prospective clinical trial data exist for ropeginterferon alfa-2b in the planned ET study population and this study will provide new findings that may contribute to advancing the treatment landscape for ET patients with limited alternatives.Trial registrationEU Clinical Trials Register; EudraCT, 2023-505160-12-00; Registered on October 30, 2023.

Treatment outcome of the tyrosine kinase inhibitor (bosutinib) in previously treated chronic myeloid leukemia patients (sample of Iraqi patients)

Abstract: BACKGROUND: Chronic myeloid leukemia (CML) is a type of myeloproliferative neoplasm characterized by the excessive accumulation of malignant myeloid cells in the bone marrow and peripheral blood. This condition is primarily triggered by a specific chromosomal translocation known as t(9;22) (q34.13;q11.23), which leads to the formation of the BCR-ABL fusion gene. The treatment landscape for CML has undergone significant changes with the approval of tyrosine kinase inhibitors (TKIs) targeting the BCR-ABL1 kinase activity. One such inhibitor is bosutinib, which has been available for several years to treat patients with chronic, accelerated, and blast-phase CML who have shown resistance or intolerance to previous therapies. OBJECTIVES: The aim of this study was to assess efficacy and safety of Bosutinib as a 2nd line therapy in CML patients, in addition to effect of adherence to treatment on patients response. PATIENTS AND METHODS: Eighty-five patients with CML were enrolled in a prospective cohort study from October 2021 to October 2022 at Hematology Center in Medical City Complex – Baghdad. All patients failed to at least one TKI, and all of them started escalated dose of bosutinib. The patients were followed-up by assessing molecular and cytogenetic response at 3 and 6 months and monitored carefully for adverse events (AEs) which were graded by common terminology IX criteria for AEs version 5. Adherence to bosutinib was also monitored by a specific adherence scale to optimize the response rate to treatment. RESULTS: The mean age of patients was 47.3 ± 14.9 (range: 18–77), with male:female ratio 1.4:1. Status of CML patients showed that 89.4% were in the chronic phase, 5.8% in accelerated phase, and 4.7% in blast phase. Regarding the number of previous TKIs before bosutinib, 72.9% of patients failed to prior one TKI (imatinib). At 6 months (72.3%), patients achieve optimal response according to European Leukemia Net criteria 2013. Gastrointestinal symptoms and dermatological manifestations were the most common nonhematological AEs of bosutinib. According to 9-item Morisky Medication Adherence Scale, 42% of patients were adherent to medication which showed a significant association with a higher number of optimal response (P = 0.0001). CONCLUSION: Bosutinib is effective with a high and promising response as a subsequent line treatment in CML patients, and it is generally safe and associated with mild-to-moderate tolerable and manageable AEs. Adherence to the drug plays a significant role in optimal response to bosutinib.

Harnessing Artificial Intelligence for Risk Stratification in Acute Myeloid Leukemia (AML): Evaluating the Utility of Longitudinal Electronic Health Record (EHR) Data Via Graph Neural Networks

Background: AML is a life-threatening disease, and to determine which patients need allogeneic stem cell transplantation, hematologists risk-stratify each case. However, standard risk stratification using the European LeukemiaNet (ELN) criteria is focused on baseline mutations and chromosomal aberrations, and the risk estimate is not updated during a patient's course. In other blood cancers, recalculating the risk with treatment response data can help guide the need for more intensive therapy (Kurtz, et al, Cell, 2019). Furthermore, deep learning graph neural networks (GNN) applied to EHR data have strong predictive power in a hematology context (Fouladvand, et al, J Biomed Inform, 2023). Thus, we evaluated the power of a GNN to predict survival in AML using longitudinal EHR data, specifically with labs and histological features that are not included in the ELN but may capture the treatment response. Methods: Patients who were seen at the Stanford Cancer Institute, had EHR data available within six months of diagnosis, and were diagnosed with AML between June 1998 and January 2021 were included in this retrospective analysis. The GNN was trained to predict survival at two years from diagnosis using the first six months of clinical data. Patients were excluded if they were lost to follow-up before two years or died before six months. Data were collected from structured databases associated with Stanford's EHR, except that diagnosis dates were from Stanford's Cancer Registry, and survival data was supplemented with other databases including the Social Security Death Index. Dysplasia, bone marrow cellularity, and bone marrow blast percentages from pathology reports (“pathology report data”) were extracted using text processing algorithms and weakly supervised machine learning (Ratner, et al, ArXiv, 2017). To represent time series information, we framed each patient's timeline as a network (or “graph”) of events. The primary GNN model was a heterogenous graph transformer classifier with two node types: complete blood count (CBC) data and pathology report data (Hu, et al, ArXiv, 2020). Data from the same week were assumed to be from the same timeframe and connected with bidirectional edges. Data separated by longer time periods were connected with unidirectional edges of a separate edge type. The independent test dataset consisted of patients whose ELN 2022 classification was available, and to train the model, the remaining data were divided into train/validation splits of 0.9/0.1. Results: Of the 2,535 patients with survival data, 1,029 met inclusion criteria. Table 1 summarizes the data available in the EHR for each variable, and nearly all patients had CBC and pathology report data. The area under the receiver operating characteristic (AUROC) using the ELN 2022 criteria for predicting survival in the test dataset was 0.79. The AUROC curve for the GNN model was comparable at 0.76, despite not using any variables from the ELN criteria, and the model effectively stratified patients' disease into high- and low-risk in the independent test dataset (hazard ratio [HR] 3.0, log-rank p = 0.0009). Interestingly, despite not having access to mutation or cytogenetic data, the high-risk cases were enriched in known high-risk mutations, like TP53 and RUNX1, and in high-risk chromosomal aberrations, like 5q deletion (Table 1). Although the model predictions correlated with the ELN criteria in some ways, they also stratified the ELN intermediate-risk AML cases into high and low risk (HR 6.1 for model-predicted high risk among ELN intermediate cases, p = 0.07). Conclusions: Risk stratification using artificial intelligence and longitudinal data from the EHR performed comparably to the ELN 2022 criteria and has the potential to further stratify the ELN categories. The model performed well despite only using histological features and lab values, which are more readily available and more frequently updated than next-generation sequencing results. In the future, this approach may further improve with a larger sample size and additional variables, such as measurable residual disease and treatment information. Given the heterogeneity and increasing complexity of AML classification, leveraging artificial intelligence to assist with classification will be crucial, and these results are a step towards a future where data are automatically extracted from the EHR and used for continuously updated risk stratification.

Is the Eutos Long Term Survival (ELTS) Score a Useful Marker to Predict Outcome in Children with Newly Diagnosed Chronic Myeloid Leukemia (CML) in Chronic Phase (CP)? the Experience of the International Registry of Childhood CML

Aims. CML is a very rare disease in children. The present work aims to describe the characteristics of children with CML in chronic phase (CP) and to determine the outcome of this pediatric population. Methods. We retrospectively analyzed children with CML in CP registered in The International Registry of Childhood Chronic Myeloid Leukemia (I-CML-Ped Study; www.clinicaltrials.gov NCT01281735) which represents the largest cohort of children with CML. Results. Between January 2011 and March 2021, 576 CML patients less than 18 years of age at diagnosis were registered. We retrospectively selected 535 (92.8 %) children in CP according to the European leukemia net (ELN) criteria at diagnosis. Boys accounted for 58% of all patients with a boy to girl ratio of 1.25. The median age at diagnosis was 12.4 years (range, 8 months to 18 years). The most common symptoms at presentation were asthenia, weight loss and abdominal pain in 46%, 25% and 23% of the patients, respectively. CML in CP was diagnosed incidentally in 80 (16%) children when a blood assessment was performed for medical reasons. At diagnosis, thrombosis was observed in only one patient whilst 20% of the children presented with bleeding. Bleeding signs were associated with a higher frequency of palpable spleen (p=0.0007), higher leukocyte (p<0.0001) and platelets (p=0.02) counts, and a lower hemoglobin level (p=0.02). Clinical signs of leukostasis were observed in 88 (16.5%) patients. At diagnosis, spleen was palpable in 76% of the patients with a median of 9 cm (range, 1 to 32) below the costal margin. The median leukocyte count was 222 G/L (quartile 95-353). There is no statistical difference between boys and girls in terms of frequency of signs of leukostasis, frequency of splenomegaly, spleen size, median of the leucocyte count and hemoglobin level but the median of the platelet count was significantly higher in girls (p<0.0001). The majority (67%) of the children was allocated to the low-risk group according to the Eutos Long Term Survival (ELTS) score. First line therapy consisted of imatinib in 482 children with a median follow up of 4.6 years (IQR. 2.2-8.4). Among them, 208 (43%) children remained on imatinib with a median follow up of 2.9 years (IQR. 1.5-5.6). The main reason for switching (38.7% of the switches) was failure to achieve hematologic, cytogenetic or molecular response. Among the patients treated with imatinib first line, 15 (3.1%) children died and the probability of overall survival at 36 months was 97.4% (95% CI: 95-99%) (Figure 1). ELTS score was calculated for 406 of these patients: the 3-year survival rate was 98.1.% (95% CI: 96.3-100%), 94.4% (95% CI: 89.1-99.9%) and 95% (95% CI: 88.5-100%) in the low-, intermediate- and high-risk group, respectively (p logrank=0.009). Nineteen of these patients (3.9%) switched from imatinib to another treatment due to progression (accelerated or blastic phase). Progression free survival (PFS) rate at 3-years was 97.1% (95% CI: 94.9-99.2%), 91.7% (95% CI:84.5-98.3%) and 72.0% (95% CI: 59-87.9%) in the ELTS low-, intermediate- and high-risk group, respectively (p logrank<0.001) (Figure 2). Conclusion. The analysis of clinical and biological parameters of the largest cohort of children with CML in CP demonstrated that pediatric CML is characterized by a bulky disease (large splenomegaly, high leucocyte counts). However, these characteristics did not translate in a low rate of response and the outcome was similar to adults. While the ELTS score can identify children with the poorest outcome, a refined prognostic score specific for the pediatric population needs to be established and validated.

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.

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.

Impact of KMT2A-PTD Mutational Subgroups on Outcome of AML Patients after Induction Therapy and Allogeneic Hematopoietic Cell Transplantation

Introduction Genetic profiling of acute myeloid leukemia (AML) has increasingly revealed the possibility of adjusted therapeutic options. Recently, updates in genetic risk classifications introduced novel molecular features, but also excluded aberrations like partial tandem duplications in the lysine (K)-specific methyltransferase 2A ( KMT2A-PTD), formerly associated with adverse prognosis. Furthermore, there is growing evidence that molecular subtypes confer differential prognosis. Therefore, we analyzed a large cohort of AML pts to decipher the prognostic impact of KMT2A-PTD mutations ( KMT2A-PTD mut) including variants e9e3, e10e3 and e11e3 and their role in allogeneic hematopoietic cell transplantation (alloHCT). Methods Genomic DNA and total RNA of pts enrolled within the SAL registry (NCT03188874) was extracted at diagnosis. Samples were screened for KMT2A-PTD mut using the Mentype AMLplexQS Kit (Biotype, Dresden, Germany). Statistical as-treated analyses included standard statistical methods for categorial and continuous variables. Effects of alloHCT modeled as a time dependent covariate were estimated using Cox regression. Complete remission (CR) and survival rates were defined according to the current European Leukemia Net criteria. Logistic regression was used to evaluate CR rates and Cox regression to estimate hazard ratios (HR). The significance level was set at 0.05. All patients gave written informed consent. The study was conducted in accordance to the Declaration of Helsinki and was approved by the responsible ethics committees. Results Among 1409 pts, 206 pts harbored KMT2A-PTD mut, while 1203 pts showed wildtype (WT) alleles. KMT2A-PTD mut status was more often associated with secondary AML (p = .001) and less likely with concomitant NPM1 mutations (p < .001).Variants e9e3 (40.8%) and e10e3 (36.6%) were more frequently detected than e11e3 (22.6%). A total of 136 KMT2A-PTD mut and 859 WT pts received intensive induction therapy (IT). Rates of first complete remission (CR1) did not differ (p = .14). However, 5-year RFS was significantly lower in KMT2A-PTD mut pts compared to WT pts (15% vs. 25%), with median RFS of 23 vs. 29 months (HR = 1.4, p = .008). Accordingly, median OS was shorter (29 vs. 61 months; HR = 1.6, p = .002) and 5-year OS was lower for KMT2A-PTD mut pts compared to the WT counterparts (28% vs. 51%). In CR1, 81.6% of KMT2A-PTD mut pts proceeded to alloHCT and 18.4% of KMT2A-PTD mut pts received chemotherapy-based consolidation only. Median RFS improved from 15 to 37 months (HR = 0.5, p = .13) and chance of 5-year RFS enhanced from 17% to 21% when KMT2A-PTD mut pts underwent alloHCT in CR1 compared to KMT2A-PTD mut pts receiving chemo-consolidation.Median OS increased from 30 to 43 months when being allografted (HR = 0.5, p = .2), paralleled by increased rates of 5-year OS (33% chemo-consolidation vs. 47% alloHCT). Concerning KMT2A-PTD variants, there was no difference in likelihood to achieve CR1 between the three variants (p = .4). However, a trend towards shorter median OS ( e9e3: 41 months, e10e3:27 months, e11e3:27 months) and worse median RFS ( e9e3: 24 months, e10e3:23 months, e11e3:23 months) compared to WT pts (median OS: 61 months, median RFS: 29 months) could be revealed. Variant e10e3 was associated with worst prognosis (OS: HR = 2.1, p = .006; RFS: HR = 1.6, p = .06) and e9e3 with best prognosis (OS: HR = 1, p = .9; RFS: HR = 1.1, p = .7). e9e3 demonstrated best prognosis for both consolidation strategies. Median OS was not reached until last follow-up. Median RFS was higher in alloHCT pts (15 vs. 38 months, HR = 0.5, p = .3). e10e3 and e11e3 also had a higher median OS (12 vs. 43 months, HR = 0.3, p = .3 and 12 months vs. median survival not reached, HR = 0.2, p = .3, respectively) and RFS (11 vs. 41 months, HR = 0.3, p = .3 and 11 months vs. median survival not reached, HR = 0.2, p = .3, respectively) when allografted. Conclusions Based on our retrospective analysis, KMT2A-PTD mut are associated with reduced prognosis and survival in AML patients compared to WT pts. However, poor prognosis was effectively mitigated by alloHCT. Concerning KMT2A-PTD variants, we hypothesize alloHCT to be beneficial for improved survival. This effect seemed to be less pronounced for variant e9e3and more distinct for variant e11e3. Therefore, some KMT2A-PTD variants could be potentially implemented in AML risk stratification. However, prospective studies and larger patient numbers are needed.

Use of Geriatric Assessment and Genetic Profiling to Personalize Selection of Intensive Versus Low Intensity Chemotherapy in Older Adults with Acute Myeloid Leukemia (AML): Final Results of a Phase II Trial

Introduction: Geriatric assessment can predict the risk of toxicities of chemotherapy in older adults. Genetic risk categories are associated with survival following intensive chemotherapy in AML. Integrating geriatric assessment for patient profiling and genetic profiling of leukemic cells represents an innovative precision medicine approach to personalize therapy selection in older adults with AML. We report final results of a pragmatic phase II trial using such strategy, aiming to reduce early mortality (NCT03226418). Methods: Patients ≥60 years with a new diagnosis of AML underwent geriatric assessment prior to initiation of treatment. Geriatric assessment of physical function, cognitive function and comorbidity burden were used to determine fitness for intensive chemotherapy (Table 1). Additional assessment included Karnofsky Performance Scale (KPS), Patient Health Questionnaire-9 (PHQ-9), and Mini Nutritional Assessment-Short Form (MNA). Genetic profiling for therapy selection relied on karyotyping and followed the 2017 European LeukemiaNet criteria. While available mutation test results were incorporated to risk stratify, the study did not require waiting for the results prior to therapy initiation, given an anticipated turnaround time of 1-2 weeks for mutation test results. Therapy selection followed the algorithm in Figure 1. Patients with good or intermediate-risk AML received intensive chemotherapy such as 7+3 +/- gemtuzumab or midostaurin if determined to be fit. Patients with high-risk AML received low-intensity chemotherapy such as a hypomethylating agent with or without venetoclax or novel drugs (based on timing of FDA approval of these drugs), or CPX 351 if they were fit and met the FDA-approved indications. Patients with organ dysfunction (e.g. creatinine ≥2 mg/dl) and those requiring chemotherapy for other malignancy were eligible for low-intensity chemotherapy. Chemotherapy could be administered in community oncology settings. Patients were followed for quality of life assessments, as well as functional and oncologic outcomes. Results: Between July 2017-October 2022, 75 patients were consented; 2 patients were considered screen failure. Baseline characteristics of 73 eligible patients included a median age of 69 years (range 60-87 years), 49% female, 92% white, and a median KPS of 80 (range 60-100). As presented in Table 1, most had ≥3 comorbidities (55%), impaired physical function measured by Short Physical Performance Battery (70% had a score of 9 or less) and impaired cognition measured by Montreal Cognitive Assessment (64% had a score of 25 or less). Genetic risk categories included adverse (62%), intermediate (22%), and good-risk AML (16%). Patients had one or more of the following mutations: TET2 (26%), NPM1 (22%), RUNX1 (19%), ASXL1 (19%), TP53 (19%), DNMT3A (16%), IDH2 (15%), IDH1 (11%), FLT3 ITD (10%), FLT3 TKD (10%), biallelic CEBPA (4%), EZH2 (2%). Seven patients (10%) received intensive chemotherapy; CPX 351 (n=4) or 7+3 based regimen (n=3). Other patients received low-intensity chemotherapy: azacitidine or decitabine and venetoclax (n=43, 59%), decitabine or azacitidine alone (n=18, 24%) prior to approval of venetoclax, and other (n=5, 7%). The median time from diagnosis to therapy initiation was 6 days and from enrollment to therapy initiation was 1 day (range 0-13). Mortality at 30 days from diagnosis was 6.8% (95% confidence interval, CI 3.0-15.1%) and at 90 days was 21.9% (95% CI 14.0-32.7%). Mortality compared favorably to an unmatched historical cohort of patients ≥60 years treated at our center between 2011-2016, where 30-day mortality was 30% (95% CI 22-40%) and 90-day was 41% (95% CI 32-52%) (Future Oncol. 2019;15:1989-95). Conclusions: Our model to personalize AML therapy selection represents an innovative approach to precision medicine that incorporates both geriatric assessment for patient profiling and genetic profiling of leukemia cells. Geriatric assessment demonstrated high frequency of impairment in objective physical and cognitive function. Patients were able to start therapy within a median of 1 day following enrollment. Pragmatic aspects of the trial included broad eligibility criteria and co-management of patients with community oncologists. The results from our final analysis appear promising with lower rates of early mortality compared to unmatched historical controls.

ELN 2022 Favorable Genetic Risk Acute Myeloid Leukemia Treated with Venetoclax Plus Hypomethylating Agent: Predictors of Response and Survival

Background: The 2022 European LeukemiaNet (ELN) genetic-risk stratification for acute myeloid leukemia (AML), assigns favorable prognosis to t(8;21)(q22;q22.1)/ RUNX1:: RUNX1T1, inv(16)(p13.1q22) or t(16;16)(p13.1;q22)/ CBFB:: MYH1, NPM1 mutations without FLT3-ITD or adverse karyotype, and bZIP in-frame CEBPA mutations (Döhner , Blood, 2022 ). This risk stratification was derived from intensively treated patients; accordingly, prognostication in ELN favorable genetic risk AML, following venetoclax and hypomethylating agent (VEN-HMA) therapy, remains unclear and was the subject of the current study. Methods: Under an institutional review board approved minimum risk protocol, the Mayo Clinic database was searched to identify AML patients with favorable genetic risk, who received treatment with VEN-HMA in the frontline setting. All patients received at least one cycle of either azacitidine 75 mg/m 2 days 1-7 or decitabine 20 mg/m 2 days 1-5 with VEN dose adjusted based on azole antifungal prophylaxis. Genetic risk stratification and treatment response were assessed according to the 2022 ELN criteria. Survival was estimated from the time of VEN-HMA treatment start to last follow-up or death. Results: Patient characteristics A total of 46 newly-diagnosed AML patients with ELN 2022 favorable genetic risk [ NPM1 mutation, n=36 (78%), CEPBA bZIP mutation, n=7 (15%) and t(8;21)(q22;q22.1)/ inv(16)(p13.1q22), n=4 (9%)] received a median of 4 cycles (range 1-32) of VEN-HMA. Median age was 71 years, with 63% males, and 87% de novo AML. Additional mutations frequently involved TET2 in 17/43 (40%), DNMT3A in 14/45 (31%), SRSF2 in 10/43 (23%), K/NRAS in 10/45 (22%), IDH1 in 8/46 (17%), FLT3-TKD in 7/46 (15%), ASXL1 in 6/43 (14%) and IDH2 in 6/46 (13%),of informative cases.Myelodysplasia (MDS)-related gene mutations ( ASXL1, RUNX1, BCOR, EZH2, SRSF2, U2AF1, SF3B1, STAG2, and/or ZRSR2) were present in 15 of 40 (38%) of patients (93% males). Predictors of response Of the 39 (85%) patients that achieved complete remission, with (CR) ( n=24; 52%), or without count recovery (CRi) ( n=15; 33%); CR/CRi rates were not significantly higher in patients with NPM1 mutations (89%), t(8;21)(q22;q22.1)/ inv(16)(p13.1q22) (75%), or CEPBA bZIP mutations (67%) ( p=0.37). Among patients achieving CR/CRi, measurable residual disease by multiparametric flow cytometry was negative in 15 of 16 (94%) of evaluable cases after cycles 1 or 2. In addition, NPM1 qPCR was negative in 15 of 24 (63%) informative patients. Median time to response was 1.2 months with median response duration of 9.4 months. CR/CRi rates were significantly higher in females vs males (100% vs 76%, p=0.01), and in the absence vs presence of MDS-related gene mutations (96% vs 60%, p=0.004). Multivariable analysis confirmed superior response in the absence of MDS-related gene mutations ( p=0.04). Predictors of survival At a median follow-up of 10.6 months (range; 1.1-51 months), 21 patients (46%) have died, 9 relapsed (23% of those achieving CR/CRi), and 6 (13%) underwent allogeneic hematopoietic stem cell transplant. Median overall survival was 21 months with 1/2/3-year survival rates of 65%/41%/41% (Figure 1a); median relapse-free survival (RFS) was not reached; 1/2/3-year RFS rates were 81%/66%/57% (Figure 1b). Overall survival was superior in patients achieving CR/CRi (23 months vs 5.6 months; p<0.01), in females vs males (not reached vs 9.7 months; p<0.01), and in the absence of MDS-related gene mutations (not reached vs 5.6 months; p=0.01) (Figure 1c). Subsequent multivariable analysis identified female gender ( p=0.01), and absence of MDS-related mutations ( p=0.17) as independent predictors of superior survival. Similar results were obtained when analysis was restricted to NPM1 mutated patients. Conclusions: In the current retrospective study, VEN-HMA therapy in elderly/unfit AML patients with ELN 2022 favorable genetic risk, resulted in response rates that were comparable to those previously appreciated from published reports of patients receiving intensive induction therapy; however, follow-up in the current study was too short to accurately assess long-term overall and relapse-free survival impact. Our study also highlights the adverse prognosis retained by MDS-related gene mutations.

ELN Criteria for Cytoreduction Start Identify Patients with Polycythemia Vera at Higher Thrombotic Risk

Introduction Recently, the European Leukemia Net (ELN) recommended cytoreduction in patients (pts) with Polycythemia Vera (PV) at low risk (LR) (age <60 yrs & no previous thromboses) but carrying additional criteria for therapy start (CTS) ( Marchetti M et al, Lancet Haematol 2022). Little is known about: 1] efficacy of hydroxyurea (HU) in LR pts, high risk due to age >60 yrs (HR-AGE) or high risk due to previous thrombosis regardless of age (HR-THRO); 2] impact of CTS on thrombotic risk. Aims In a large cohort of HU-treated PV pts, we investigated if thrombotic risk was influenced by: 1] conventional risk factors for thrombosis; 2] ELN-defined complete response (CR) at 12 mos; 3] presence of CTS. Methods After IRB approval, data of 961 WHO2016-defined PV pts were retrospectively collected by 21 Hematology Centers. In April 2023, an update was performed in 10 participating Centers with specific focus on CTS at diagnosis and HU start; 504 HU-treated pts resulted eligible for this analysis. Therapy was at discretion of the treating hematologist. Pts were followed until death or data cut-off date. CTS evaluated for association with thrombosis included: persistent/progressive leukocytosis (100% increase if white blood cells (WBC) <10 x10 9/L or 50% increase if WBC>10 or WBC>15 at diagnosis and HU start); extreme persistent thrombocytosis (>1000 x10 9/L platelets (PLT) at diagnosis and HU start); progressive splenomegaly (increase of >5 cm from diagnosis); inadequate hematocrit (Hct) control (>6 PHL/yr; HCT >53% at diagnosis and HU start; PHL intolerance); uncontrolled cardiovascular risk factors (CVRF). Symptoms were present as the only ELN criterion in 40 patients, of whom none had thrombosis; therefore, they were not included in the analysis. Results 504 pts received HU: 81 pts were at LR and 423 (83.9%) were at HR (HR-AGE, no. 290, 57.5%; HR-THRO, no. 133, 26.4%). Median time on HU was 11.6 yrs (0.1-23.1). During HU, 53 pts had 69 thromboses (35 arterial) for an incidence rate of thrombosis (IR-thro) of 1.5 %p-y, comparably in LR and HR ( Table 1). Notably, IR-thro was equal in LR and HR-AGE (p=0.94), but significantly higher in HR-THRO pts (p=0.005 vs LR and p=0.009 vs HR-AGE). At 12 months, CR was achieved by 8.2%, 23% and 25% of LR, HR-AGE and HR-THRO pts, respectively (LR vs HR-AGE and HR-THRO, p<0.001 and p=0.003). Thrombosis-free survival (TFS) by landmark analysis at 12 months was significantly better in CR pts (p=0.01). Specifically, best TFS was observed in LR and HR-AGE pts with CR, while HR-THRO pts without CR had the worst TFR (p=0.009). CTS were observed in 255 (50.6%) pts: 48 LR (59.3%), 139 HR-AGE (47.9%) and 68 HR-THRO (51.1%). In the remaining LR pts, HU was triggered by mild thrombocytosis (<1000 x10 9/L) and/or mild leukocytosis (<15 x10 9/L) and/or mild splenomegaly (<5 cm from costal margin) and/or persistent systemic symptoms. CTS were associated to significantly increased of IR-thro in the overall cohort (p<0.001), in LR pts (p=0.04), in HR-AGE pts (p=0.02) and in HR-THRO pts (p=0.03) ( Table 1) . The impact of CTS was confirmed in the overall cohort both for arterial (1.30 vs 0.44 %p-y, p=0.01) and venous thrombosis (1.37 vs 0.44 %p-y, p=0.007). TFS at 5 yrs was 87% and 95% in pts with or without CTS (p<0.001) ( Fig.1a). In presence of CTS, TFS of LR and HR-AGE pts were comparable to HR-THRO pts without CTS ( Fig. 1b). In multivariate Cox analysis considering age>60 yrs, previous thrombosis, CTS, and CR to HU at 12 months, CTS and previous thrombosis remained associated with thrombotic risk (HR: 2.7, 95% CI: 1.4-5, p =0.002; HR: 2.4, 95% CI: 1.4-4.2, p =0.001). Finally, in 59 additional LR pts untreated with HU, IR-thro was 0.78 in absence of CTS, and 1.57 %p-y in presence of such criteria. Conclusions Albeit retrospective, this study shows for the first time that ELN criteria for therapy start including splenomegaly, leukocytosis, thrombocytosis, uncontrolled Hct and CVRF, identified an increased risk phenotype either in LR and HR pts treated with HU. This was confirmed also in HU-untreated pts. Also, lack of CR at 12 months was detrimental on TFS particularly in HR-THRO pts, and less significantly than CTS. These findings, that complement data from the Majic-PV trial ( Harrison CN et al, J Clin Oncol 2023), dictate better management of HU therapy, and call for greater attention to CTS and their integration into prognostic models that go beyond the two categories related only to age and thrombotic history.

How Induction Cycles before Remission Influence Long-Term Survival in Acute Myeloid Leukemia

Background ： Acute myeloid leukemia (AML) is an aggressive hematologic malignancy characterized by accumulation and expansion of immature myeloid cells in the bone marrow, peripheral blood and other tissues. Despite the progress made in mechanisms and approval of new therapeutics, the clinical outcome of AML remains suboptimal. The achievement of complete remission (CR) after induction chemotherapy is critical because the prognosis of refractory AML was especially unfavorable. However, little is known about the association between remission after first induction therapy and the overall survival (OS) in different subgroups of AML. Study Design and Methods: We retrospectively analyzed patients with newly diagnosed AML from January 2019 to August 2022. The diagnosis and treatment strategies were based on European Leukemia Net (ELN) criteria and National Comprehensive Cancer Network (NCCN) guideline. Composite complete remission (CRc) rate (CR+CR with incomplete recovery [CRi]) were assessed at the completion of induction or re-induction therapy. Minimal residual disease (MRD) was assessed using multiparameter flow cytometry with a minimum sensitivity of 0.1%. OS was measured from the day of diagnosis until death or the last follow-up date. Results : In total, 679 patients were included and the median age was 59.0 (range, 14.0-93.0) years old. There were 56.8% (386/679) of patients who achieved CRc after the induction therapy (group A), 18.1% (123/679) achieved CRc after the re-induction therapy (group B). The median follow-up period was 24.2 months. Even though there was no significant difference between group A and group B on OS, group A exhibited improved OS when censored at allogenic hematopoietic stem cell transplantation (HSCT) compared to that in group B (group A vs group B:3-year OS rates 65.7% vs 51.1%，p=0.004，Figure A). We further explored the effects of remission depth on survival. The results showed that, after induction therapy, patients achieved CR exhibited superior OS compared with that in CRi (CR vs. CRi, 3-year OS rates 69.4% vs 51.6%, p=0.006). Also, compared with these patients who failed to achieved MRD negativity within re-induction therapy, patients achieved MRD negativity within re-induction therapy showed superior OS when censored at HSCT (MRD- vs. MRD+, 3-year OS rates 64.7% vs 34.9%, p=0.040). After the first reduction therapy, patients achieved CRc but MRD positive benefit from HSCT (HSCT vs Non-HSCT, 3-year rates 83.0% vs 57.9%, p=0.017), but in patients with MRD negativity, HSCT did not improve the survival outcomes (HSCT vs Non-HSCT, 3-year rates 76.8% vs 65.7%, p=0.078). The next-generation sequencing (NGS) results were available in 520 patients. Based on the 2022 ELN risk stratification, the 3-year OS rates were 60.3%, 44.2% and 35.0% in favorable, intermediate and adverse group, respectively. Moreover, there were 43, 47, 60 patients in favorable, intermediate, and adverse subgroups underwent HSCT subsequently. In intermediate risk subgroup, patients who failed to achieve CRc after the first induction therapy, HSCT may serve as an effective intervention to prolong survival (3-year rates 100% vs 12.1%, P<0.001,). On the contrary, patients who achieved CRc in induction therapy, the overall survival were not influenced by HSCT status (3-year rates 81.5% vs 31.7%, p=0.153, Figure B). Conclusion: Our finding indicated that remission after the first cycle of induction therapy may be a prognostic factor for OS. Moreover, earlier and deeper remission may lead to improved survival. For those patients in intermediate risk group, who achieved CRc in induction therapy or achieved CRc with MRD negativity within re-induction therapy, HSCT may not influence the survival outcome.

Oral Decitabine/Cedazuridine with Venetoclax in High-Risk Myelodysplastic Syndrome or Chronic Myelomonocytic Leukemia: Analysis By Different Response Criteria

Introduction: Patients with higher-risk myelodysplastic syndromes (HR-MDS) have poor survival. The standard of care for HR-MDS are hypomethylating agents (HMA). The addition of venetoclax (Ven) to HMA has been shown to improve outcomes in acute myeloid leukemia (AML) and potentially in HR-MDS. The combination of oral decitabine/cedazurridine (DEC-C) with Ven has been shown to induce high response rates in patients with HR-MDS. Herein we analyze the responses of patients treated with DEC-C with Ven according to different response criteria. Additionally, we analyze the cytogenetic responses and mutation dynamics. Methods: We analyzed patients included in a phase I/II single center clinical trial (NCT04655755). diagnosed with treatment-naïve MDS (IPSS intermediate-2 or high) or CMML with excess blasts. Responses were analyzed by the International Working Group (IWG) criteria for MDS of 2006 and 2023, as well as the European LeukemiaNet (ELN) criteria for AML (2022). Cytogenetic responses and mutations were analyzed by conventional cytogenetics/FISH and NGS, respectively. Results: Between January 2021 and January 2023, 39 patients were enrolled. The median age of the entire cohort was 71 years old (range, 27-94), with 26 (70%) male patients. The WHO 2016 diagnosis was MDS with excess-blasts 1 (n=6, 16%), MDS with excess-blasts 2 (n=24, 65%), CMML-2 (n=6, 16%) and atypical chronic myeloid leukemia (n=1, 3%). The cytogenetic risk according to IPSS was good (n=11, 30%), intermediate (n=12, 32%) and adverse (n=14, 38%). The most common mutations found were ASXL1 (n=18, 49%), RUNX1 (n=14, 38%), SRSF2 (n=11, 30%), TET2 (n=8, 22) and TP53 (n=7, 19%). According to the IWG-2006 classification, the overall response rate was 95%, with 17 (43%) patients achieving complete remission (CR) and 20 (52%) patients achieving marrow CR (mCR). When using the IWG-2023 criteria, the overall response rate was 82%, with 23 (59%) patients achieving CR and 9 (23%) achieving CR with limited count recovery/CR with partial hematologic recovery. Of note, 5 patients achieved mCR according to the IWG-2006 but did not achieved CR by the IWG-2023 due to the peripheral blood count. Moreover, we did not find differences in overall survival (OS) between CR and mCR (OS of 60% for both groups, p=0.5). When using the ELN 2022 criteria for acute myeloid leukemia, the ORR was 80% with 2 patients not responding and 2 patients in a morphologic leukemia-free status (MLFS) (Figure 1). Both IWG-2006 and 2023 define cytogenetic response as complete disappearance of chromosomal abnormalities present at diagnosis. 14 patients out of 29 (48%) with cytogenetic abnormalities achieved cytogenetic response after a median of 2 courses of treatment (1-9). The IPSS cytogenetic risk of patients responding was good in 1 (7%) patient, intermediate in 8 (57%) patients and poor in 5 (36%) patients, including 3 patients with complex karyotype. Among patients not achieving cytogenetic response, 5 (33%) and 10 (67%) patients had an intermediate and adverse IPSS cytogenetic risk, respectively. Although molecular responses are not defined in the IWG-2023, we studied the molecular dynamics between diagnosis and best response. 23 patients of the study had molecular data in paired samples at diagnosis and at CR while on treatment. When analyzing the dynamics of each individual mutation, STAG2 (11/11, 100%), NRAS (3/3, 100%), BCOR (4/5, 80%) and IDH1 (2/3, 67%) showed the higher rate of clearance from diagnosis to CR. On the contrary, ZRSR2 (3/4, 75%), U2AF1 (3/4, 75%), TP53 (3/4, 75%), SRSF2 (5/7, 71%) and ASXL1 (10/14, 71%) showed the higher rate of persistence from diagnosis to CR (Figure 2). Among all patients in the study, 19 (49%) proceeded to hematopoietic stem cell transplantation (HSCT). Eleven patients had molecular data after HSCT, all achieving complete mutation clearance after HSCT. Conclusion: DEC-C with Ven achieves a high rate of responses, although with the IWG-2023 criteria responses are lower due to the disappearance of mCR and more strict criteria in terms of peripheral blood count recovery. Almost half of patients with cytogenetic abnormalities can acquire cytogenetic responses, including poor risk cytogenetics. Subclonal mutations (like STAG2 or NRAS) can be cleared with this combination while founding mutations (like ASXL1 or TP53) tend to persist, although HSCT has a potential to eliminate them.

Venetoclax + Cladribine + Low-Dose Cytarabine in Acute Myeloid Leukemia Relapsed or Refractory to Venetoclax + Hypomethylating Agent

Background Venetoclax (Ven) in combination with hypomethylating agent (HMA) is the standard treatment for newly diagnosed elderly/unfit patients with acute myeloid leukemia (AML). Treatment options for patients with relapsed/refractory (RR) disease following Ven-HMA are limited in the absence of targetable mutations. In a recent phase 2 study, the addition of Ven to cladribine (CDA) plus low-dose cytarabine (LDAC), in newly-diagnosed elderly/unfit AML, resulted in complete remission with (CR) or without (CRi) count recovery rate of 93% ( J Clin Oncol 20;40(33)). In the current study, we share our experience with this regimen in patients relapsed or refractory to Ven-HMA, treated outside of clinical trials. Methods Under an institutional review board approved minimum risk protocol, the Mayo Clinic (MN, AZ, FL) database was searched to identify patients with AML who failed treatment with Ven-HMA and subsequently received at least one cycle of salvage therapy with Ven-CDA-LDAC: Ven 100-400 mg, dose adjusted, d1-21, CDA 5 mg/m 2 d1-5, LDAC 20 mg twice daily d1-10, outside of clinical trials. Cytogenetic and molecular studies were performed at the time of Ven-CDA-LDAC initiation in most cases, by conventional karyotype and next-generation sequencing, respectively. The 2022 European LeukemiaNet (ELN) criteria were applied to define risk and response. Survival was calculated from the time of Ven-CDA-LDAC treatment start to last follow-up or death. Results Patient characteristics A total of 39 RR AML patients (median age 65 years, 67% male, 64% de novo), with prior exposure to Ven-HMA, received Ven-CDA-LDAC (median 1 cycle; range 1-5). Study patients had received one ( n=16), two ( n=14), three ( n=5), four ( n=2), five ( n=1) or nine ( n=1) prior therapies, including Ven-HMA. Nine (23%) patients had relapsed following allogeneic hematopoietic stem cell transplant (AHSCT). ELN cytogenetic risk included intermediate (46%, n=18), and adverse (54%, n=21). Mutations involved TP53 in 9 patients (23%), K/ NRAS in 8 (21%), RUNX1 in 7 (18%), TET2 in 6 (15%), ASXL1 in 5 (13%), and STAG2 in 5 (13%). Response and toxicity Eleven (28%) patients achieved CR ( n=2; 5%) or CRi ( n=9; 23%); median time to response was 1 month and median response duration 3.4 months. In addition, 2 (5%) patients each experienced partial remission (PR) and bone marrow aplasia without fulfilling criteria for morphologic leukemia free state. Measurable residual disease (MRD) was negative by multiparametric flow cytometry in 2 of 7 (29%) informative CR/CRi cases. CR/CRi rates were higher in females (54% vs 15%; p=0.01), de novo vssecondary AML (40% vs 7%; p=0.02), and absence of adverse karyotype (50% vs 9%; p<0.01), K/NRAS (35% vs 0%, p=0.01), ASXL1 (32% vs 0%, p=0.05), or STAG2 mutations (32% vs 0%, p=0.05) (Table 1). Multivariable analysis confirmed superior response in de novo AML (p<0.01), absence of adverse karyotype, (p<0.01), and absence of K/NRAS mutations (p=0.02). CR/CRi rates were not significantly affected by relapsed vs refractory setting ( p=0.95), number of prior therapies ( p=0.51), prior AHSCT ( p=0.64), or TP53 mutations ( p=0.64) (Table 1). Treatment-emergent toxicities included infections (49%, n=19), comprising bacteremia ( n=11), pneumonia ( n=10), peri-rectal abscess ( n=6), and laboratory evidence of tumor lysis syndrome (3%, n=1). Survival At a median follow-up of 3.9 months, from initiation of Ven-CDA-LDAC, 31 deaths (79%), 6 relapses (15%), and 7 AHSCT (18%; including 5 in CR/CRi, 1 in aplasia) were documented. Median survival following Ven-CDA-LDAC was 4.6 months, and superior in the presence vs absence of CR/CRi (8.1 vs 2.9 months; p=0.01), and in patients receiving AHSCT (10.5 vs 3.4 months; p=0.02). Absence of adverse karyotype was also associated with superior survival (6 vs 3.4 months; p=0.05). Multivariable analysis confirmed the favorable survival impact of CR/CRi ( p=0.03) and AHSCT ( p=0.05); survival impact was not apparent for secondary AML ( p=0.29) or K/NRAS ( p=0.70) or TP53 ( p=0.10) mutations. Conclusions The current study suggests transplant bridging value for Ven-CDA-LDAC in AML patients relapsed or refractory to Ven-HMA, especially in the absence of adverse karyotype or K/NRAS mutation. AHSCT and achievement of CR/CRi appear to be indispensable for favorable post-Ven-CDA-LDAC survival.

Venetoclax-Based Therapy before Allogeneic Hematopoietic Cell Transplantation for Acute Myeloid Leukemia

Introduction The BCL-2 inhibitor venetoclax (VEN) is effective in older patients with untreated acute myeloid leukemia (AML). Few reports exist on the use of VEN as a bridging therapy for allogeneic hematopoietic cell transplantation (HCT) for AML. Previous studies have shown that NPM1 and IDH2 gene mutations are associated with high response rates to VEN therapy. We performed a retrospective cohort study to analyze the efficacy of VEN-based bridging therapy before HCT. Methods We included 46 patients who were eligible for HCT and received bridging therapy combined with VEN between April 2021 and June 2023 at our center. We evaluated response rates to VEN and HCT outcomes. None of the patients received VEN prior to the study. The response rate to VEN was evaluated using the 2022 European LeukemiaNet (ELN) criteria. We estimated overall survival (OS) using the Kaplan-Meier method, log-rank test, and Gray's test for univariate analysis of cumulative incidence of relapse (CIR) and non-relapse mortality (NRM). We used the Cox proportional hazards model for a multivariate analysis of OS. We extracted DNA from the bone marrow or peripheral blood, and analyzed gene mutations using next-generation sequencing (NGS), targeting 70 genes known to be recurrently mutated in myeloid malignancies. Results Of the 46 patients, 32 had de novo AML, 7 had de novo MDS/AML, 5 had secondary AML, 1 had secondary MDS/AML, and 1 had myeloid sarcoma. The median age was 59 (21-70) years. Nineteen were women and 7 had a history of HCT. The regimens combined with VEN were azacitidine in 39 cases and low-dose cytarabine in 7. According to the 2022 ELN risk classification by genetics at diagnosis, 7 were favorable, 11 were intermediate, and 27 were at adverse risk. Nine patients were in hematological complete remission (CR) / CR with incomplete count recovery (CRi) while 37 were not, when VEN was initiated. The maximum response rates among the patients who started VEN treatment in the non-CR group were: 18 with CR/CRi (49%) and no response in 19 (51%). The median time from the first dose of VEN to HCT was 70 (27-315) days. Forty-one patients underwent HCT and 19 (43%) were in CR/CRi at HCT. The reasons for discontinuation of VEN were HCT in 34 cases, failure in 9, and adverse events in 4 (hematological toxicity in 3 cases and infection in 1). Sixteen patients died due to primary disease (n=9), infection (n=5), thrombotic microangiopathy (n=1), and multi-organ failure (n=1). The median post-HCT observation period of survivors was 156 (25-775) days, and at 1-year after HCT, OS was 49.6% (95% CI: 28.0-67.9), CIR was 40.6% (95% CI: 24.1-56.6) and NRM was 15.2% (95% CI: 5.5-29.5). At 1-year after HCT, outcomes of the patients who were in CR/CRi at HCT was better than that of those who were not (OS, 80.8% vs. 26.4%, p=0.002; CIR, 13.4% vs. 61.8%, p<0.01; NRM, 0% vs. 26.7%, p<0.05). In 35 of the patients who underwent the first HCT, the 1-year OS was 88.9% in those who were in CR and 36.5% in those who were not (p=0.015). Thirty cases were non-CR at the start of the VEN regimen prior to their first HCT. This group had a 1-year OS of 57.8% (95% CI, 27.4-79.3). In 11 patients who achieved CR before HCT and 18 others who did not, the 1-year OS rates were 83.3% and 39.9%, respectively (p=0.10). Genetic analysis was performed by NGS in 37 patients before starting VEN, revealing mutations in TP53 (n=9), RUNX1 (n=7), IDH1 (n=6), ASXL1 (n=6), and DNMT3A (n=6) (Fig. 1A). Alterations in MDS-related genes (n=20) and kinase-related genes ( KIT, PTPN11, FLT3, KRAS, n=11) were frequent. Among the patients receiving their first HCTs, the 1-year OS was 0% in the group with TP53 mutations, and 63.9% in the wild-type TP53 group (p=0.04). The OS was worse in patients with mutated TP53 or kinase-related genes (n=19) than those without either mutation (n=15) (Fig. 1B, 1-year OS 28.7% vs. 72.9%, p=0.029). A multivariate analysis of OS revealed that patients who were not in CR at HCT (HR, 25.01 [95% CI, 2.406-259.9], p=0.007), those who previously underwent HCT (HR, 36.81 [95% CI, 4.599-294.7], p=0.035), and those with TP53 or kinase-related gene mutations (HR, 6.311 [95% CI, 1.137-350.0], p=0.035) had significantly lower OS rates. There was no significant difference in OS between the different ELN risk categories. Conclusions Non-CR at the time of HCT, a history of HCT, and mutations in TP53 or kinase-related genes were found to be independent poor prognostic factors for OS after VEN-based bridging treatment followed by HCT.

Modification of the ELN Classification 2022 Refines Risk Assessment in MDS/AML Patients

Background: The International Consensus Classification (ICC) introduced MDS/AML as a novel myeloid disease entity defined by 10-19% blasts in the absence of AML-defining recurrent genetic abnormalities. MDS/AML patients should be eligible for AML-like treatment approaches in clinical trials. It has recently been shown that the AML-based risk classification according to European Leukemia Net (ELN) 2022 criteria fails in MDS/AML while an MDS-based risk classification according to Molecular International Prognostic Scoring System (IPSS-M) was applicable (Huber S et al. EHA 2023). Our aim was to refine the ELN 2022 criteria based on genome sequencing data to better reflect the outcome in this overlap category of MDS and AML. Methods: Non-therapy-related cases of 403 MDS/AML and 686 AML patients classified according to ICC were included. Bone marrow samples were analyzed by cytomorphology, cytogenetics and targeted NGS panel sequencing (median coverage 1500x). Overall survival (OS) was assessed in all AML patients and in a subcohort of 137 MDS/AML patients (median follow-ups: 5.6 and 10.2 years, respectively) in whom also whole genome sequencing (median coverage 100x) was performed. Results: MDS/AML patients had a median age of 74 years (female/male: 153/250). They were subclassified according to ICC as MDS/AML with mutated TP53 (14%), with myelodysplasia-related (MR) gene mutations (67%) or MR cytogenetic abnormalities (5%), or not otherwise specified (14%). Cytogenetic aberrations were detected in 173/403 (43%) cases including del(5q) (18%), -7/del(7q) (13%), and complex karyotypes (16%). Molecular aberrations were detected in 376/403 (93%) cases with a median number of 3 mutations. Most frequent gene mutations were ASXL1 (40%), TET2 (32%), SRSF2 (32%), and RUNX1 (29%); TP53 was mutated in (14%) (details in Figure 1A). Grouping of the MDS/AML cohort according to the ELN 2022 guidelines showed: no MDS/AML patient fulfilled criteria for the favorable ELN risk group, only 14% were classified as intermediate risk, and the vast majority (86%) as adverse risk. The survival of MDS/AML patients substantially differed from a bona fide AML cohort, in particular for adverse risk (Figure 1B left). To more adequately risk stratify MDS/AML patients, we aimed to modify current ELN criteria. Notably, in multivariate Cox regression analysis in addition to -7/del(7q) (hazard ratio/HR: 5.5) and mutated RUNX1 (HR: 2.2), also mutations in EZH2 (HR: 2.2) and in SF3B1 (HR: 0.3) remained significant prognostic markers for OS (all p<0.05). Following this, we defined three hierarchically defined risk groups for MDS/AML patients i) adverse (criteria: complex karyotype, -7/del(7q), mutation in TP53, RUNX1, EZH2), ii) intermediate (criteria: del(5q), mutation in ASXL1, SRSF2, U2AF1, ZRSR2, BCOR or STAG2) and iii) favorable (criteria: sole SF3B1 mutation or none of the abnormalities defined above). Overall, 149 MDS/AML patients (37%) were re-grouped compared to ELN 2022 categories resulting in 49% adverse, 35% intermediate and 16% favorable cases. Survival analysis revealed strong prognostic separations of the three new MDS/AML risk categories with median OS of 1.3 years for adverse, 3.1 years for intermediate and 8.1 years for favorable (overall p<0.001; Figure 1B right). The general survival prediction within MDS/AML was improved in the modified version compared to the original ELN 2022 (corrected Akaike information criterion using Cox models: 876 for modified vs. 902 for ELN 2022). Of note, the outcome of adverse risk MDS/AML according to the modified ELN was comparable to the OS of adverse risk AML according to the original ELN (median OS: 1.3 vs 0.7 years; p=0.304). Conclusion: ForMDS/AML patients, AML-based risk classification according to ELN 2022 guidelines is not applicable as the vast majority of cases are categorized into the adverse risk group based on mutations in splicing factor genes and other secondary-type mutations. Modification of the ELN risk categories reflects the partly MDS-based biology of the disease and substantially improves the prognostic stratification. Most importantly, patients with adverse outcome potentially benefitting from inclusion into clinical trials for novel substances are identified. The validity of the modified risk classification for MDS/AML patients undergoing specific treatment regimens remains to be confirmed in forthcoming studies.

Real-World Clinical Characterisation of Polycythaemia Vera Patients from a Prospective Registry in Portugal: Is Resistance to Hydroxyurea a Reality?

Patients with polycythaemia vera (PV) are at increased risk of thrombosis and haemorrhages. Although hydroxyurea (HU) has been the frontline therapy for patients at high risk of vascular complications, about 25% of patients develop resistance/intolerance to this therapy. The aim of this non-interventional, multicentre cohort study was to understand the clinical characteristics and HU treatment response of Portuguese PV patients. HU resistance/intolerance was defined according to adjusted European LeukemiaNet (ELN) criteria. In total, 134 PV patients with a mean (SD) disease duration of 4.8 (5.0) years were included and followed up for 2 years. At baseline, most patients were ≥60 years old (83.2%), at high risk for thrombotic events (87.2%), and receiving HU therapy (79.1%). A total of 10 thrombotic events and 8 haemorrhagic events were reported, resulting in a 5-year probability of thrombo-haemorrhagic events of 17.2%. Haematocrit (p = 0.007), haemoglobin (p = 0.012) and MPN10 symptom score (12.0 (11.6) vs. 10.3 (9.1); p = 0.041) decreased significantly at the 24-month visit compared to baseline. Overall, 75.9% of patients met at least one of the adjusted ELN criteria for HU resistance, and 14.4% of patients remained on HU throughout the study. The results from this real-world study may help identify the subset of patients at higher risk for disease sequelae who may benefit from earlier second-line treatment.

A retrospective study of cladribine and low-dose cytarabine-based regimens for the treatment of chronic myelomonocytic leukemia and secondary acute myeloid leukemia.

Patients with higher risk chronic myelomonocytic leukemia (CMML) have limited therapeutic options beyond hydroxyurea and hypomethylating agents (HMAs). Regimens based on a backbone of cladribine (CLAD), low-dose cytarabine (LDAC), and an HMA are effective low-intensity therapies for acute myeloid leukemia (AML). The authors conducted a retrospective chart review to evaluate the efficacy of CLAD/LDAC/HMA in CMML and secondary acute myeloid leukemia (sAML) arising from CMML. Responses were evaluated according to the 2006 International Working Group criteria for CMML and the 2017 European LeukemiaNet criteria for AML. The overall survival (OS), leukemia-free survival (LFS), and duration of response were evaluated with the Kaplan-Meier method. Patients were stratified on the basis of prior HMA exposure. The authors identified 21 patients with CMML (eight with HMA-naive CMML and 13 with HMA-failure CMML) and 33 patients with sAML (11 with HMA-naive sAML and 22 with HMA-failure sAML) treated with CLAD/LDAC/HMA-based regimens. The CMML cohort was enriched for high-risk features (proliferative type, elevated blasts, and RAS/MAPK mutations). The overall response rate was 33% in CMML (50% in HMA-naive CMML and 23% in HMA-failure CMML) and 48% in sAML (82% in HMA-naive sAML and 32% in HMA-failure sAML). The median OS was 14.4, 8.8, 42.9, and 2.9months for HMA-naive CMML, HMA-failure CMML, HMA-naive sAML, and HMA-failure sAML, respectively. The median LFS was 14.4 and 3.9months for HMA-naive CMML and HMA-failure CMML, respectively. CLAD/LDAC/HMA-based regimens are effective in a subset of patients with higher risk CMML and sAML arising from CMML who have not previously experienced HMA failure. These findings must be confirmed in prospective studies.

Comparison and validation of the 2022 European LeukemiaNet guidelines in acute myeloid leukemia.

Risk stratification in acute myeloid leukemia (AML) remains principle in survival prognostication and treatment selection. The 2022 European LeukemiaNet (ELN) recommendations were recently published, with notable updates to risk group assignment. The complexity of risk stratification and comparative outcomes between the 2022 and 2017 ELN guidelines remains unknown. This comparative analysis evaluated outcomes between the 2017 and 2022 ELN criteria in patients enrolled within the multicenter Beat AML cohort. Five hundred thirteen patients were included. Most patients had 1 or 2 ELN risk-defining abnormalities. In patients with ≥2 ELN risk-defining mutations, 44% (n= 132) had mutations spanning multiple ELN risk categories. Compared with ELN 2017 criteria, the updated ELN 2022 guidelines changed the assigned risk group in 15% of patients, including 10%, 26%, and 6% of patients categorized as being at ELN 2017 favorable-, intermediate-, and adverse-risk, respectively. The median overall survival across ELN 2022 favorable-, intermediate-, and adverse-risk groups was not reached, 16.8, and 9.7 months, respectively. The ELN 2022 guidelines more accurately stratified survival between patients with intermediate- or adverse-risk AML treated with induction chemotherapy compared with ELN 2017 guidelines. The updated ELN 2022 guidelines better stratify survival between patients with intermediate- or adverse-risk AML treated with induction chemotherapy. The increased complexity of risk stratification with inclusion of additional cytogenetic and molecular aberrations necessitates clinical workflows simplifying risk stratification.