High-risk Myelodysplastic Syndrome Patients Research Articles

Combining 5-azacitidine with the E-selectin antagonist uproleselan is an effective strategy to augment responses in myelodysplasia and acute myeloid leukaemia.

The interaction of acute myeloid leukaemic (AML) blasts with the bone marrow (BM) microenvironment is a major determinant governing disease progression and resistance to treatment. The constitutive expression of E-selectin in the vascular compartment of BM, a key endothelial cell factor, directly mediates chemoresistance via E-selectin ligand/receptors. Despite the success of hypomethylating agent (HMA)-containing regimens to induce remissions in older AML patients, the development of primary or secondary resistance is common. We report that following treatment with 5-azacitidine, promoter regions regulating the biosynthesis of the E-selectin ligands, sialyl Lewis X, become further hypomethylated. The resultant upregulation of these gene products, in particular α(1,3)-fucosyltransferase VII (FUT7) and α(2,3)-sialyltransferase IV (ST3GAL4), likely causes functional E-selectin binding. When combined with the E-selectin antagonist uproleselan, the adhesion to E-selectin is reversed and the survival of mice transplanted with AML cells is prolonged. Finally, we present clinical evidence showing that BM myeloid cells from higher risk MDS and AML patients have the potential to bind E-selectin, and these cells are more abundant in 5-azacitidine-non-responsive patients. The collective data provide a strong rationale to evaluate 5-azacitidine in combination with the E-selectin antagonist, uproleselan, in this patient population.

Abstract CT060: Phase 1 study of azacitidine in combination with evorpacept for higher-risk myelodysplastic syndrome (MDS)

Abstract Background:Evorpacept (EVO) is a high affinity CD47-blocking fusion protein with an inactive human immunoglobulin Fc region designed to enhance the activity of other anti-neoplastic therapies with minimal additional toxicity. Here, we present final phase 1 results from the ASPEN-02 study. Methods:ASPEN-02 is an open-label, multicenter phase 1/2 study designed to evaluate the safety and activity of EVO in combination with azacitidine (AZA) in subjects with newly diagnosed (ND) higher-risk (HR) or relapsed/refractory (R/R) MDS. Adult subjects with ND HR (IPSS-R > 3.5) or R/R MDS were enrolled into phase 1 cohorts receiving escalating doses of EVO (20 mg/kg Q2W, 30 mg/kg Q2W, and 60 mg/kg Q4W) combined with AZA (75 mg/m2 IV/SC x 7d) in a 28-day treatment cycle. A phase 1 dose expansion portion enrolled adults with ND HR MDS into two dosing cohorts determined to be safe at EVO 40 mg/kg Q4W and 60 mg/kg Q4W. This clinical trial is registered at clinicaltrials.gov: NCT04417517. Results: As of June 2, 2023, 65 subjects were treated in the phase 1 portion, including 13 subjects with R/R MDS [EVO doses of 20 mg/kg Q2W (n=1) or 60 mg/kg Q4W (n=12)], and 52 subjects with ND HR MDS [EVO doses of 40 mg/kg Q4W (n=23) and 60 mg/kg Q4W (n=29)]. Of 52 ND HRMDS subjects, 9 (17.3%) had therapy-related MDS. Multi-hit TP53 mutations were present at baseline in 2/13 (15.4%) R/R MDS and 3/52 (5.8%) ND HR MDS patients. 13/13 (100%) R/R MDS patients had received prior hypomethylating agents or cytotoxic chemotherapy. Median age was 70 (range 24 - 88) years, and baseline ECOG scores were 0 (n=27, 41.5%), 1 (n=31, 47.7%), or 2 (n=7, 10.8%). No dose-limiting toxicity was observed, and a maximum tolerated dose (MTD) was not reached. Treatment-emergent AEs and treatment-related AEs for EVO were reported in 65/65 (100%) and 35/65 (53.8%) subjects respectively; discontinuation, however, was infrequent. Seven (10.8%) subjects experienced a serious adverse event related to EVO. There were no EVO-related deaths on study. Preliminary PK indicated dose-proportional pharmacokinetics consistent with prior studies. Objective response [complete remission (CR), partial remission (PR), marrow CR (mCR), hematologic improvement (HI)], per modified International Working Group 2006 criteria, was observed in 19/52 (36.5%) ND HR [CR=8, mCR=9, HI=2] and 2/13 (15.4%) R/R [mCR=2] MDS subjects. Conclusion:The myeloid checkpoint inhibitor EVO was well tolerated in combination with AZA with an initial safety and activity profile comparable to that of historical AZA monotherapy. Additional updated data will be provided at the time of presentation. Citation Format: Guillermo Garcia-Manero, Bart L. Scott, Ashwin Kishtagari, Srinivasa R. Sanikommu, Aref Al-Kali, Je-Hwan Lee, Juan M. Bergua Burgues, Maria Diez-Campelo, Harry P. Erba, Carmen Garcia-Hernandez, Guillermo Sanz Santillana, Casey O'Connell, Jun-Ho Jang, Dong-Yeop Shin, Hamid Sayar, Mayank Rao, Richard S. Schwartz, Grace An, Feng Jin, Alison J. Forgie, Athanasios C. Tsiatis, Jessica K. Altman. Phase 1 study of azacitidine in combination with evorpacept for higher-risk myelodysplastic syndrome (MDS) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT060.

Abstract 3129: BYON4413, an in vivo active CD123-targeting antibody-drug conjugate, combines effectively with azacitidine and venetoclax in acute myeloid leukemia cell lines

Abstract Background: CD123, the alpha chain of the interleukin-3 receptor (IL-3Rα), is overexpressed in multiple hematologic malignancies and found particularly highly expressed on the surface of acute myeloid leukemia (AML) cells. Furthermore, increased CD123 expression on leukemic stem cells relative to non-neoplastic hematopoietic stem cells makes CD123 an attractive tumor-associated target for an antibody-drug conjugate (ADC). BYON4413 is an ADC that consists of a novel humanized IgG1 anti-CD123 antibody site-specifically conjugated with Byondis' proprietary duocarmazine linker-drug technology, ByonZine® and ByonShieLD®. The efficacy of BYON4413 is studied as monotherapy and in combination with azacitidine and venetoclax (AZA/VEN), since the AZA/VEN regimen is the standard of care (SOC) for AML patients who are ineligible for intensive chemotherapy. Method: A panel of CD123+ and CD123- hematological cell lines and AML patient-derived bone marrow mononuclear cells (BMMCs)/peripheral blood mononuclear cells (PBMCs) were utilized in in vitro studies to determine the cytotoxic effects of BYON4413. The induction of apoptosis and cell killing by BYON4413 in a triple combination with AZA/VEN was studied in vitro using the CD123+ AML cell lines MOLM-13 and MV4-11. AML patient and cell line-derived xenograft models were used to investigate the in vivo efficacy of BYON4413. Results: In vitro studies with human AML cell lines show that BYON4413 is highly effective in eradicating CD123+ cells while having little impact on CD123- cells. These results were confirmed ex vivo with AML patient-derived BMMCs/PBMCs. BYON4413 effectively killed AML patient-derived blasts while largely sparing healthy hematopoietic cells. The triple combination of BYON4413 with AZA/VEN enhanced both apoptosis and cell killing of AML cell lines compared to the singular BYON4413 treatment. In vivo studies demonstrate that BYON4413 is remarkably efficient at reducing the tumor burden in AML patient- and cell line-derived xenograft models. Conclusions: Preclinical studies show that BYON4413 has potential to be an effective targeted therapy against CD123+ hematological malignancies such as AML. The enhanced efficacy of BYON4413 together with AZA/VEN suggests that a clinical benefit from the triple combination may be achievable and is worth further exploration. A first-in-human dose-escalation and expansion trial with BYON4413, designed to enroll R/R AML and high-risk MDS patients, is scheduled to start in Q2 2024. Citation Format: Miranda M.C. van der Lee, Tanja van Achterberg, Kaylee Hersmus, Annet Brouwers-Vos, Monique van der Vleuten, Maurien Pruis, Wendy Kappers, Gijs Verheijden, Gerwin Huls, Glenn van Wigcheren, Ruud Ubink, Aloys Sesink, Alyson MacInnes, Jan Jacob Schuringa, Wim Dokter. BYON4413, an in vivo active CD123-targeting antibody-drug conjugate, combines effectively with azacitidine and venetoclax in acute myeloid leukemia cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3129.

Analyzing Blood Cells of High-Risk Myelodysplastic Syndrome Patients Using Interferometric Phase Microscopy and Fluorescent Flow Cytometry.

Myelodysplastic syndromes (MDSs) are a group of potentially deadly diseases that affect the morphology and function of neutrophils. Rapid diagnosis of MDS is crucial for the initiation of treatment that can vastly improve disease outcome. In this work, we present a new approach for detecting morphological differences between neutrophils isolated from blood samples of high-risk MDS patients and blood bank donors (BBDs). Using fluorescent flow cytometry, neutrophils were stained with 2',7'-dichlorofluorescin diacetate (DCF), which reacts with reactive oxygen species (ROS), and Hoechst, which binds to DNA. We observed that BBDs possessed two cell clusters (designated H and L), whereas MDS patients possessed a single cluster (L). Later, we used FACS to sort the H and the L cells and used interferometric phase microscopy (IPM) to image the cells without utilizing cell staining. IPM images showed that H cells are characterized by low optical path delay (OPD) in the nucleus relative to the cytoplasm, especially in cell vesicles containing ROS, whereas L cells are characterized by low OPD in the cytoplasm relative to the nucleus and no ROS-containing vesicles. Moreover, L cells present a higher average OPD and dry mass compared to H cells. When examining neutrophils from MDS patients and BBDs by IPM during flow, we identified ~20% of cells as H cells in BBDs in contrast to ~4% in MDS patients. These results indicate that IPM can be utilized for the diagnosis of complex hematological pathologies such as MDS.

Abstract P26: Altered RNA Export Sensitizes to Nuclear Export Inhibition in SF3B1 Mutant MDS

Abstract SF3B1 mutations, the most frequent spliceosomal alterations across cancers, occur in 25% of myelodysplastic syndromes (MDS) patients yet lack effective therapies. Two phase 2 clinical trials with the XPO1 inhibitors in high-risk MDS revealed increased activity in patients with SF3B1 mutations. XPO1 (Exportin-1) plays a role in the transport of multiple RNA species, including small nuclear RNAs (snRNAs) out of the nucleus. Given the role of XPO1 in exporting snRNAs, which form the catalytic portion of the spliceosome, we hypothesized that XPO1 inhibition may preferentially affect SF3B1-mutant cells and that SF3B1-mutant high-risk MDS patients would have a better response to rational targeted drug combinations with XPO1 inhibitors. To evaluate the mechanism underlying the preferential sensitivity of SF3B1-mutant cells to XPO1 inhibition, we conducted subcellular RNA sequencing before and after XPO1 inhibition in SF3B1 wildtype and mutant cells. Transcriptomic analysis revealed increased global retention of RNA transcripts and elevated snRNAs in the nucleus after XPO1 inhibition in the SF3B1 mutant cell line. Global RNA expression and splicing analysis revealed increased alternative splicing in SF3B1 mutant cells after XPO1 inhibition. These results suggest that the preferential sensitivity of SF3B1 mutant cells to nuclear export inhibition arises through increased nuclear retention of spliceosomal snRNAs and select mRNAs that results in perturbation of apoptotic pathways. Despite the promising efficacy of XPO1 inhibition in SF3B1-mutated MDS, dose escalation is limited by toxicity. In order to identify novel drug combination targets with lower XPO1 inhibitor doses, we employed whole genome CRISPR screens in two acute myeloid leukemia (AML) cell lines treated with XPO1 inhibitor. We identified two drug targets that greatly synergized with eltanexor specifically in the SF3B1 mutant cell lines: venetoclax (a BCL2 inhibitor), and A1331852 (a BCL-XL inhibitor). In addition, BH3 profiling demonstrated increased priming of the BCL2 and BCL-XL in SF3B1 mutant cells. We further validated these combinations in vivo using competitive transplant assays in Sf3b1 K700E conditional knock-in mice. The combination of eltanexor with venetoclax and eltanexor with A1331852 showed a significant decrease in the Sf3b1-mutant burden in the peripheral blood and bone marrow progenitor compartments, suggesting a preferential sensitivity of the combinations for SF3B1 mutant cells. Although A1331852 exhibited similar results to venetoclax, there was increased weight loss and decrease in hemoglobin associated with BCLXL inhibition. In conclusion, our study provides insight on the mechanisms underlying the heightened sensitivity of XPO1 inhibition in SF3B1-mutant MDS/AML. The identification of BCL2 and BCL-XL as synergistic targets with XPO1 inhibitors, validated by in vivo testing, BH3 profiling, and RNA sequencing, highlights the potential for therapeutic combinations. Specifically, the combination of eltanexor and venetoclax could be a promising SF3B1-specific therapy. Citation Format: Sana Chaudhry, Felipe Beckedorff, Shaista Shabbir Jasdanwala, Tulasigeri M Totiger, Maurizio Affer, Nidhi Hariramani, Olivia Tonini, Stephan Noudali, Alexandra Chirino, Alyssa Cornista, Skye Montoya, Daniel Bilbao, Jumana Afaghani, Jose Antonio Rodríguez, Shruti Bhatt, Eric Wang, Justin Taylor. Altered RNA Export Sensitizes to Nuclear Export Inhibition in SF3B1 Mutant MDS [abstract]. In: Proceedings of the Blood Cancer Discovery Symposium; 2024 Mar 4-6; Boston, MA. Philadelphia (PA): AACR; Blood Cancer Discov 2024;5(2_Suppl):Abstract nr P26.

Ectopic expression of the transcription factor ONECUT3 drives a complex karyotype in myelodysplastic syndromes.

Chromosomal instability is a prominent biological feature of myelodysplastic syndromes (MDS), with over 50% of patients with MDS harboring chromosomal abnormalities or a complex karyotype (CK). Despite this observation, the mechanisms underlying mitotic and chromosomal defects in MDS remain elusive. In this study, we identified ectopic expression of the transcription factor ONECUT3, which is associated with CKs and poorer survival outcomes in MDS. ONECUT3-overexpressing cell models exhibited enrichment of several notable pathways, including signatures of sister chromosome exchange separation and mitotic nuclear division with the upregulation of INCENP and CDCA8 genes. Notably, dysregulation of chromosome passenger complex (CPC) accumulation, besides the cell equator and midbody, during mitotic phases consequently caused cytokinesis failure and defective chromosome segregation. Mechanistically, the homeobox (HOX) domain of ONECUT3, serving as the DNA binding domain, occupied the unique genomic regions of INCENP and CDCA8 and transcriptionally activated these 2 genes. We identified a lead compound, C5484617, that functionally targeted the HOX domain of ONECUT3, inhibiting its transcriptional activity on downstream genes, and synergistically resensitized MDS cells to hypomethylating agents. This study revealed that ONECUT3 promoted chromosomal instability by transcriptional activation of INCENP and CDCA8, suggesting potential prognostic and therapeutic roles for targeting high-risk MDS patients with a CK.

Haploidentical Transplant with Post-Transplant Cyclophosphamide for Acute Myeloid Leukaemia and Myelodysplastic Syndromes Patients: The Role of Previous Lines of Therapy.

Allogeneic haematopoietic stem-cell transplant is an option, potentially curative, for high-risk acute myeloid leukaemia (AML) and myelodysplastic syndrome (MDS) patients. Post-transplant cyclophosphamide administration allows for the selection of haploidentical donors in patients who are eligible for the procedure but do not have a fully matched donor since it can overcome the HLA barrier. There is still an active debate on whether intensifying the conditioning regimen is necessary with haploidentical donors when peripheral blood stem cells are used as the graft source. Herein, we report our decennial experience of haploidentical stem-cell transplant using peripheral blood stem cells (haplo-PBSC) at King's College Hospital. The primary objective was to evaluate overall survival (OS) following haplo-PBSC. Secondary objectives were total OS for patients with less than two previous lines of therapy, OS according to cytomegalovirus (CMV) reactivation, incidence of transplant-related mortality (TRM), graft-versus-host disease (GVHD) and GVHD-relapse-free survival (GRFS). One-year and three-year total OS were 62% and 43%, respectively, with a median OS of 22 months. One-year and three-year OS for patients with ≤2 and those with >2 previous lines of therapy were 72% and 55%, and 60% and 22%, respectively (p-value=0.04). The median OS in patients with >2 previous and ≤2 lines of therapy was 16 and 49 months, respectively. Cumulative incidence (CI) of relapse was 25% with a median time to relapse of 5 months (range 1 - 38 months). Haploidentical haematopoietic stem-cell transplant is potentially curative in chemosensitive AML and MDS and offers a high rate of prolonged remission. Our cohort further confirms the role of consolidative haploidentical transplant in patients in complete remission and highlights that patients with heavily pre-treated disease may not benefit from this strategy.

Efficacy and safety of coadministration of venetoclax and anti-fungal agents under therapeutic drug monitor in unfit acute myeloid leukemia and high-risk myelodysplastic syndrome with neutropenia: a single-center retrospective study

Unfit acute myeloid leukemia and high-risk myelodysplastic syndrome patients with prolonged neutropenia demand coadministration of venetoclax and azoles. However, venetoclax dosing under drug–drug interaction with azoles remains controversial. Therapeutic drug monitoring (TDM) is expected to guide drug dosage adjustments. We retrospectively enrolled 17 patients under this coadministration and TDM. Venetoclax dosages were interfered when inappropriate drug concentrations appeared. The primary endpoints were objective response and adverse events. Venetoclax concentration outliers were more frequently evaluated before than after dose adjustment (Cmax 60.87% vs. 0.00%, p < .0001). MRD negativity rate was higher in patients staying within reference range than those having outliers (90.91% vs. 33.33%, p = .028). Objective response rate was 100%. Hematologic adverse events included neutropenia (93.3%), febrile neutropenia (53.3%), and thrombocytopenia (81.3%). Median time to neutropenia and thrombocytopenia recovery was 20 (14–32) and 16.5 (6–34) days, respectively. No invasive fungal and other life-threatening infections were observed.

Reconsidering the Significance of Blast Cut-Offs in Differentiating between MDS and AML Biology

Background The diagnosis of and distinction between acute myeloid leukemia (AML) and high-risk myelodysplastic syndrome (MDS) have long been based on blast counts, with the presence of ≥20% myeloblasts in marrow or peripheral blood required to define AML in World Health Organization classification. Until 2001, blast counts greater than 30% had been used to diagnose AML by the original French-American-British classification system. However, the 2022 International Consensus Classification proposed a new combined category of MDS/AML with 10-19% blasts. Here we report the real-world treatment pattern and outcomes of AML and high-risk MDS patients at an academic institution in the United States, with specific attention to the blast burden at initial disease diagnosis to validate accuracy and limitation of this new proposed change. Methods This is a retrospective study conducted at UCLA Health encompassing all diagnoses of AML and MDS made at academic campus and community practices. We evaluated adult patients with a diagnosis with either AML or MDS from 1/1/2016-7/31/2022. For patients with more than one bone marrow biopsy on record, we recognized the date of diagnosis of MDS or AML with a blast burden ≥ 10% by immunohistochemistry or flow cytometry as the first bone marrow biopsy. In light of the changing diagnostic definitions, we analyzed patients by cohorts of MDS/AML with 10-19% blasts, AML low-blast with 20-29% blasts, and AML high-blast ≥ 30% blasts. Survival analysis by blast count at diagnosis was calculated by Kaplan-Meier estimates. A Multivariable Cox proportional hazard model was used to model survival outcomes by blast cohort, ELN risk 2022, response to first treatment, and receipt of allogeneic hematopoietic cell transplantation (HCT). Results There were 422 patients at UCLA Health with a diagnosis of AML or MDS included in our analysis with blast burden ≥ 10%. Patient demographics are shown in Table 1. Median age at diagnosis for MDS/AML, AML low-blast and AML high-blast cohorts is 67, 66 and 64 respectively (p=0.02). Thirty two (66.7%) patients in MDS/AML cohort received non-intensive first line treatment, whereas 202 (67.8%) AML high-blast patients received intensive first treatment. For AML low-blast patients, 37 (48.7%) received intensive treatment, and 29 (38.2%) received non-intensive treatment. More patients with AML (either low- or high-blast) underwent allogeneic HCT compared to MDS/AML patients. By Kaplain Meier analysis (KM) using blast counts as the sole predictor (Figure 1), no significant difference in OS when following patients for up to five years from diagnosis (p=0.0985) was seen. The p-value for two-way KM comparisons for MDS/AML vs. AML low-blast is 0.9682, and for AML low-blast vs. AML high-blast is 0.112. By multivariable analysis, ELN Risk 2022 (p&amp;lt;.0001), allogeneic HCT (p&amp;lt;.0001), and Complete Response to initial treatment (p&amp;lt;.0001) were predictive of OS, but blast percentages were not (p=0.56). Conclusion In our study, we found similar survival outcomes in high-risk MDS and AML patients regardless of initial blast counts at diagnosis. Though not statistically significant, MDS/AML and AML with low-blast burden appear to share more similar outcomes. This could be due to increased secondary AML seen in the low-blast cohort, and implies potentially different disease biology between high blast burden AML and AML with dysplastic changes. With this observation, we emphasize caution on simply using ICC 2022 to apply traditional AML therapy to the new MDS/AML category. Both WHO and ICC classification in 2022 reflects the increasing potential of molecular profiling to subtype these diseases, which will be the future direction. Rather than moving the blast count cutoff between AML and MDS, it is more critical to emphasize inclusion of high-risk MDS patients on all AML clinical trials and perhaps the converse for low blast burden AML with dysplastic changes, which might allow better understanding of response to therapy and disease biology.

A Patient-Centered Programmatic Approach for Higher-Risk Myelodysplastic Syndromes (HR-MDS) in the US Community Oncology Setting

Introduction: Prompt diagnosis and treatment are critical for patients with higher-risk myelodysplastic syndromes (HR-MDS) given the high likelihood of progression to leukemia and adverse clinical outcomes. However, pre-diagnosis dynamics can contribute to delays in diagnosis, genetic testing, and treatment initiation, especially among patients receiving care in the community oncology setting. A patient-centered program has been designed and is proposed to be executed in 4 phases: understanding adherence to guideline-concordant care for HR-MDS patients; gaining perspectives to contextualize the patient experience; and implementing a program that can monitor the process for improving patient outcomes (Figure 1). The objectives of this study are to evaluate and address the gaps and disparities of care in the diagnostic and treatment journey of patients with HR-MDS treated in a community oncology setting in order to provide an evidence-based understanding of the patient characteristics and journey to testing, diagnosis, and treatment (Phase 1 of the program). Methods: This is a retrospective chart review including patients treated in the community oncology network and identified in the Integra PrecisionQ deidentified database. Patients were identified as diagnosed with HR-MDS between January 1, 2014 and June 30, 2022, using a combination of ICD codes and receipt of hypomethylating agents in line with National Comprehensive Cancer Network guidelines as their first treatment. Eligible patients had at least 3 months of follow-up and at least 6 months of look-back prior to HR-MDS diagnosis. Signs and symptoms such as fatigue, weight loss, bruise, chills, night sweats, anemia, thrombocytopenia, and neutropenia that initiated the HR-MDS diagnosis journey were collected by manual curation. Results: A total of 350 patients aged 18 years or older diagnosed with HR-MDS over the study period were selected. The majority of patients included in this sample were White (82.6%) and male (59.4%) (Table 1). More than 50% of the 350 patients were ≥75 years old at diagnosis and most of them (91%) were diagnosed by a hematologist/oncologist in an outpatient setting. The median time from first sign/symptom to bone marrow biopsy and treatment initiation were 19.3 months (interquartile range [IQR] 8.9, 44.3) and 22 months (IQR 11.4, 45.8), respectively. Of the 350 patients included in the study, 342 (97.7%) had at least 1 sign or symptom leading to HR-MDS diagnosis, with the majority of patients presenting with anemia (77.2%), followed by thrombocytopenia (66.4%), fatigue (64.3%), and neutropenia (43.3%). International Prognostic Scoring System (IPSS) scores were not documented for nearly half (43.7%) of the patients included in this chart review. Conclusions: This initial analysis highlights several challenges in the HR-MDS patient care journey, including long time intervals elapsed between first sign/symptom and bone marrow biopsy, leading to further treatment, accompanied by a relatively high absence of IPSS score documentation. These findings suggest several potential opportunities to optimize patient care, such as shortening the time from symptoms to diagnosis and time from diagnosis to treatment, utilization and documentation of IPSS score, and prompt treatment initiation. Ultimately, this program aims to utilize this Phase 1 data to identify the gaps in care and to formulate quality measures to optimize care and facilitate timely diagnosis and appropriate treatment initiation among HR-MDS patients.

Encouraging Efficacy Observed in Bexmab Study: A Phase 1/2 Study to Assess Safety and Efficacy of Bexmarilimab in Combination with Standard of Care in Myeloid Malignancies

Background Clever-1 (common lymphatic endothelial and vascular endothelial receptor-1) constitutes a novel macrophage checkpoint. The receptor contributes to immune tolerance by antigen clearing and T cell inhibition. In multiple models, tumor growth is significantly reduced when Clever-1 function is inhibited. Expression of Clever-1 on bone marrow (BM) cells is a prognostic factor for poor outcome in acute myeloid leukemia (AML) and suppression of Clever-1 signaling inhibits leukemia cell growth. Bexmarilimab (BEX), a humanized IgG4 monoclonal antibody, binds Clever-1 resulting in increased antigen presentation, secretion of proinflammatory cytokines and activation of T cells. Clever-1 is highly expressed on leukemic blasts and monocytes of AML and myelodysplastic syndrome (MDS) patients. Treatment of AML bone marrow cells with BEX alone or in combination with azacitidine/venetoclax results in enhanced antigen presentation capacity and increased activation markers on effector T cells with synergistic effect on cell death. Also, BEX treatment alone lowers blast metabolic fitness via interference with mitochondrial oxidation. The ongoing BEXMAB clinical study investigates safety and efficacy of BEX combined with standard of care (SoC) in patients with myeloid malignancies (NCT05428969). Method This is a Ph1/2 study, investigating BEX combined with azacitidine (doublet) in patients with higher risk MDS frontline or hypomethylating agent (HMA)-failed, and relapsed/refractory (r/r) AML patients. BEX is dosed Q1W in 28-day cycles until disease progression or intolerable toxicity. SoC azacitidine is administered as per label. During Ph1, BEX doses were escalated from 1.0 mg/kg to 6.0 mg/kg (Bayesian optimal interval [BOIN] design). BM was analyzed at the end of Cycle 1 and 3 followed by every three cycles. Ph2 will start with a dose optimization per malignancy followed by a dose expansion for efficacy evaluation (2-Stage design). Results Here we report data from the dose finding Ph1 of the doublet. As of 25 July 2023, 22 patients have been enrolled in the doublet (MDS n=5; MDS HMA failed n=5; r/r AML n=12). Baseline characteristics are shown in Table 1. 8/10 MDS/MDS HMA-failed patients were of high to very high risk based on rIPSS; of the r/r AML 7/12 patients had adverse risk based on ELN 2017. The median number of prior therapies for the MDS HMA-failed patients was 1 (range 1-2). The median number of prior therapies for the r/r AML patients was 2 (range 1-4) with all patients having failed prior HMA-containing therapies and 7/12 having received prior HMA plus venetoclax. The majority of observed adverse events (AE) were Grade 1-2 and no dose limiting toxicities have been reported. As of 25 July 2023, a total of 10 BEX related AEs have been reported (8% of all treatment emergent AEs) with four of these events of ≥ Grade 3, two being immune related (capillary leak syndrome and hemophagocytic lymphohistiocytosis). Sustained target engagement of soluble Clever-1 of up to 75% compared to baseline was seen at all tested dose levels in patient blood. Activity of BEX in patient BM was demonstrated using receptor binding assays with BEX treatment resulting in decreased blast Clever-1 expression at all dose levels of the doublet cohort. Increased immune activation as measured using HLA expression and T/NK cell numbers in patient BM was observed after BEX treatment across indications. Up to 2-3-fold increase of CD8 T and NK cells in the BM of BEX treated patients was observed. Preliminary efficacy shows objective responses in 8/15 evaluable patients across all tested BEX doses. Four were observed in patients with prior HMA-failure and four patients stayed on treatment &amp;gt; 6 months. Clinical activity for frontline MDS was seen as one complete remission (CR), marrow CR (mCR) and hematologic improvement for platelets (HI-P); for MDS with HMA failure as one CR, mCR and partial remission (PR); for r/r AML as two incomplete CRs (CRi). Based on accumulating data, responses are observed between end Cycle 1 and end Cycle 4 for all BEX doses. Conclusion Combining BEX plus azacitidine is well-tolerated and shows efficacy across indications. Additional clinical and pharmacodynamic data of the completed Ph1 of the study will be presented during the meeting. Ph2 of BEX plus azacitidine will open in the 2 nd half of 2023 in HMA-failed r/r AML and/or higher risk MDS patients.

Ultra-Low-Dose of Decitabine with Venetoclax As Induction and Consolidation Therapy for Elderly or Frail Newly Diagnosed Acute Myeloid Leukemia and High Risk Myelodysplastic Syndrome Patients

Background: Venetoclax with hypomethylating agents is a new standard of care for newly diagnosed (ND) patients with acute myeloid leukemia (AML) who are 75 years or older, or unfit for intensive chemotherapy. Pharmacodynamic studies have suggested superiority of the longer 10-day regimen of decitabine which has shown promising results in high-risk AML in phase 2 trials. We hypothesized that venetoclax with 10-day decitabine may be effective in ND and secondly AML/MDS, particularly for high-risk subgroups. Methods: We retrospectively analyzed 45 patients with ND AML, secondary AML (sAML), or high-risk MDS who was older than 60 years or unfit for intensive chemotherapy due to frail / due to the COVID-19 pandemic. Patients were required adequate end-organ function. Patients received decitabine (6mg/m2 IV for 10-days) with oral venetoclax (400mg daily for 3 weeks (D10+VEN)) for induction, followed by the same chemo-free regimen for consolidation if patients responsed to induction therapy. The primary efficacy endpoint was overall response rate (ORR). The second endpoint was overall survival (OS) and progress free survival (PFS). Findings: Between January, 2020 and July , 2023, 45 patients were treated with this regimen, 31 (68.9%) had ND AML, 8 patients (17.8%) had untreated sAML, 6 patients (13.3%) had untreated high-risk MDS. The median age was 65 years (IQR, 59-69) and 26(57.8%) patients had ECOG performance status of 3 or higher. The ORR among all patients was 82.2% and in disease subgroups were: ND AML, 87.1% (27/31) (95% CI 79, 94); untreated sAML, 75% (6/8); untreated high-risk MDS, 66.7%(4/6). According 2022 ELN risk classification by genetics, the ORR in favorable risk patients was 87.5%(7/8), intermediate risk patients was 100%(12/12), adverse risk patients was 72%(18/25). The most common treatment-emergent adverse events included infections with grade 3/4 neutropenia (n=36, 80%) and febrile neutropenia (n=7, 15.6%). There were 2 grade 5 adverse events including one infections with Enterobacter cloacae Bacteremias combined with heart failure because of the shortage of Blood product transfusion during the COVID-19 pandemic, and one case of intracranial hemorrhage related to prolonged grade 3/4 thrombocytopenia. The one year OS of all patients was 71.9%(23/32), and in favorable risk patients was 83.3% (5/6), intermediate risk patients was 72.7%(8/11), adverse risk patients was 73.3%(11/15). The two-year OS of all patients was 58.3%(7/12). Conclusion: Ultra-low-dose of ten-day decitabine with venetoclax as induction and consolidation chemo-free therapy in elderly or frail newly diagnosed acute myeloid leukemia and high risk myelodysplastic syndrome result in high overall response rate and high 1-year overall survivial.

Metabolic Syndrome Among Patients with Myelodysplastic Syndrome: A Population Analysis

Introduction: Metabolic syndrome (MS) comprises a cluster of cardiovascular risk factors, including central obesity, dysglycemia, elevated blood pressure (BP), increased triglyceride levels (HyperTG), and low HDL cholesterol levels. Epidemiologic and clinical data suggest that MS may be an important etiologic factor in the progression of certain cancer types. These studies have excluded patients with myelodysplastic syndromes (MDS), but MS may be relevant in these patients owing to the link between cardiovascular disease and MDS derived from clonal hematopoiesis. We conducted a population-based analysis to define the prevalence of MS and its components among patients with MDS and explore the effect of MS on MDS outcomes. Methods: We identified patients aged 66 and older diagnosed with MDS between 2007 and 2017 using the SEER-Medicare database. Preexisting MS was identified using ICD-9/10 codes in claims from at least 12 months before MDS diagnosis. MS was defined as the presence of 3 or more of the 5 MS components. MDS histologic risk was defined based on ICD-O-3 morphology codes. Transfusion dependence, defined as 2 or more transfusions within 8 weeks of MDS diagnosis date, and therapy with hypomethylating agents (HMA), lenalidomide and erythropoietin stimulating agents (ESA) were defined from HCPCS codes and prescription records. Other variables defined included age, sex, race/ethnicity, rurality (using RUCC codes), marital status, and socioeconomic status [SES] (using the Yost index). Descriptive statistics were used to define the frequency of MS and its components. MDS outcomes of interest were transformation to acute myeloid leukemia (AML), defined from ICD-9/10 codes for AML, and overall survival (OS), defined as the time between MDS diagnosis and death from any cause. Cox proportional hazards regression was used to determine the association between MS and AML transformation and OS, through adjusted hazard ratios (HR). Results: A total of 15,227 cases diagnosed with MDS between 2007 and 2017 were analyzed, including 3,402 (22.3%) with baseline MS. High BP was present in 72.2%, HyperTG in 47.8%, dysglycemia in 35.5%, central obesity in 4.6% and 0.5% had low HDL cholesterol. The prevalence of MS and the distribution of its components did not significantly differ based on MDS histologic risk (Table 1). The prevalence of hyperTG was notably higher in patients with MDS, especially in the high histologic risk category (50.4%). Compared to other MDS patients, those with preexisting MS were predominantly male (55.5% vs 53.3%, p=0.03) of non-White race (6.7% vs 4.8% non-Hispanic Black, p&amp;lt;0.01, and 2.1% vs 1.5% Hispanic, p&amp;lt;0.01), from urban/metropolitan areas (87.7% vs 86%, p=0.01) and lower SES quintiles 1 and 2 (34.2% vs 31.5%, p&amp;lt;0.01). In a model adjusting for age, sex, race/ethnicity, rurality, marital status, SES, MDS risk, transfusion dependence and MDS therapies (HMA, lenalidomide and ESA), baseline MS at the time of MDS diagnosis was not associated with a significant effect on the risk of AML transformation (HR=1.0, 95%CI 0.9-1.2) or the risk of death from any cause (HR=1.0, 95%CI 0.9-1.1) (Table 2). In models assessing the effect of MS subcomponents on MDS outcomes, high BP (HR=1.0, 95CI% 1.0-1.1) and obesity (HR=1.1, 95CI% 1.0-1.2) were associated with an increased risk of mortality. Obesity was also associated with an increased risk of transformation to AML (HR=1.3, 95CI% 1.0-1.6). Conclusions: The overall prevalence of MS among patients with MDS appears similar to that reported in the general population and does not differ based on the histologic risk category. The observed prevalence of HyperTG was higher than expected, particularly in high-risk MDS patients. Older males of non-White race from urban/metropolitan areas of lower SES are more likely affected across all groups. Though preexisting MS is present in an important proportion of MDS patients, it was not significantly associated with an increased risk of mortality or AML transformation after adjusting for confounders. Obesity was associated with higher mortality and linked to increased transformation to AML. Given recent data suggesting that statins may improve survival and decrease AML transformation in MDS, future studies should investigate the potential association between other metabolic parameters and MDS outcomes.

Prognostic Value of Measurable Residual Disease in High-Risk Myelodysplastic Syndromes with Intensive Chemotherapy Treatment: Analysis of HOVON-SAKK Studies

Diagnosis of myelodysplastic syndromes (MDS) and accurate risk assessment to tailor treatment remains challenging. High-risk MDS (hrMDS) patients who are fit enough may benefit from intensive chemotherapy followed by post-remission consolidation. The HOVON-SAKK (HO) acute myeloid leukemia (AML) trials, designed to test novel drug combinations with an intensive treatment regimen, included hrMDS patients (RAEB and RAEB-T). Since these HO-trials have been executed with large patient cohorts for many years, they offer the unique possibility to study the outcome, risk classification, and relevance of measurable residual disease (MRD) in hrMDS. A pooled database is available from HOVON-SAKK of patients who were treated with intensive chemotherapy (studies containing MDS patients with IPSS ≥ 1.5 HO42A, HO81, HO92, HO102, and IPSS-R &amp;gt; 4.5 HO103, HO132). The database contained 3268 patients; 11% (364/3268) were hrMDS scored according to IPSS and IPPS-R. Three-year overall survival (OS) for hrMDS was 32% (standard error; SE 2%) compared to AML 46% (SE 1%). In total, 1074 AML and 75 hrMDS had reached complete remission (CR/CRi) and received a second induction cycle (C2). MRD after C2 based on multiparameter flow cytometry (Cloos et al., 2018, J. Vis.) with a cut-off of ≥0.1% for MRD positivity was assessed to evaluate the MRD status. We observed a trend of a higher MRD positivity rate for MDS compared to AML patients (MDS vs. AML: 32% (23/73) vs. 22% (232/1064), P = 0.055). Kaplan-Meier OS analysis showed a significant prognostic value of MRD in MDS, but not in the cumulative incidence of relapse (CIR) (log-rank test 0.011, Gray's test P = 0.124). Since the MDS classification has been changed, we re-classified MDS based on the ICC 2022 classification into AML, AML/MDS, and MDS. We reclassified 3035 patients at diagnosis, including 2605 AML, 258 MDS/AML, and 172 MDS. The three-year OS was 47% (SE 1%) for AML, 29% (SE 3%) for MDS/AML, and 33% (SE 4%) for MDS. After C2, 2215 patients had reached CR/CRi. A total of 1074 patients containing 984 AML, 57 AML/MDS, and 33 high-risk MDS patients with CR/CRi after C2, with a suitable bone marrow sample, were included in the MRD analysis. Most patients were treated according to HO132 (40-48%). As expected, MDS patients were older (median age, range; 60, 32-74), had lower bone marrow blast counts, and were predominantly of adverse risk. A trend of a higher proportion of MRD positivity after C2 was observed in the MDS group (33%; 11/33) as compared to AML (22%; 215/984) or MDS/AML (18%; 10/57). Three-year OS was 61% for AML (SE 1.6%), 42% (SE 6.6%), and 49% (8.7%) for AML/MDS and MDS, respectively (Figure 1A). Kaplan-Meier OS analysis and CIR showed a significant prognostic value of MRD for MDS (log-rank test P&amp;lt;0.001, Gray's test P = 0.015) and AML ( P&amp;lt;0.001; P&amp;lt;0.001) but not for MDS/AML patients ( P = 0.5, P = 0.342)(Figure 1B). Remarkably, the three-year OS of MRDpos in MDS was 18% (SE 12%) compared to MRDpos in AML 40% (SE 16%). The limitation of this study is the relatively small number of MDS patients according to the new ICC 2022 guidelines. In summary, MRD detection in the HOVON-SAKK trials shows the potential of MRD as a prognostic value in MDS patients treated on intensive induction regimens with a clinically validated and standardized assay.

Venetoclax and Azacytidine Treatment for High Risk Myelodysplastic Syndromes and Chronic Myelomonocytic Leukemia As a Bridge Therapy to Transplant. a GESMD Study

Introduction Allogeneic hematopoietic cell transplantation (alloHCT) is the only potentially curative treatment for myelodysplastic syndromes (MDS) and chronic myelomonocytic leukemia (CMML). Most common approach to bridge higher-risk MDS to alloHCT is to reduce tumor burden before alloHCT with azacytidine (AZA). Currently with this strategy less than 50% of patients achieve overall response rate (ORR) and less than 20% complete response (CR). Moreover, it is associated with a considerable rate of drop outs (approximately 50%) due to progression disease and mortality prior to alloHCT. Therefore, we need more effective treatments with faster and higher responses to facilitate more patients to undergo alloHCT. Venetoclax with AZA (VEN/AZA) is being investigated mostly in unfit MDS patients, it has shown higher ORR and early responses. Recently, a study suggested promising activity in 13 high-risk MDS patients who received VEN/AZA and proceeded to alloHCT (Komrokji et al, BCJ, 2022). The objective of our study is to analyze the feasibility, toxicity, and efficacy of VEN/AZA treatment in MDS and CMML patients who are intended to undergo alloHCT. Methods This is a retrospective multicenter study that includes high-risk MDS and CMML patients treated with VEN/AZA who are intended to undergo alloHCT. The response rate was assessed according to the IWG 2006, IWG 2023, ELN 2022. Savona criteria were used in CMML. Results A total of 23 patients were included, with a median age of 61 years (41-74), including 19 MDS and 4 CMML patients. Eight patients received VEN/AZA in a relapsed/refractory (R/R) setting, while 15 in first line (1L). Most patients received a 14-day scheme of VEN (n=16). The administration of VEN/AZA and other characteristics are described in Table 1. Grade 3/4 cytopenias were frequent (83% neutropenia 65% thrombocytopenia, 59% anemia), 17% experienced febrile neutropenia and 17% required hospitalization. G-CSF was used in 44% of patients, antifungal prophylaxis in 43%, and cycle delays due to cytopenias happened in half of them (47%). Thirty-day mortality was 0%, and one patient (4%) died within the first 60 days due to disease progression. The response rate following IWG 2023 criteria was: 7 CR (30%), 6 CR with limited count recovery (CR L, 26%), 4 CR with partial hematologic recovery (CRh, 17%), 3 partial remissions (PR, 13%), 1 hematologic improvement (HI, 4%), and 2 no response (9%). The ORR was 91.3% (21/23), and the rate of composite complete responses (CRc) including CR, CR L and CRh was 73.9% (17/23) . These responses occurred rapidly, all patients achieved the first response in 1 cycle and the median to best response was 1 cycle (range 1-3). In R/R patients the ORR was 87% and the CRc was 62%. Using the ELN 2022 versus IWG 2023 response criteria results in similar CRc, higher rate of CR (34% vs 22%) and lower ORR (86 vs 91%). The median follow-up since the start of treatment was 13.6 months (95% CI: 5.2-21). The 2-year overall survival (OS) was 63% (95% CI ± 24%). Currently, there are 2 patients awaiting alloHCT. Among the 21 evaluable patients, 19 underwent alloHCT, resulting in a alloHCT rate of 91%. The 2 patients who were not transplanted included one CMML patient with disease progression prior alloHCT and one refractory MDS. AlloHCT was performed with a median of 3 prior cycles (range: 1-9), and the median time from the start of VEN/AZA to transplantation was 4 months (range: 2.5-10). One patient who did not respond to VEN/AZA was treated with chemotherapy prior alloHCT achieving CR. Two patients progressed before alloHCT, one achieved CR after chemotherapy and the other one has received a sequential alloSCT. The two-year post-transplant OS was 67% (95% CI ± 28%) (Figure 1). Four patients relapsed after alloHCT, resulting in a two-year cumulative incidence of relapse (CIR) of 37% (95% CI ± 28%). One of these patients was treated with VEN/AZA post-transplant and he is currently in CR for 1.5 years. 2-year transplant-related mortality was 6% (95% CI ± 12%). Conclusion Treatment with VEN/AZA as a bridge to alloHCT in MDS and CMML patients is feasible with a high rate of patients undergoing alloHCT. It provides high and quick responses, even in R/R patients, with low treatment-related toxicity. Funding This study was supported by grants from the Institute of Health Carlos III (ISCIII), with grant numbers PI19/01476 and PI22/01660, co-financed by the European Union. Additional support was provided by Emili-Letang (HCPB).

Combination of Decitabine and Etoposide Is Highly Effective in Treating p53-Mutated MDS/AML Via Activating Notch Signaling

The elderly MDS/AML patients, especially those with TP53 mutations, remain very difficult to treat and resistant to chemotherapy. A total of 105 elderly (age above 60 years) high risk MDS (n = 84, IPSS-R score &amp;gt; 4.5) or AML-MRC (n = 21) patients' records were collected from three medical centers across China and retrospectively analyzed. Decitabine and low dose etoposide was found to be superior to standard decitabine alone in MDS/AML patients with higher ORR (70.0% vs 52.7%) after two cycles of treatment, the longer median durations of ORR (24.0 months vs 12 months) and CR (38.0 months vs 24.0 months), and longer event-free survival (13 months vs 9 months, p = 0.023), without significant improvement in overall survival (20 months vs 15 months, p = 0.059). Other than the TP53 mutation, no other gene mutation (including NRAS, DNMT3A, TET2, EZH2, ASXL1, RUNX1) in the D+E group could reliably predict OS and EFS when compared to wild type phenotype. Patients with TP53 mutations showed higher response rate after two cycles of D+E therapy and had prolonged overall survival (Mutation vs WT: 31 months vs 9 months, p=0.012) and event-free survival (Mutation vs WT: 24 months vs 5 months, p = 0.022) compared with p53 wild type patients in D+E group from multivariate survival analyses. P53 mutated patients receiving D+E treatment also had significantly improved OS (31 months vs 12 months, p = 0.00) and EFS (24 months vs 8 months, p = 0.00) compared to patients receiving decitabine treatment. Moreover, we found decitabine and etoposide greatly reduced TP53 mutant AML tumor burden in the NSG mice xenografts (tumor burden: 92% reduction in p53-null xenograft mice, 65% reduction in p53-wild-type xenograft mice on day 20 after leukemia cells administration, p &amp;lt; 0.0001). It was found that TP53 mutant cells and p53 gene-editing MOLM13 cells showed terminal neutrophil differentiation in the combo of decitabine and etoposide, demonstrating the expected changes in cell-surface CD11b expression and neutrophil functional assays such as phagocytosis. Combo of decitabine and etoposide showed much higher percentage of differentiation marker expression compared to single drug decitabine or etoposide treatment. However, neither the p53 gene-edited THP-1 cells nor the TP53 wild type cell lines displayed markers of terminal differentiation, such as elevated CD11b expression or phagocytosis. Furthermore, the percentage of CD11b-positive cells increased significantly in p53-mutated primary cells while insignificantly in TP53 wild type cells. Decitabine and etoposide induced significant differentiation thus killing p53 mutated myeloid tumor cells and primary patients' cells in vitro. We also uncovered the underlying mechanism that why D+E could induce significant differentiation in TP53 Mutant while not in TP53 wild type myeloid tumors. Notch1 signaling pathway was activated after D+E treatment in TP53 Mutant myeloid tumors, which was consistently correlated with drug-induced myeloid differentiation. Notch1 knockout or Notch inhibitor incubation abrogated drug induced differentiation in TP53 Mutant myeloid tumors. The activation of the Notch1 signaling pathway has been observed to induce disease regression and decrease leukemia stem cells in AML mice as well as significant apoptosis in the AML patient sample. We also found D+E could upregulate transcription factor transcripts such as ETS1, ETS2, which could bind specifically to PSEN1 (PS1) promoter and activate its transcription directly. PS1 represent catalytic subunit of γ-secretase complexes and is responsible for Notch recognition. While in TP53 wild type AML cells, p53 might interact with p300. p300 acts as a coactivator of Ets1 and Ets2, competition for binding to p300 with p53 may confront p300 recruitment and repress ETS transcription activation directly, which might exert its effect on PS1 repression, thus inhibiting γ-secretase complex activity. In short, integrated p53 could repress PSEN1 transcription thus interfering gamma secretase complex activity, Notch recognition and cleavage as well as abrogating drug induced Notch activation and myeloid differentiation, which could be achieved in p53 mutated state. Combination of decitabine and etoposide regimen is also relatively safe and tolerable in elderly patients, which may open up a new path of therapy in the p53 mutated AML/MDS.

Venetoclax Plus Azacitidine Versus Azacitidine Alone As Post-Transplant Maintenance Treatment in High-Risk AML and MDS

Background: Disease recurrence is the main cause of transplantation failure for high-risk acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Exploring innovative approaches to prevent relapse in AML and MDS after Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is in urgent need. Both bcl-2 inhibitor venetoclax (VEN) and azacitidine (AZA) possess significant antitumor activity effects against myeloid neoplasms. The efficacy and safety of AZA alone as maintenance therapy in the posttransplant setting have been reported but the results are controversial. The combination of VEN and AZA has resulted in high response rates in treating AML patients. We conducted a prospective clinical trial to compare the utility and safety of the combination of VEN and AZA (VEN/AZA) and AZA alone as maintenance treatment in high-risk AML and MDS in the post-transplant setting. Methods: This is a prospective, multicenter, randomized clinical trial. Patients with AML or MDS who were evaluated as high risk of relapse and underwent allo-HSCT were randomly assigned into VEN/AZA group and AZA group by gender, age, and disease type based on the central randomization system. AZA was administered by subcutaneous injection for 5 days at a dose of 50 mg/m2. VEN was administrated at the dosage of 200 mg daily from day 1 to day 7. VEN/AZA maintenance therapy regimen comprised AZA and VEN used alternately every month. AZA alone group was administrated AZA every 2 months. Maintenance treatment lasted at least 1 year after transplantation unless relapse occurred. The primary endpoint of the study included overall survival (OS), disease-free survival (DFS), and cumulative incidence of relapse (CIR). The second endpoints included adverse events (AEs), nonrelapse mortality (NRM), incidence of acute graft versus host disease (aGVHD), and chronic GVHD (cGVHD). Results: From June 2022 to June 2023, 24 patients were given the study protocol. 9 patients (6 AML, 3 MDS) received VEN/AZA maintenance and 15 (7 AML, 8 MDS) patients received only AZA maintenance. The median initial time to receive maintenance treatment was 3.67 months after transplantation. The median follow-up time was 11.30 (95%CI, 8.18-14.42) months. Only 1 patient relapsed and died 3 months after relapse on the study. The overall survival (OS) and the cumulative incidence of relapse (CIR) at 500 days were 100% vs 75.0% (95% CI, 42.59%-100%, p=0.39) and 0% vs 12.5% (95% CI, 0.48%-44.48%, p=0.39) for VEN/AZA and AZA group, respectively. The most common adverse effects (AEs) were hematological toxicities. Grade 3 or 4 hematological toxicities were observed in 5/9 (55.5%) in the VEN/AZA and 7/15 (46.7%) in the AZA group. Conclusions: Our results suggested that both VEN/AZA and AZA maintenance therapy were tolerated and the combination of VEN and AZA as maintenance therapy may be feasible and safe in the posttransplant setting to prevent relapse for high-risk AML and MDS patients.

Venetoclax+Azacytidine Followed By Modified BuCy Conditioning Regimen for High Risk or Refractory/Relapsed Acute Lymphoblastic Leukemia and High Risk Myelodysplastic Syndromes

Background:Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the only potential curable treatment for myelodysplastic syndromes (MDS) and acute lymphoblastic leukemia (ALL). However, for patients with high-risk or refractory relapsed (R/R) B-ALL with allo-HSCT, the three-year overall survival (OS) rate is only 5-10%, more worse in T-ALL. It is widely known that MDS patients in the high-risk group do not benefit from induction chemotherapy, the five-year OS rate is 23-39% when they received allo-HSCT. Nevertheless, relapse remains a significant cause of treatment failure after allo-HSCT, highlighting the urgent need for improved conditioning regimens that can improve prognosis and reduce relapse rates. Azacytidine (AZA) combined with Venetoclax (VEN), showed a synergistic anti-tumor activity against several hematological malignancies, Therefore, we explored AZA+VEN (VA) combined with modified BuCy(mBuCy) (semustine, cytarabine, busulfan, and cyclophosphamide) conditioning regimen and assessed the safety and effectiveness. Aims ：The aim of this study is to assess the safety, and effectiveness of the VA treatment regimen followed by mBuCy as conditioning regimen for high-risk or R/R ALL(NCT05809167) and high-risk MDS(NCT03256071) . Methods:Patients diagnosed with high-risk or R/R ALL or high-risk MDS (IPSS-R score), undergoing VA+mBuCy as conditioning regimen, and consolidation treatment with demethylating drugs every three months after transplantation, for a total of 8-12 cycles. Results:Patients diagnosed with high-risk or R/R ALL(n=11) or high-risk MDS (IPSS-R score)(n=8) were enrolled between January 13, 2022, and June 9, 2023. The ALL cohort comprised of 5 Ph-negative B-ALL, 2 Ph-positive B-ALL, 3 mixed phenotype leukemias (MPAL), and one T-lymphoblastic lymphoma/leukemia (T-ALL/LBL). There were 7 males and 4 females, with a median age of 33 years (17-54 years) (Table 1). Out of the eleven patients, four had previously undergone Chimeric Antigen Receptor T-Cell Immunotherapy (CAR-T) therapy, and one patient had received Blinatumomab. One patient experienced relapse, another patient was refractory, and 3 patients had extramedullary infiltration. All patients achieved morphological complete remission prior to transplantation, and 10 patients (90.9%) achieved a MRD negative remission. Additionally, all the transplantations successfully completed, with a median time to absolute neutrophil counts (ANC) recovery of 12 days (11-15 days) and platelet (PLT) recovery of 16 days (15-21 days). The median follow-up time was 6.4 months (2.4 -13.6 months), no patient experienced relapse or death, the OS and DFS are both 100%. There were no grade 3 or higher adverse events (AEs), hepatic veno-occlusive disease (VOD),and the transplant-related mortality (TRM). Four patients who developed acute graft-versus-host disease (aGVHD) post-transplantation, all cases involved grade I/II skin aGVHD, and one of them involved grade III GI aGVHD, and no chronic graft-versus-host disease (cGVHD) were observed during the follow-up period. By the endpoint of follow-up, Cytomegalovirus (CMV) activation was 45.4% (5/11) and Epstein-Barr virus (EBV) activation was 27.3% (3/11). The MDS cohort consisted of 7 cases of MDS-EB-I, 1 case of MDS-EB-II. There were 5 males and 3 females, with a median age of 42 years (23-57 years)(Table 2). Two patients received chemotherapy before transplantation, and the other six patients directly received allo-HSCT. In MDS cohort, the median recovery time for ANC was 12 days (11-13 days) and PLT was 17.5 days (16-20 days). The median follow-up was 14.3 months (1.2-18.3 months), no patient had relapsed or died, both OS and DFS are 100%. There were no grade 3 or higher AEs, and TRM. One patient developed VOD. Three patients developed aGVHD after transplantation, all involving degree I/II skin aGVHD, and there was one case of cGVHD during the follow-up period, where the patient developed a mild pulmonary cGVHD. By the endpoint of the follow-up, the rate of CMV activation was 37.5% (3/8) and EBV activation was 25% (2/8). Conclusion:The VA combined with the mBuCy proves to be a effective and safe conditioning regimen for high-risk ALL and MDS patients. However, more patients are needed for follow-up and validation.

Treatment of Elderly Patients with Higher Risk Myelodysplastic Syndromes with Oral Azacitidine

Background Oral formulations ofhypomethylating agents decitabine (ASTX727) and azacitidine (cc-486, AZA) were approved respectively for treatment of higher risk myelodysplastic syndromes (HR-MDS) and for maintenance of acute myeloid leukemia after remission. Management of MDS patients with oral agents is relevant to improve quality of life. Oral-AZA has shown activity in lower risk MDS and its use is under evaluation in that setting. There are no data regarding maintenance of response achieved by subcutaneous (sc) AZA in HR-MDS cases by switching to the oral formulation. Aim The primary objective of the study was to explore the feasibility of replacing sc-AZA by its oral formulation in patients with HR-MDS in response. Maintenance or improvement of response and, as secondary objectives, patient reported outcome (PRO) and DNA methylation pattern were evaluated. Methods A monocentric, pilot phase 2 study was planned to enroll 11 subjects with confirmed diagnosis of MDS, IPSS-R higher risks, aged ≥ 65 years, in CR/CRi, PR or SD with HI after &amp;gt; 6 cycles of sc-AZA therapy (ClinicalTrial.gov NCT04806906). Patients were to receive 300 mg oral-AZA for the first 14-days of each 28-day treatment cycle until absence of benefit or disease progression. Dose of oral-AZA could be de-escalated based on toxicity. At screening and every 4 cycles, IWG response was evaluated. NGS evaluation of somatic mutations and DNA methylation analysis were performed at the same time points. DNA methylation pattern of separated BM CD34 positive cells was determined by Oxford Nanopore. At day1 of every cycle the EQ-5D questionnaire for QoL was administered. Feasibility, safety, tolerability as well as efficacy of oral-AZA were evaluated by monitoring AEs and response/loss of response, time to treatment discontinuation, and PRO. Results. As per July 31 st 2023, 11 HR-MDS patients with a median follow up of 167 days (range 47-805) were enrolled in this study. Male/female ratio was 4.5/1 with a median age of 81 yrs (67-88). At diagnosis patients belonged to IPSS-R risk categories intermediate 1/11, high 8/11, very high 2/11; IPSS-M risk categories at start of oral AZA: 3/11 very high, 6/11 high and 2/11 very low. Median number of sc-AZA cycles was 9 (range 7-52), while for oral-AZA median number of cycles was 4 (range 1-10). Oral AZA dose of 300 mg/day was maintained for all patients. DNA methylation was determined with success at baseline and every 4 cycles for all treated patients, and methylation status analyzed. None of the patients had serious adverse events related to study drug. Myelosuppressive effects were transient and Grade1/2. Patients maintained CR (4/11), PR (6/11) and SD with HI (1/11) achieved with sc-AZA, until progression. Therapy was interrupted for progression in 4 patients who evolved to AML after a median of 9 cycles of treatment with oral-AZA. Early discontinuation was experienced in 2/11 patients: in one case following a GI event grade 3 and patient decision to avoid de-escalation of the dose for subsequent cycles, in the second case because of patient reduced compliance. Both patients re-switched from oral to sc-AZA treatment and are still in response (PR). PRO analyses indicated that oral-AZA therapy improved most quality-of-life domains compared to sc-AZA. Treatment is ongoing for 4/11 patients in CR (3/4) and PR (1/4). Responses were observed across all IPSS-M risk categories. Conclusions Treatment of HR-MDS elderly patients with oral-AZAis feasible and effective. We observed duration of hematological response with a length consistent with what shown in this patient subgroup, and even after a very prolonged treatment with sc-AZA. Oral AZA was generally well tolerated and AEs did not differ from those observed for sc-AZA.

Azacitidine Combination with Lenalidomide in Treating Higher-Risk Myelodysplastic Syndromes: A Single-Center, Phase 2 Trial

Background: Azacitidine, which works through the proteosomic destruction of DNA methyltransferase and resultant chromatin decondensation, is used primarily in patients with higher-risk myelodysplastic syndromes (MDS). Lenalidomide has been approved by the US Food and Drug Administration for the treatment of MDS patients with del(5q) cytogenetic abnormality. It has also shown activity in patients with higher-risk MDS and acute myeloid leukemia. In this trial, we assessed the efficacy and safety of combining azacytidine and lenalidomide in higher-risk MDS. Methods: This is a single-center, phase 2 trial. Aza (75mg/m 2/d on days 1-7 of a 28-day cycle) was administered in combination with lenalidomide (10 mg/day on days 1 to 21 every 28 days) for patients. The primary endpoint was the overall response rate (ORR). Secondary endpoints were overall survival (OS), progression-free survival (PFS), and adverse events (AEs). An MDS targeted-exome-seq panel including 37 driver genes was used for screening. Results: Between Oct 2020 to Apr 2023, a total of 41 MDS patients were enrolled. 32 patients were evaluable for efficacy. 23 (71.875%) responded to therapy: 7 achieved a complete response (CR) (21.875%), 12 a marrow CR (mCR) (37.5%), and 4 a hematologic improvement (HI) (12.5%), of whom 10 of the mCR patients also had a HI. The median follow-up was 5.6 months (1 to 27.4), the median overall survival (OS) was not reached, and the median progression-free survival was 12.2 months. The time to reach CR was 2 months (range, 1 to 4.5), and the median CR duration was 8+ months (range, 5 to 27.4) ( Table 1). 27 patients had at least one mutation, the most common being TET2 (n = 12), ASXL1 (n = 12), TP53 (n = 7), SRSF2 (n = 6), and RUNX1 (n = 6) ( Fig.1A). Compared with patients without mutations, CR/mCR rate was significantly higher for those with mutations in TP53 (100% v 48%; P =0 .025) ( Fig. 1B), ORR were numerically higher for those with TP53 (100% v 64%; P = 0.149) and TET2 (85% v 63%; P = 0.422) ( Fig. 1C). We also observed a reduction of VAF in TP53 and TET2 mutation after the combination treatment ( Fig. 1D &amp; 1E). Common grade 3/4 nonhematologic adverse events included thrombocytopenia (18.75%), infection (12.5%), and febrile neutropenia (9.4%). Conclusion This trial demonstrated that the combination of azacytidine with a lenalidomide regimen is an effective therapy for higher-risk MDS patients, with high efficacy and well-tolerance. Patients with TP53 mutation appear more likely to achieve a CR/mCR.