Risk Myelodysplastic Syndromes Research Articles

Patterns of lower risk myelodysplastic syndrome progression: factors predicting progression to high-risk myelodysplastic syndrome and acute myeloid leukemia.

The patterns of low risk myelodysplastic syndrome (MDS) progression, and the clinical and molecular features of those patterns are not well described. We divided our low risk (LR) MDS patients (n=1914) into 4 cohorts: 1) Patients who remained LR-MDS (LR-LR; n=1300; 68%), 2) Patients who progressed from LR to HR MDS (LR-HR) without AML transformation (n=317; 16.5%), 3) Patients who progressed from LR to HR MDS and then AML (LR-HR-AML; n=124; 6.5%), 4) Patients who progressed from LR MDS to AML directly (LR-AML; n=173; 9%). Risk factors for progression included male gender, low absolute neutrophil count (ANC), low platelet count, high bone marrow (BM) blasts, ferritin >1000 mcg/L, albumin.

Effects of Black Raspberry Supplementation on Methylation Pathways in Vav-creAsxl1fl/flTet2fl/fl Double Knockout Mice with Early-stage Myelodysplastic Syndrome.

Myelodysplastic syndromes (MDS) are a subset of myeloid malignancies defined by clonality of immature hematopoietic stem cells that leads to faulty blood cell development. These syndromes can lead to an increased risk of infection and may transform into acute myeloid leukemia, making it critical to determine effective treatments for the condition. While hypomethylating agents such as azacitidine and decitabine, as well as stem cell transplants, have been delineated as favored treatments for MDS, not all patients are physiologically receptive to these treatments. However, black raspberries (BRBs) have been shown to exert hypomethylating effects in various malignancies, with minimal adverse effects and thus a broader range of potential candidacies. This study aimed to investigate the potential of BRBs to exert such effects on MDS using Addition of Sex Combs Like/Tet Methylcytosine Dioxygenase 2 (Asxl1/Tet2) double knockout mice (Vav-cre Asxl1fl/fl Tet2fl/fl), which typically manifest symptoms around 25 weeks of age, mirroring genetic mutations found in humans with MDS. Following a 12-week dietary supplementation of Vav-cre Asxl1fl/fl Tet2fl/fl mice with 5% BRBs, we observed both hyper- and hypomethylation at multiple transcription start sites and intragenic locations linked to critical pathways, including hematopoiesis. This methylation profile may have implications for delaying the onset of MDS, prompting a need for in-depth investigation. Our results emphasize the importance of exploring whether an extended BRB intervention can effectively alter MDS risk and elucidate the relationship between BRB-induced methylation changes, thus further unlocking the potential benefits of BRBs for MDS patients.

The Effect of Oral Iron Chelator Deferiprone on Iron Overload and Oxidative Stress in Patients with Myelodysplastic Syndromes: A Study by the Israeli MDS Working Group

<b><i>Background:</i></b> Most patients with lower risk myelodysplastic neoplasms or syndromes (MDSs) become RBC transfusion-dependent, resulting in iron overload, which is associated with an increased oxidative stress state. Iron-chelation therapy is applied to attenuate the toxic effects of this state. Deferiprone (DFP) is an oral iron chelator, which is not commonly used in this patient population, due to safety concerns, mainly agranulocytosis. The purpose of this study was to assess the effect of DFP, on oxidative stress parameters in iron-overloaded RBC transfusion-dependent patients with lower risk MDSs. <b><i>Methods:</i></b> Adult lower risk MDS patients with a cumulative transfusion burden of >20 red blood cell units and evidence of iron overload (serum ferritin >1,000 ng/mL) were included in this study. DFP was administered (100 mg/kg/day) for 4 months. Blood samples for oxidative stress parameters and iron overload parameters were done at baseline and monthly: reactive oxygen species (ROS), phosphatidylserine, reduced glutathione, membrane lipid peroxidation, serum ferritin, and cellular labile iron pool. The primary efficacy variable was ROS. Tolerability and side effects were recorded as well. A paired <i>t</i> test was applied for statistical analyses. <b><i>Results:</i></b> Eighteen patients were treated with DFP. ROS significantly decreased in all cell lineages: median decrease of 58.6% in RBC, 33.3% in PMN, and 39.8% in platelets (<i>p</i> < 0.01 for all). Other oxidative stress markers improved: phosphatidylserine decreased by 57.95%, lipid peroxidase decreased by 141.3%, and reduced gluthathione increased by 72.8% (<i>p</i> < 0.01 for all). The iron-overload marker and cellular labile iron pool decreased by 35% in RBCs, 44.3% in PMN, and 46.3% in platelets (<i>p</i> < 0.01 for all). No significant changes were observed in SF levels. There were no events of agranulocytosis. All AEs were grades 1–2. <b><i>Conclusions:</i></b> Herein, we showed preliminary evidence that DFP decreases iron-induced oxidative stress in MDS patients with a good tolerability profile (albeit a short follow-up period). No cases of severe neutropenia or agranulocytosis were reported. The future challenge is to prove that reduction in iron toxicity will eventually be translated into a clinically meaningful improvement.

Risk of Myelodysplastic Syndromes (MDS) in Adolescents and Young Adults with Cancers Treated with Chemotherapy with or without Radiotherapy

Introduction The risk of MDS among adolescents and young adults (AYA) with cancer treated with chemotherapy with or without radiotherapy in the US is not well understood. Method We interrogated NCI's Surveillance, Epidemiology and End Result (SEER)-17 registries to identify patients (pts) between the ages of 15-39 years (AYA) diagnosed with MDS at least one year after diagnosis of a primary unrelated cancer treated with chemotherapy and or radiotherapy over a twenty-year period (January 2000 to December 2020). All cancers, including MDS, were identified using ICD-O-3/WHO-2008 histology codes. We excluded all leukemia and MDS entities from index cancer sites. The risk of MDS was estimated by standardized incidence ratio (SIR), defined as the ratio of observed MDS cases in the AYA pts treated for first cancers to the expected number of MDS cases in the general US population during this period. A referent rate file for MDS incidence in age, gender, race and calendar-year matched US population available in SEER*Stat software (version 8.4.0) was used for SIR calculation. We calculated exact, 2-sided Poisson-based 95% confidence intervals (CIs) about the SIRs. We stratified the risk using 5- calendar year periods, and latency after index cancer diagnosis. SIR and time to MDS development was calculated for six most common index cancers using R(v4.2.2)-software. Result Of a total of 168,078 AYA pts eligible for analysis, with 1,290,803-person years at risk during 2000 to 2020, 66 pts developed MDS during this period. The median age at diagnosis of index cancer and MDS were 34 years (yrs) (interquartile range (IQR), 27-37 yrs) and 38 yrs (IQR, 32-44 yrs), respectively. There were 680% more cases of MDS in the AYA cohort compared to that expected in the matched general US population [SIR (95% CI): 7.80 (6.03-9.92), p<0.05)]. A higher SIR was observed for males (12.19) compared to females (5.82) and among all race/ethnicity, highest among black males [(SIR (95%CI): 18.99 (6.17-44.32), p<0.05]. We analyzed SIR for top-six index cancer sites that contributed to most MDS cases. Lymphomas [Non-Hodgkin (NHL) and Hodgkin (HL)] and breast accounted for 54.5% of all MDS cases. SIR for MDS in pts with NHL was 22.07 (95% CI: 12.61-35.84), in HL pts was 10.75 (95% CI: 4.64-21.18), and in breast cancer pts was 2.79 (95% CI:2.22-7.51). Even though the absolute number of cases was low, pts with brain, as well as bone and joint cancers had highest SIRs for MDS. When stratified by 5-calendar year periods, the SIR of MDS was elevated compared to general population through all periods and was highest during 2000-2005 (27.44; 95% CI: 11.03-56.53), and declined for the subsequent time periods. When analyzed by latency period, the SIR for MDS was highest at 1-3 years after index cancer diagnosis (21.46: 95% CI 13.45-32.50) and then showed a steady decline with increasing latency over a period of 15-20 years but never reached the rates observed in general population (Figure 1). Among the six most common index sites, pts with bone and joint cancer had earliest time to occurrence of MDS, whereas the longest latency to developing MDS was observed in pts with testicular cancer (Figure 2). Conclusion AYA cancer cohort treated with chemotherapy or radiotherapy have nearly 8-fold higher risk of future development of MDS compared to the same age matched general US population. This risk is highest during the initial 1-3 years of diagnosis of index cancer, declines over time, but never reaches the rates in the general population. These findings warrant further investigation to understand the biology behind this observation and have potential treatment and surveillance implications.

Methylation Biology of a Blood-Based MDS Risk Stratification Test

Background: Myelodysplastic syndromes (MDS) are a heterogeneous group of myeloid malignancies associated with a myriad of deleterious outcomes and a 5-year relative survival of 37%. MDS risk stratification is key for optimal treatment decisions. We previously demonstrated that methylation-based markers may help stratify MDS risk and achieved comparable performance relative to IPSS-R (the Revised International Prognostic Scoring System) by assessing the risk prediction ability of a classifier trained with features from either Bone Marrow (BM) whole-genome bisulfite sequencing (WGBS) or serum targeted methylation (TM) sequencing. Here, we elucidate the biological underpinnings of the methylation-based classifier and explore the survival stratification performance of our previously reported classifier. Methods: Utilizing datasets from BM WGBS and matched Serum TM sequencing of 127 patients with MDS (N=104) and secondary AML (N=23), we delineated the features used by the classifier by identifying differentially methylated regions (DMRs) that distinguished patients with overall survival of >3 years from those with <3 years. Our approach also included a functional enrichment and driver gene analysis associated with these DMRs, as well as cluster analysis across patients. We performed further evaluations of the survival outcomes of our BM WGBS and matched Serum TM prognostic classifier using concordance indices and log-rank tests. Results: Our analysis revealed 7,742 DMRs in BM WGBS and 14,093 DMRs in the Serum TM that significantly separated the long and short-term survival groups. Unsupervised hierarchical clustering of differential methylation patterns in both BM WGBS and Serum TM highlighted three distinctive subgroups of samples: short-term survivors, long-term survivors, and a group with intermediate survival outcomes. Notably, the short-term survivor group exhibited extensive hypermethylation across a majority of DMRs, which were linked to key biological pathways including calcium signaling, cAMP, MAPK, Rap1, and PI3K-Akt. Enrichment analysis of the BM WGBS DMRs between individuals with <3 and >3 years of survival underscored the differential hypermethylation of promoters, CpG islands, and CpG shores in association with worse survival outcomes. Our analysis of BM WGBS DMR driver genes via Hypergeometric Optimization of Motif EnRichment (HOMER) revealed potential contributors to differential survival outcomes, including known genes associated with MDS/AML, such as EWS/FLI-1, ERG, Pu.1, and RUNX1. Both pathway and driver gene analysis recapitulated previously known drivers of MDS to AML progression. The methylation classifier achieved comparable risk stratification performance for both BM WGBS comparing with IPSS-R (C-index: 0.69 [95% CI: 0.61-0.77] for methylation vs 0.71 [95% CI: 0.64-0.77] for IPSS-R) and Serum TM (C-index: 0.68 [95% CI: 0.60-0.75] for methylation vs. 0.70 [95% CI: 0.63-0.78] for IPSS-R). At a specificity threshold of 0.8, both BM WGBS and Serum TM prognostic classifiers were able to stratify between predicted short and predicted long survivors (BM WGBS HR: 2.83, p<0.0001; Serum TM HR: 3.01, p=0.0008). Conclusions: Our findings generated biological insights into the methylation-based risk stratification of MDS, shedding light on the specific genomic features and biological pathways that underlie these methylation patterns. We also demonstrated that methylation-based MDS risk stratification performs comparably with IPSS-R. These insights not only expand our understanding of the complexity of MDS, but also reinforce the potential of methylation-based sequencing as a viable, possibly less-invasive, alternative for MDS risk stratification compared to traditional IPSS-R methods.

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<0.01, and 2.1% vs 1.5% Hispanic, p<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<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.

Mutational Profile and Dynamics of PPM1D-Mutant Clones in the Spectrum of Myeloid Disorders

Introduction Mutations in PPM1D a regulator of DNA damage response, are enriched in patients with clonal hematopoiesis (CH) exposed to cytotoxic treatment or with therapy-related myeloid neoplasm. However, their role in leukemic transformation is unclear. Here, we describe a large cohort of patients with PPM1D mutations from CH to acute myeloid leukemia (AML) to understand the molecular landscape of mutant PPM1D related disease and the longitudinal dynamics of CH under treatment. Methods We included, in a non-sequential cohort, 96 PPM1D mutated patients treated at Gustave Roussy with CH, clonal cytopenia of unknown significance (CCUS), myelodysplastic syndrome (MDS), myeloproliferative neoplasm (MPN) or AML. A 77 gene panel NGS analysis was performed. An additional 16 PPM1D mutated AML patients from ALFA trials (1200, 0701,0702) were included. 10 patients with ovarian cancer from this cohort had sequential blood samples (OvBIOMark trial) available prior to hematologic evaluation, from the diagnosis or first relapse of their cancer through the course of therapy. Those samples were analyzed with a UMI based 18 gene panel (HaloplexHS, Agilent). Overall survival (OS) analyses were performed with the Kaplan-Meier method from the time of diagnosis until death from any cause. Results Among the 112 patients with PPM1D mutations, 23 (21%) had CH, 36 (32%) CCUS, 19 (17%) MDS, 25 (22%) AML (including 4 relapses), and 9 (8%) MPN. Median age was 65 [range, 21-88] years with 67% of females. Only 18% of the patients had no previous cancer history. Most frequent primary cancers were gynecological cancer (27%), lymphoid malignancies (22%), and breast cancer (17%). Median time between primary cancer diagnosis and hematologic assessment was 5.3 [range, 1.2-8.5] years. Eighty six percent of patients had one PPM1D mutation, 9% had 2, and 5% had 3 or more (restricted to CH and CCUS). Median variant allele frequency (VAF) was 3% [0.2-38], 3% [1-31], 2.4% [1-41], 23% [1-50], and 4% [1-42] in CH, CCUS, MDS, AML and MPN, respectively. Among CH/CCUS patients, PPM1D was the sole detected somatic mutation in 39% (23/59), compared to 9% (5/53) in MDS/AML/MPN patients (odds ratio=6, p=0.0004); 3/5 of the latter had complex karyotype. The most frequently co-mutated genes were DNMT3A (29%) and TP53 (25%), uniformly across all conditions ( Fig 1A). MDS-related gene mutations, RUNX1 (7%), ASXL1 (4%), SF3B1 (4%), SRSF2 (4%), U2AF1 (4%), were specific to AML/MDS/MPN. Among 28 patients with both PPM1D and TP53 mutations, PPM1D mutations were dominant or co-dominant in 64% (18/28), and secondary in 36% (10/28). IPSS-M risk of evaluable MDS was high/very high in 54% (7/13) of patients. ELN 2022 classification of AML was adverse in 68% (17/25) of patients. AML treatment options included best supportive care for 8% of patients (2), 5-Azacytidine for 32% (8), intensive chemotherapy for 60% (15). With a median follow up of 2.4 years, the median OS was 4.6 (CI95%; 4.1-NA), 1.31 (CI95%; 0.53-NA), 1.27 (0.43-NA), 0.66 (CI95%; 0.42-1.26) and 20.4 (CI95%; 20.4-NA) years for CH, CCUS, MDS, AML and MPN, respectively. TP53 mutation status did not stratify OS. Four ovarian cancer patients with CH/CCUS transformed to MDS/AML with a median of 5.3 [1-12] years. At transformation, 3/4 had a stable PPM1D mutation, 1/4 an increase in PPM1D VAF (2 to 28%), and 3/4 had TP53 mutations before and at transformation. We analyzed 67 timepoints from 10 ovarian cancer patients during therapy (median 7 per patient). 10/10 received alkylating agents and 5/10 PARPi. The median number of mutations per patient was 4 and 6 at baseline and last follow-up, respectively. PPM1D-mutated clone size increased from 0.4% [0.1-3] at baseline to 7% [2-30] at last follow-up. Beyond clonal expansion, PPM1D VAF dynamics showed non-linear changes related to alkylating agents exposure: 2/10 patients had a continuous expansion, 2/10 had expansion then contraction (GR-1/3, Fig 1B), and 6/10 had expansion then stabilization (GR-2, Fig 1B). Conclusion We described a large cohort of PPM1D mutated patients from CH to AML. Their prognosis was poor independently of TP53 mutation at AML/MDS stage. PPM1D mutations were frequently part of the dominant clone. To confirm the clonal architecture, single cell sequencing analysis in 8 AML/MDS patients are ongoing. Trajectory of PPM1D mutations in ovarian cancer patients revealed a non-linear alkylating agent dependency which warrants further investigation.

Results of a Phase II Study of Cladribine, Low Dose Cytarabine and Venetoclax, Alternating with Azacitidine and Venetoclax in Patients with Higher Risk Chronic Myelomonocytic Leukemia or Myelodysplastic Syndromes

INTRODUCTION: Clinical responses to hypomethylating agents (HMAs) in patients (pts) with higher-risk myelodysplastic syndromes (HR-MDS) and myeloproliferative chronic myelomonocytic leukemia (CMML) remain short-lived, with high risk of transformation to acute myeloid leukemia (AML). Prior data suggests use of the purine analogue cladribine can induce monocyte apoptosis and is active in AML, particularly in combination with low dose cytarabine (LDAC) and venetoclax. We aimed to evaluate the safety and activity of cladribine, LDAC and venetoclax in HR-MDS and CMML. METHODS: We designed a phase II basket clinical trial of cladribine combined with LDAC and venetoclax alternating with azacitidine and venetoclax for pts with HR-MDS or CMML. Pts were divided into 4 cohorts: cohort A: MDS with int-1 to high risk by IPSS and >5% blasts with prior HMA-failure (HMA-F); cohort B: CMML-1/CMML-2 with prior HMA-F; cohort C: previously untreated MDS with Int-2 or High risk by IPSS and >10% bone marrow (BM) blasts; cohort D: previously untreated CMML-2 or CMML-1 with at least one high-risk feature (extramedullary disease, splenomegaly of >5cm below costal margin, platelets <100x10 9/L, Hgb level <10g/dL, WBC >13x10 9/L, clonal cytogenetic abnormality [other than monosomy Y]). HMA-F was defined as no response after 6 cycles of therapy with HMA or relapse/progression after any number of cycles. Induction consisted of cladribine 5mg/m 2 daily IV on days 1-3, cytarabine 20mg s.c bid days 1-5 and venetoclax 400mg daily days 1-5. Re-induction was allowed in pts not achieving response after induction. Consolidations consisted of azacitidine 75mg/m 2 daily days 1-7 with venetoclax 400mg daily days 1-7 alternating with cladribine 5mg/m 2 days 1-3, cytarabine 20mg s.c bid days 1-5 and venetoclax 400mg days 1-5 every two 28-day cycles. The primary end point was to evaluate safety, efficacy, and tolerability of the combination. Responses were evaluated following 2006 IWG criteria. The Kaplan-Meir product-limit method was used to estimate median survival. RESULTS: Between October 2022 and June 2023, 20 pts have been treated: 10, 5, 3 and 2 in cohorts A, B, C and D, respectively. Thirteen pts had MDS, and 7 had CMML. Median age was 74 years (range 52-83). Among MDS pts, 8 (62%) had int-2 and 5 (38%) had high risk by IPSS. By the Molecular IPSS, 10 (79%) had very high, 1 (8%) had high, 1 (8%) had moderate high and 1 (8%) had low risk. Among CMML pts, 4 (57%) had high, 2 (29%) had intermediate-2 and 1 (14%) had intermediate-1 risk by the CPSS Molecular score. Among HMA-F cohorts, median number of prior therapies was 1 (range 1-4), median cycles of prior HMA was 6 (range 2-63) and 4 (27%) pts had failure to prior venetoclax therapy. Most common adverse events (AEs) were hypoalbuminemia (40%), nausea (40%), sinus bradycardia (40%), alanine aminotransferase increase (35%), constipation (35%), lower extremity edema (35%), fatigue (35%) and hypocalcemia (35%) Most common grade 3-4 AEs were leukopenia (20%) and febrile neutropenia (15%). The 4-week and 8-week cumulative incidences of mortality were 0%. Median number of cycles was 2 (range 1-6). Median cycles to best response was 1 (range 1-3). Among HMA naïve pts (cohorts C and D), the ORR was 80% (n=4): CR in 2 (40%), mCR in 2 (40%). Based on 2023 IWG response criteria, responses in cohort C (n=3) included: CR in 2 (67%) and CR bilineage (CRbi) in 1 (33%). Based on 2015 IWG MDS/MPN criteria, responses in cohort D (n=2) included optimal marrow response and clinical benefit in 1 (50%) and 1 (50%) pts, respectively. Among HMA-F pts (cohorts A and B) the ORR was 20%: 1 CR (10%) and 1 (10%) mCR with HI. Median follow up is 5.3 months (95% CI 2.4-81). Median EFS is 2.1 months in cohorts A and B and not reached in C and D (Fig 1A). Median OS has not been reached for all cohorts (Fig 1B). At the time of data cut-off, all pts in cohorts C and D discontinued study to proceed with hematopoietic stem-cell transplantation (HSCT). Among cohorts A and B, 2 pts (13%) discontinued study to proceed with HSCT, 5 (33%) due to transformation to AML, 2 (13%) due to no response, 2 (13%) due to physician choice, 1 (7%) due to patient choice and 2 (13%) pts remain on study. CONCLUSIONS: Preliminary data suggests the use of cladribine, LDAC and venetoclax can be safely administered in pts with very high risk MDS and CMML with early promising results in pts with de novo disease.

Phase 1/2 Multicenter, Open-Label Study of CTX-712 in Patients with Relapsed/Refractory Acute Myeloid Leukemia and Higher Risk Myelodysplastic Syndromes

Background and Significance Dysregulation of alternative splicing, caused by abnormal expression or mutation of splicing factors, has been identified as an important contributor to the genesis and progression of cancer, and suggested as a novel target for anticancer treatment. CDC2-like kinases (CLK) represent a family of dual-specificity tyrosine and serine-threonine kinases that are involved in the regulation of splicing by phosphorylation of serine/arginine-rich splicing factors (SRSFs) which play a central role in exon recognition. CTX-712 is an orally available, potent, selective, and a first-in-class pan-CLK inhibitor (CLK 1-4), that inhibits phosphorylation of SRSFs resulting in significant antitumor activity in vitro and multiple xenograft models in vivo. CTX-712 formulated in capsules is currently being evaluated in an ongoing first-in-man study in Japan, evaluating tolerability and early efficacy in patients with solid tumors or hematologic malignancies (JapicCTI-184188). Preliminary data from the Japanese study were presented during ASCO 2022 and ASH 2022, and showed an acceptable safety profile (doses up to 175 mg (MTD 140 mg) twice a week in 28-day cycles, observed DLTs included dehydration, decreased platelets, hypokalemia, and pneumonia) with early signs of clinical antitumor activity (2 partial responses / 26 treated solid tumor patients, 5 complete remissions and complete remission with incomplete hematologic recovery/ 8 treated patients with AML or MDS), warranting further clinical investigations.. (J Clin Oncol (2022) 40(16_suppl):3080. Blood (2022) 140(Supplement 1):6211-2.). This abstract details a second study with CTX-712 that has just been initiated. Study Design and Methods A new film-coated tablet formulation will be evaluated in this phase 1/2 multicenter, open-label study of CTX-712 in patients with (mutated or wild type spliceosomes genes) relapsed/refractory AML, higher risk MDS (IPSS-R intermediate, high, or very high), or high marrow blast (≥5 %) MDS/MPN (including CMML). The phase 1 part of the study will be conducted at 4 US sites, and all sites are currently open for enrolment. The study allows patients with performance status 0, 1, or 2, adequate organ function, and up to four prior lines of therapy. Due to potential risk of interactions (in vitro studies suggest CYP3A4 as main metabolic pathway for CTX-712), concomitant use of strong CYP3A4 inhibitors is prohibited. Use of azole antifungals that are not strong CYP3A4 inhibitors (e.g., isavuconazole) is permitted. The phase 1 part of the study consists of dose-escalation (sequential standard 3 + 3 design), where cohorts of 3 (or 6) patients will receive ascending doses of CTX-712 once weekly in a 28-day cycle with continuous monitoring of emerging clinical PK, PD, safety, and efficacy data, to determine the recommended phase 2 dose (RP2D) based on the suggestion by the Safety Review Committee (SRC). The protocol defines five different dose levels (20-140 mg, once weekly) but also authorizes the SRC to suggest up to two interim dose levels or alternate schedules (e.g., dosing two times a week) if supported by emerging data. The suggested RP2D will be used in a confirmatory phase 1 expansion cohort where an additional 10 patients (total n = 16; 8 patients with AML and 8 patients with MDS) will be treated to gain further confidence in the selected dose level. The phase 2 part of the study will commence after the RP2D has been identified and confirmed and aims at evaluating therapeutic activity in R/R AML (Cohort 2a) or R/R HR-MDS (Cohort 2b), in addition to confirmation of the safety profile. Clinical trial registry number: NCT05732103

Single-Cell Multiomics Analysis Reveals Potential Drivers of Response to the Anti-TIM3 Inhibitor Sabatolimab Combined with Azacitidine in MDS and CMML

Background The median survival for patients with newly diagnosed (ND) higher risk myelodysplastic syndrome (MDS) and chronic myelomonocytic leukemia (CMML) remains poor. The potential curability of MDS and CMML with allogeneic hematopoietic stem cell transplantation supports the concept of anti-tumor immunity and has led to interest in evaluating immune-based therapeutic approaches in myeloid neoplasms. The immune checkpoint molecule TIM-3 (encoded by the gene HAVCR2) is a target of interest in myeloid neoplasms given its expression on leukemic stem cells as well as several subsets of immune cells including T cells, monocytes, dendritic cells and NK cells. Sabatolimab (MBG453) is an investigational IgG4 anti-TIM-3 antibody currently under evaluation for myeloid neoplasms. In this exploratory study, we sought to characterize the effects of sabatolimab combined with the hypomethylating agent (HMA), azacitidine, on the immune landscape using single cell sequencing of samples from subjects with MDS and CMML treated with the combination from a previously reported phase 1b study (NCT03066648; Brunner et al 2022). Methods Following IRB approval, single-cell RNA sequencing (scRNA-seq) and associated proteomic cellular indexing of transcriptomes and epitopes sequencing (CITE-seq) was performed on both blood (BLD) and bone-marrow (BM) derived samples from subjects with: 1) MDS (n=3) or CMML (n=2) treated with HMA therapy alone as part of standard care; 2) ND MDS (n=5) or CMML (n=3) treated with azacitidine combined with sabatolimab; and 3) relapsed/refractory MDS (n=3) treated with sabatolimab alone. Paired BLD and BM samples as well as samples from serial treatment time points were selected whenever feasible (Fig 1). A total of 206,183 cells from BM and 172,421 cells from BLD post-quality control filtering were analyzed. Further, scRNAseq data from normal BLD(200,000 cells) and BM(240,650 cells) generated as part of the human cell atlas (https://data.humancellatlas.org/explore/projects/cc95ff89-2e68-4a08-a234-480eca21ce79) were integrated with this dataset to assist with immune cell subset characterization, enable downstream comparisons to healthy hematopoietic cells, and to help define cell subsets associated with disease states. Results In baseline samples from subjects with MDS treated with azacitidine-sabatolimab, we found that an increased baseline abundance of interferon-responsive CD8 T cells in both the BM and BLD (FDR<0.1) was associated with response to therapy. An increased baseline abundance of plasmacytoid dendritic cells and a granulocyte population also suggested an association with response to therapy. Differential gene expression analysis of baseline samples from responding versus non-responding subjects with MDS treated with azacitidine-sabatolimab showed a higher baseline expression of TNF and IFNG in BM CD8 T cells and up-regulated expression of MHC-II machinery ( HLA-DRB1, HLA-DPA1, CD74) in myeloid cell subsets in responding subjects (FDR <0.1), suggesting that pre-treatment ability of these cells to be involved in antigen-presentation may play a role in response. In subjects with CMML treated with azacitidine-sabatolimab, we observed dynamic changes in cellular abundances and gene expression when comparing baseline to post-therapy timepoints. Specifically, BM CD8 T cell subsets showed an up-regulation of cytotoxicity genes ( GZMA), interferon response genes ( IFIT2, IFITM1, IFITM2) and IL32 cytokine post-therapy (FDR <0.1). When evaluating myelomonocytic cell populations, we observed an increase in CD16 monocytes post-treatment. Additionally, dendritic cells and monocytes showed an up-regulation of interferon response genes ( IFIT1, OAS1, IFI27). Conversely, we observed a down-regulation of metallothionein genes ( MT1E, MT1G, MT2A) as well as a collection of transcription factors ( NR4A1, FOSL2, JUN, CEBPB, CEBPD), NF-κB inhibitors ( NFKBIZ, NFKBIA) and CXCL8 in the post-treatment samples (FDR <0.1). Conclusions Our study provides one of the most comprehensive evaluations of the cellular dynamics of anti-TIM3 immunotherapy in patients to date, allowing for the nomination of novel putative predictive biomarkers of response and identification of potential immunomodulatory mechanisms induced by the combination of sabatolimab with azacitidine in MDS and CMML for further future analysis.

Hematological Response to Frontline Treatment in Lower Risk Myelodysplastic Syndromes (LRMDS) Is Associated with Better Overall Survival

Background The majority of LRMDS patients (pts) (70%) do not progress but unfortunately succumb to complications related to cytopenia, namely anemia and red blood cell transfusion dependency (RBC-TD) or their interplay with co-morbidities. RBC-TD is associated with worse outcome reflecting bone marrow failure and long-term sequela of RBC-TD. There is growing evidence that response to treatment and RBC transfusion independence (TI) are associated with favorable outcome. In lieu of 2 recent randomized clinical trials demonstrating efficacy of luspatercept & imetelstat in LRMDS, we assessed the impact of response to sequential lines of treatment in LR-MDS on overall survival (OS) to guide our treatment choices and to determine whether erythroid stimulating agents (ESA) should still be our 1 st line of therapy. Methods We included LRMDS pts (IPSS-R very low & low) from Moffitt Database who received ESA as frontline therapy (FL) and assessed subsequently outcomes with second line (SL) therapy (SOC or clinical trial). We excluded MDS/MPN and del5q pts. We also excluded all pts who eventually progressed to either higher risk MDS or AML to better reflect the majority LRMDS in that disease state. We assessed details of FL and SL. Pts who received FL & SL were then divided into 4 groups based on response to FL and SL therapy: group 1 (no/no), group 2 (no/yes) with response only to SL, group 3 (yes/no) response to FL only, and group 4 (yes/yes) with response to both lines of therapy. Response was defined as hematological improvement (HI) with ≥1.5 g/dl Hgb increase in non-TD pts and RBC-TI in TD pts at baseline for at least for 8 weeks. We compared median OS (mOS) among those groups. Results There were 603 LRMDS pts who met eligibility criteria and received ESA as FL (Table-1); 43% were RBC-TD, mean serum EPO was 132 (n=211 pts), 69% received epoetin, 17% darbepoetin and 14% with G-CSF. HI was observed in 42% of pts with no difference among ring sideroblasts (RS) +/- (46% vs 40%, p =.12). Response was higher among non-RBC-TD (52% vs 31%, p< .001). The median time to start ESA was 1.2 mo (0-249). The median time on ESA therapy was 11 mo (.4-213). 331 pts (55%) received SL which included HMA 43% (n= 142), lenalidomide 39% (n=130), luspatercept 7% (n=24), ATG 2% (n=8), investigational agent 4% (n=14), and other 4% (n=13) . The HI rate was 27% (91/331). No difference in HI based on RS nor RBC-TD was observed. The median duration on SL treatment was 6 mo (.1-93). 170 pts (28%) received 3 rd line of therapy with 7% HI, 88 pts (15%) received 4 th line of therapy with 3% HI and 39 pts (7%) had 5 th line of therapy with 2% HI. Among the 331 pts who received at least FL and SL, pts were divided into 4 groups based on response to (methods, table-2), the mOS was 114 mo among Yes/Yes response group, 103 mo among yes/no group, 97 mo no/yes and 64 mo among no/no ( P=.007; Figure-1). Response to FL was significantly associated with better OS after adjusting for RS (HR .74 ,95% CI .55-.99, p=.043). Conclusions Only half of patients who receive ESA as FL therapy for LRMDS received any subsequent therapies. Response rates were highest with ESA as FL than any SL therapy. HI with FL and/or SL is associated with improved OS. Lack of response to first line of therapy is associated with worse OS. Responses beyond SL were rarely observed. Identifying and moving agents with high HI rate as FL therapy and or selecting option based on predictors of best chance of response to a specific treatment as FL may lead to better overall survival.

AK117 (anti-CD47 monoclonal antibody) in Combination with Azacitidine for Newly Diagnosed Higher Risk Myelodysplastic Syndrome (HR-MDS): AK117-103 Phase 1b Results

Background: CD47, an immune checkpoint overexpressed by tumor cells, plays a crucial role in evading the antitumor immune response. AK117, an IgG4 monoclonal antibody (mAb) targeting CD47, has emerged as a potential best-in-class therapy with high affinity binding to CD47 and without inducing hemagglutination effects. By blocking CD47, AK117 effectively triggers macrophage-mediated phagocytosis of hematological malignancy cells, and in combination with azacitidine (AZA), it synergistically enhances the activation of “eat me” signals. In this study, we present the Phase 1b data from the AK117-103 study conducted in patients with newly diagnosed higher risk myelodysplastic syndrome (HR-MDS). Methods: Eligible patients with newly diagnosed intermediate/high/very high-risk MDS, determined by the Revised International Prognostic Scoring System (IPSS-R) prognostic risk score >3, were enrolled to receive combination therapy with AK117 and AZA. AK117 was administered intravenously (IV) following various dosing regimens (20-30 mg/kg once weekly [QW], or 20-45 mg/kg every 2 weeks [Q2W], or 30 mg/kg every 4 weeks [Q4W]), whereas AZA was administered subcutaneously (SC) at the standard dosage (75 mg/m 2, Day 1-7, Q4W). The primary endpoints of this study were safety/tolerability and the complete remission (CR) rate based on the International Working Group (IWG) 2006 response criteria. Results: As of June 9, 2023, 72 patients were enrolled (median age: 66 years, 69.4% males). Most patients exhibited abnormal hematologic conditions at baseline, including decreased hemoglobin, neutrophil count, and platelet count. Specifically, 69.4% of patients had Grade ≥3 anemia, 61.1% had Grade ≥3 neutrophil count decrease, and 47.2% had Grade ≥3 platelet count decrease. For the recommended phase 2 dose (RP2D) group, treated with a combination of AK117 30 mg/kg Q2W and AZA, 30 patients were enrolled with a median age of 67 years, 80.0% of whom were males. According to IPSS-R risk assessment, 33.3%, 23.3%, and 43.3% of patients had intermediate, high, and very high risk, respectively. 30.0% of patients had poor-risk cytogenetics, with 23.0% of those being complex. After a median follow-up of 6.6 months (ranging from 0.4-17.2 months), anemia (a primary adverse event associated with CD47 blocking antibodies) occurred in 30.6% (22/72) of the patients, of which Grade ≥ 3 anemia accounted for 22.2% (16/72). Other commonly observed treatment-emergent adverse events (TEAEs) (≥30%) included decreased neutrophil count (77.8%), decreased white blood cell count (72.2%), decreased platelet count (69.4%), pyrexia (58.3%), decreased lymphocyte count (41.7%), constipation (41.7%), and vomiting (31.9%). Three patients (4.2%) discontinued treatment due to TEAEs. The efficacy of AK117 was compared at different dosages, and ultimately, 30mg/kg Q2W was chosen as the RP2D. As of June 21, 2023, among 27 evaluable patients, the CR rate was 48.1%. 8 patients achieved marrow CR (5 also with hematologic improvement [HI]), and 2 patients achieved HI alone. Among 24 evaluable patients with ≥ 3 months follow-up, the CR rate further escalated to 54.2%. Of 13 evaluable patients who initially required red blood cells (RBC) transfusions, 8(61.5%) became independent of RBC transfusion. Conclusions: AK117 in combination with AZA was well tolerated with low incidence of anemia and demonstrated promising efficacy in patients with newly diagnosed HR-MDS.

“Transplant Changes Your Life”: Communication Strategies of Transplant Hematologists in High Risk Decision Making Conversations

Introduction: Allogeneic hematopoietic cell transplantation (alloHCT) offers a chance of cure for many patients with blood cancers including higher risk myelodysplastic syndromes (MDS) but carries many risks. In this high risk, high reward situation, shared decision making is essential to empower patients to make goal-concordant decisions. We detail communication strategies hematologists use to discuss treatment options including alloHCT and to facilitate shared decision making with patients. Methods: Our research team recruited hematologists who routinely perform alloHCT in the United States through email. Participants conducted a video-recorded virtual encounter lasting up to one hour with an actor portraying a 67-year-old man with recently diagnosed high risk MDS referred for specialty hematology consultation to discuss treatment options including alloHCT. We transcribed and qualitatively analyzed hematologists' communication approaches. Results: Participants (n=37) from 25 institutions were a median age of 44 years (range 33-73 years) and mostly male (65%) and white (65%). More than half spent >50% of their clinical time in managing alloHCT patients. Hematologists followed a similar conversation structure, though varied in the amount of detail they provided within each of the main sections (Figure 1). Their conversation routinely included an assessment of the patient's perception of his condition, information about MDS, and discussion of treatment options including transplant and chemotherapy and less commonly supportive care or a clinical trial. Many repeatedly highlighted that transplant was the only option with the potential for cure. Their discussion about transplant frequently followed a chronological approach from pretransplant considerations including donor issues, formal fitness testing, and disease control; to the peri-transplant period and hospital experience; and through the posttransplant course including need for dedicated caregiver support. Hematologists discussed risks, complications, and major outcomes at varying lengths. Decision making talk occurred at different points in the visit though was often concentrated in the latter part of the conversation. Hematologists referred to several elements that formed the basis of treatment decision making (Figure 2). While hematologists indicated that multiple factors should inform the patient's and hematologist's decision making, many honed in on transplant's position as the only chance for long-term survival. Although most hematologists acknowledged on a general level the importance of patients' goals and preferences in decision making, they elicited and incorporated the individual patient's specific goals into the discussion to varying degrees. Instead, in several conversations, hematologists' assessment of the patient's fitness and candidacy for transplant was prominent in their discussion about whether the patient could and should consider pursuing the curative option. Hematologists frequently recommended that the patient take time to think and talk with his family about the treatment decision in the immediate future. The strength of their longer-term recommendations ranged from strong recommendations for transplant or chemotherapy to conditional recommendations for transplant or deferral pending further information. These recommendations reflected a range of decision-making strategies, from a physician-led approach to a primarily patient-guided effort. In the middle, some hematologists described a collaborative effort with the patient, in which the patient and hematologist would work together to reach a shared decision. Within a single encounter, many hematologists expressed various statements suggesting that their approach to decision making did not fit tightly within a single domain but rather fell along a continuum which evolved as the encounter proceeded. Conclusions: The transplant decision making discussion is complex. The ways in which hematologists frame information and engage patients affect how they make decisions together. Hematologists consistently discuss similar major content areas as they navigate from beginning to end; identification of these key components can be used as the basis for creation of a communication tool to help hematologists discuss alloHCT with patients.

A Phase II Study of Single Agent Aspacytarabine (BST-236) in Adults Unfit for Intensive Chemotherapy with Relapsed or Refractory Acute Myeloid Leukemia (R/R AML) or Higher Risk Myelodysplastic Syndromes (R/R HR MDS)

Background-Common treatment approaches for R/R AML and to some extent HR MDS involve intensive chemotherapy regimens, typically combining high dose cytarabine with other drug(s), but these intensive regimens may not be suitable for unfit or elderly patients. To address this issue, a cytarabine prodrug called BST-236 has been developed, which delivers high doses of cytarabine while reducing systemic toxicity, making it a potential option for intensive chemotherapy in older and frail patients. This Phase II study aimed to assess the efficacy and tolerability of BST-236 in unfit patients with R/R AML or HR MDS previously treated with a non-intensive regimen. Methods-This ongoing Phase 2 trial (NCT 04827719) enrolled HR MDS and AML patients (pts) aged ≥ 75 years or with comorbidities incompatible with intensive chemotherapy. MDS pts were refractory or had relapsed to azacytidine (AZA), and AML pts to AZA, low-dose cytarabine (LDAC) or AZA -venetoclax (VEN), given as a first line regimen. Each BST-236 induction and maintenance course consisted of 6 daily 1-hour intravenous infusions at a dose of 4.5 g/m 2/d (containing 3 g/m 2/d of cytarabine). After completing 1 induction cycle, patients with stable disease (SD) or partial response could undergo a second similar cycle, and patients who achieved complete remission (CR) could receive 2 to 4 maintenance cycles at the same schedule. Inclusion of 20 AML and 20 MDS pts was planned. Results-From August 2021 to May 2023, 16 MDS and 20 AML pts from 9 centers were enrolled, with a median follow up of 3 months. MDS: Median age was 74.8 years [IQR, 71.2-76.4] and ECOG was 0- 1 in all but 1 patient . All pts were previously treated with AZA and 4 (29%) had adverse R-IPSS karyotype. 14/16 were evaluable for response after 1 induction: 1 (7%) CR, 2 (14%) marrow CR, 7 (50%) SD. Hematological improvement was observed in 6 (43%) patients. Two serious treatment related adverse events (SAE) - febrile neutropenia and sepsis - occurred in 2 pts. Median duration of hospitalization for the induction cycle was 29.5 days [IQR 25.5-32.5] and 30-day mortality rate was 0%. AML: Median age was 77.6 years [IQR, 73.8-79.4] and all pts had ECOG 0-1. Two pts were previously treated with AZA, 1 with LDAC, 17 with AZA-VEN and 8 (50%) had adverse ELN score. 17/ 20 pts were evaluable for response after 1 induction cycle : 2 (12%) CR including 1 CR with negative MRD, 1 (6%) CRi, 10 (59%) SD. Three SAE- infections and hepatobiliary disorders- occurred in 2 pts. Median duration of hospitalization for the induction cycle was 26 days [IQR 23.2-30.8] and 30-day mortality rate was 10%. Four MDS pts still need to be enrolled, and follow up is ongoing. An update will be presented at the meeting. Conclusion- Response rates with BST-236, in this pretreated older frail R/R AML and MDS population, were modest. Toxicity, including myelosuppression, however appears lower than with conventional intensive chemotherapy, suggesting this treatment could be interesting earlier in the disease course.

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.

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 > 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.

Efficacy and Tolerability of Luspatercept in Patients with Lower Risk Myelodysplastic Syndrome and Anemia: A Systematic Review and Meta-Analysis of Phase III Randomized Controlled Trials

Introduction: Erythropoietin Stimulating Agents (ESAs) are the standard-of-care treatment for most patients with lower risk myelodysplastic syndrome (MDS) and anaemia. However, there has been unmet need for those who failed ESAs other than regular blood transfusion. Luspatercept is a recombinant fusion protein which binds TGF beta ligands resulting in reduction of erythroid maturation through reduction of SMAD2 and SMAD3 signaling. In recent years, studies have shown that luspatercept has significantly improved efficacy in patients with lower risk MDS who failed ESAs with some notable adverse events. The purpose of our meta-analysis is to determine efficacy by observing the rate of transfusion independence for 12 weeks or longer and haematological improvement in erythroid (HIE), and tolerability by rate of treatment emergent serious adverse events (SAE), treatment discontinuation (TD) and treatment interruption (TI) or dose reduction and treatment related mortality in patients with lower risk MDS treated with luspatercept. Methods: We systematically conducted a comprehensive literature search using MEDLINE, EMBASE databases and meeting abstracts from inception through June 30 th, 2023. Phase III RCTs utilizing luspatercept in patients with lower risk MDS that mention efficacy i.e. transfusion independence 12 weeks or longer and HIE and tolerability i.e. rate of treatment discontinuation and interruption, dose reduction, treatment emergent serious adverse events, treatment related mortality were incorporated in the analysis. Mantel-Haenszel (MH) method was used to calculate the estimated pooled risk ratio (RR) with 95% confidence interval (CI). Heterogeneity was assessed with Cochran's Q- statistic. Fixed effects model was applied. Results: 2 phase III RCTs (MEDALIST and COMMANDS) including total 583 patients were eligible in our meta-analysis. MEDALIST trial compared luspatercept vs placebo and COMMANDS trial compared luspatercept vs erythropoietin stimulating agent. The randomization ratios were 2:1 in MEDALIST and 1:1 in COMMANDS trials. Transfusion independence for 12 weeks or longer was noted in 141 (47%) in study arm vs 77 (33.5%) in control arm at RR of 1.67 (95% CI: 1.35 -2.06; P <0.00001). 190 (63.3%) patients in study arm achieved HIE response compared to 88 (38.3%) in control arm at RR of 1.85 (95% CI: 1.53 -2.24; P<0.00001). TD due to TEAE was reported in 21 (6.3%) of luspatercept group vs 10 (4%) in control group with RR of 1.38 (95% CI: 0.67 -2.84; P = 0.39). The incidence for TI or dose reduction due to TEAE was similar between the two groups at 18% with RR of 1.23 (95% CI: 0.88 -1.72; P = 0.22). Treatment emergent SAEs were observed in 116 (35%) in the luspatercept group vs 83 (32.9%) in control group (RR, 1.09; 95% CI: 0.87-1.38; P=0.45). Treatment related mortality was noted in 13 (3.9%) of patients in the study group compared to 16 (6.3%) in the control group with RR of 0.65 (95% CI: 0.31 -1.33; P = 0.24). Conclusions: According to our meta-analysis, luspatercept significantly improved transfusion independent rate and HIE response in patients with lower risk MDS and anaemia compared to control arm. Furthermore, there was no statistically significant difference in the treatment emergent SAEs, treatment discontinuation, treatment interruption or dose reduction and treatment related mortality between the two groups.

Clonal Hematopoiesis in Patients with Immune Thrombocytopenia: Preliminary Results of a Cross-Sectional Study

Immune thrombocytopenia (ITP) is an acquired disorder marked by immune-mediated attack to platelets. However, the borders between ITP and clonal cytopenias, such as low risk myelodysplastic syndromes, may be difficult to establish. Detection of somatic mutations on peripheral blood leukocytes (PBL) through next generation sequencing (NGS) is gaining diagnostic and prognostic power in myeloid disorders and may be found also in individuals without blood malignancies, namely clonal hematopoiesis with indeterminate potential (CHIP). The prevalence and significance of CHIP in immune-mediated hematological diseases, such as ITP, is not clearly known. Here we present the preliminary results of a cross-sectional study on adult ITP patients followed at our clinics from 2019 until March 2023. History of any hematological malignancy was an exclusion criterion. An NGS study on PBL was performed by Ion Torrents5, Ion Reporters software 5.2, evaluating mutations in 69 potentially oncogenic genes present in the Oncomine Myeloid Research Assay diagnostic panel. Only mutations with a variant allele frequency (VAF) of 2% were considered, while mutations with VAF > 40% were regarded as potentially germline and discarded. To correlate mutational status with clinical features, a two-tailed Fisher's exact test was used for analysis of dichotomic variables, while a two-sided student's t was used for continuous ones. We included 37 ITP patients (Table 1), 14 of which (38%) had at least one mutation. After exclusion of 4 mutations with VAF > 40%, a total of 17 mutations were considered, affecting 11/37 (30%) patients (NGS-positive). Mutated genes were TET2 (7/17, 41%), DNMT3A (4/17, 18%), SRSF2 (2/17, 12%), and SF3B1, MPL, ASXL1 and NF1 in 1/17 (6%) case each. All patients, except two, had received at least one treatment line (steroids +/- intravenous immunoglobulins), 32 (86%) and 14 (38%) subjects 2 or 3 lines, respectively. Median age of NGS-positive was significantly higher than NGS-negative patients: 73 years, interquartile range (IQR) 68 - 76 vs 62 years, IQR 52 - 70 (p = 0.02). NGS-positive had a slightly lower rate of complete response (CR; PLT > 100 x 10 9/L) after steroid treatment, compared with NGS-negative patients (40% vs 60%, respectively). Among the 9 NGS-positive patients who received thrombopoietin receptor agonists (TPO-RA), only 2 were evaluated before, and the remaining after a median of 2.6 years from TPO-RA start. Considering the 9 patients treated with TPO-RA, NGS-positive had a slightly lower rate of CR than NGS-negative patients (44% vs 79%, respectively). In this respect, we did not find substantial disparities in distribution or VAF of gene mutations between patients who fully responded to TPO-RA and those failing to achieve CR. With the caveat of a cross-sectional analysis in a limited number of cases, these data show the presence of CHIP in 1/3 of multi-treated ITP patients, a frequency similar to that of a much more elderly Italian population >80-year-old (Rossi et al, Blood. 2021), suggesting a possible role of autoimmunity/inflammation and treatment in clonal selection.

A Phase 1a/b Trial of Luxeptinib (CG-806) in Patients with Relapsed/Refractory B-Cell Malignancies or Acute Myeloid Leukemia and Evaluation of New G3 Formulation

INTRODUCTION: Luxeptinib (CG-806; LUX) is an orally active noncovalent kinase inhibitor of Bruton's tyrosine kinase (BTK), wild type and mutant forms of Fms-like tyrosine kinase 3 (FLT3) (including the internal tandem duplicates (ITD), tyrosine kinase domain (TKD), and F691L mutant forms), and growth receptors like KIT, CSF1R, PDGFRα, and TRKs. In prior studies, LUX has been shown to suppress aberrant proliferative signaling in B cell malignancies and acute myeloid leukemia (AML) via regulation of BTK, LYN, SYK, AKT, ERK, and MAPK. LUX is cytotoxic to primary AML cells insensitive to other FLT3 inhibitors and to malignant B-cells insensitive to ibrutinib, at pM and nM concentrations, respectively. AIMS: The primary objectives of these studies are to assess the safety, tolerability, and pharmacokinetics (PK) of LUX and determine recommended phase 2 doses for relapsed or refractory (R/R) AML and B cell malignancy patients. METHODS: In two studies (NCT04477291; NCT03893682), LUX (original formulation, G1) was administered continuously as oral capsules BID in 28-day cycles of ascending cohorts (relapsed or refractory de novo, secondary, or therapy-related AML or higher risk myelodysplastic syndrome (MDS), and relapsed and refractory for B cell lymphoma and chronic lymphocytic/small lymphocytic leukemia). A novel generation 3 (G3) formulation of LUX designed to increase bioavailability was tested at a single-dose (sub-study) for relative bioavailability (RBA), followed by continuous dosing in subsequent R/R AML patients. RESULTS: In the B-cell study (as of 15 th May 2023), LUX has been administered to 36 patients at dose levels from 150 mg to 900 mg BID in patients with a median of 3 lines of prior treatment, with 47.2% having received a BTK-inhibitor. Only one (2.8%) patient had a DLT of hypertension and 14 (38.9%) experienced at least one drug related ≥Grade3 treatment emergent adverse event (TEAE). Two patients (900 mg) are currently on study with no DLT and no ≥Grade 3 related TEAEs. A Follicular lymphoma patient is at cycle 28, and achieved a best response as partial response (PR) with a decrease in lesion size of 76.2%; an SLL patient is at cycle 13, and achieved stable disease (SD) showing a decrease in lesion size of 43.1% (Figure A). The overall best response achieved among the 17 patients who have been on treatment for more than 12 weeks are stable disease (SD) (n=11), partial response (PR) (n=3), minor response (n=2) and complete response (CR) (n=1). As of 5 th June 2023, in the AML trial, a total of 40 patients (16 (40%) FLT3-ITD, 21 (52.5%) FLT3-WT, 2 (5.0%) FLT3-TKD, and 1 (2.5%) unknown mutations) with a median of 3 prior treatments (range, 1 - 10) have been treated with LUX G1 formulation at dose levels from 450 mg - 900 mg BID (n=34) or with 50 mg BID of G3 formulation (n=6). Four (10%) experienced drug related SAE and 7 (17.5%) had a drug related grade ≥3 TEAEs. The most common related TEAEs were lymphocyte count decrease, platelet count decrease, and anemia (n=2; 5% patients each). One (2.5%) patient at 450 mg dose, reported complete remission without minimum residual disease (CRmrd) and remained on study for 56 weeks. In the RBA sub-study, G3 (50 mg) produced comparable exposures to G1 (450-900 mg range) (Figure B) and was, therefore, selected as the starting dose for use in the R/R AML study. Six patients were treated with a continuous dosing of 50 mg BID G3; with plasma levels of 274 ng/mL and 195 ng/mL LUX observed by the end of C1D15 and C1D22 respectively. No drug related Grade ≥3 TEAEs or DLTs were observed in 50 mg BID G3 LUX treated patients; with no new safety signals observed for the G3 formulation. Based on these findings and expected exposures for higher dose levels, the cohort safety review committee has approved escalation of G3 dosing to 200 mg BID at which dosing is ongoing. CONCLUSIONS: LUX has a favorable safety profile in patients at all tested dose levels, for multiple cycles, for both studies. Antitumor activity was observed in a heavily pretreated relapsed AML patient and in multiple B-NHL subtypes and CLL/SLL patients including several with prior ibrutinib exposure. Continuous dosing of patients with R/R AML and Higher-Risk MDS with the G3 formulation is ongoing; with updated clinical data (200 mg dose level) to be presented at the meeting.

Improved Overall Survival Among Luspatercept Responders and Predictors of Response

Introduction Luspatercept (luspa) is a first-in-class erythroid-maturation agent approved for red blood cells transfusion dependent (RBC-TD) lower risk myelodysplastic syndrome (LR-MDS) with ring sideroblast (RS) based on MEDALIST clinical trial. We aimed to explore impact of luspa on overall survival (OS) and predictors of response in a large cohort of pts treated with luspa, collected from Moffitt Cancer Center (MCC) and from Fondazione Italiana Sindromi Mielodisplastiche (FISiM). Methods We evaluated all pts with LR-MDS-RS treated with luspa from MCC cohort since FDA approval, and from a multicenter observational trial of FISiM for pts treated on a compassionate use program . Baseline RBC transfusion burden (TB) was defined as: non-transfusion dependent (NTD) (0 units in 8 weeks prior luspa), low TB (LTB) (1-5 units/8 weeks ) and high TB (HTB) (≥ 6 units/8 weeks). A hematological response (HI) was defined as an (i) objective Hgb increase of > 1.5 g/dl in NTD, and (ii) RBC-TI with Hgb increase of 1.5 g/dl, or RBC-TI without Hgb 1.5 g/dl increase, or >50% reduction in RBC TB among RBC-TD. Somatic mutation (MT) data were available for 137 pts. Results Between January 2020 and March 2023, 331 pts were treated with Luspa (Table-1). The median age was 69 years; 308 pts (93%) had MDS-RS, 86,1% were intermediate, low or very low risk MDS by R-IPSS and 82% (105/128) were moderate low (ML), low (L) or very low (VL) by IPPS-M. SF3B1 MT was detected in 86.3% (120/139) with a median VAF of 37.7. The mean Hgb level was 7.97 g/dl and 93.7% were RBC-TD. Majority had prior erythroid stimulating agents (ESA) (93.6%). In the MCC cohort 42.9% (52/121) had prior hypomethylating agents (HMA) therapy, and 31.4% (38/121) had prior lenalidomide (len). With a median follow up of 14.6 mos from starting luspa treatment, the median OS was not reached (NR) among responders to luspa compared to 24.5 mos for non-responders (p <.001) (Figure-1). The median OS benefit was more pronounced among pts with RBC-TI and Hgb> 1.5 g/dl increase compared to other categories of response. In the NTD group at baseline, the median OS among luspa responders was NR compared to 22.7 mos among non-responders (P< .001). In the LTB group at baseline median OS was NR as well among luspa responders compared to 29.9 mos in non-responders (p=.002) and finally among HTB group at baseline, the median OS among luspa responders was 35.4 mos compared to 21.2 mos in non-responders (p=.007). In multivariable analysis adjusting for IPSS-M and baseline RBC-TD, response to luspa was independently associated with improved OS, HR .39 (95% CI .18-.83), p= .015 The overall HI rate to luspa was 40.6% (134/330) (Table-1), 85% of pts needed dose escalation, HI correlated with baseline RBC-TB where 80% (16/20) NTD, 60.2% (65/108) LTB and 41.8% HTB (77/184) achieved HI respectively, p< .001. By IPSS-M, there was a trend for lower HI with higher risk disease (100% in VL, 60.3% in L, 36.7% in ML, 56.3% in MH, 16.7% in H risk pts, p=.051). There was a mild trend for higher response among SF3B1 MT pts compared to wild type, 54% (64/119) versus 42% (8/19), p=.34.The segregation of SF3B1 MT cases into three independent groups based on IPSS-M, showed that HI rate was better in SF3B1 β ( SF3B1 and any gene from BCOR, BCORL1, NRAS, RUNX1, SRSF2 or STAG2) and SF3B1 α (as any other mutant) than SF3B1 5q(concomitantpresence with isolated del5q): 50% (7/14), 58.8% (57/97), and 0% (0/5) respectively, p=.03. Among SF3B1 5qpts, 4 had been treated with len before luspa and only 1 had achieved an HI with prior len. Among pts with SF3B1 MT, we observed a trend for higher response in pts with the hotspot K700E, 62.7% (37/59) vs 47.4% (27/57) in non-K700E, p=.097. In pts with SF3B1 MT, divided by median VAF, we observed a trend for better HI with VAF was >38, 63.5% (33/52) vs 45.3% (24/53), p=.062. Among responders, the median duration of response was 14.1 mos. As of last follow up, 85% pts (191/224) discontinued treatment. Reason of discontinuation was lack of response in 126 pts, loss of response in 26 patients and adverse events in 6 pts. The most common reported adverse events were fatigue (n=10), GI symptoms (n=4), shortness of breath and arthralgia (1 each). Conclusions Our RWD in the largest luspa treated cohort demonstrates OS benefit to luspa response. Low baseline RBC-TB dependency, lower risk IPSS-M, SF3B1 MT, SF3B1-K700E mutation and SF3B1 α co-mutations correlated with higher response rates. Our data emphasizes the impact of RBC-TI in LR-MDS.