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Background Venetoclax + hypomethylating agent (Ven-HMA) therapy results in favorable response rates (CR/CRi 66%) and overall survival (OS; median 14.7 months) in unfit patients with newly-diagnosed acute myeloid leukemia (ND-AML; N Engl J Med 2020;383). However, there is substantial heterogeneity in individual patient outcomes based on response to treatment. The objective of the current study was to develop a genetic risk model to predict survival outcome in treatment responders and non-responders, analyzed separately, and also account for allogeneic stem cell transplant (ASCT). Methods Treatment-naïve AML patients receiving Ven-HMA, outside of a clinical trial, at the Mayo Clinic, USA (MN, AZ, FL) were retrospectively recruited. Molecular studies (48-gene panel) were performed by next-generation sequencing. Response was assessed according to the 2022 European LeukemiaNet (ELN) criteria (Blood 2022;140). Standard statistical analyses were performed using JMP Pro (Version 17.0.0). Results 400 ND-AML patients (median age 73 years, 64% male, 60% de novo) received Ven-HMA. ELN cytogenetic risk included favorable 2%, intermediate 60%, or adverse 38%. Mutations involved TP53 in 26%, TET2 19%, RUNX1 19%, SRSF2 18%, ASXL1 18%, DNMT3A 15%, K/NRAS 13%, NPM1 12%, IDH2 12%, FLT3-ITD 10%, IDH1 7% and DDX41 in 4% of informative cases. 153 (38%) patients achieved CR, 94 (24%) CR with incomplete count recovery (CRi), resulting in CR/CRi in 247 (62%) patients. CR/CRi rates were higher with NPM1 (86% vs 59%), IDH2 (77% vs 60%), and DDX41 mutations (93% vs 61%) and lower with TP53 (45% vs 67%), FLT3-ITD (41% vs 64%), RUNX1 (49% vs 65%) mutations and adverse karyotype (48% vs 71%), with all retaining significance in multivariable analysis. CR/CRi rate was highest (87%) in 75 patients with one or more favorable mutations (NPM1, IDH2, DDX41) and no unfavorable mutation (TP53, FLT3-ITD, RUNX1). CR/CRi rate was lowest in 171 patients with at least one unfavorable mutation and no favorable mutation (44%; p<0.01). After a median follow up of 10.5 months (0.5-66), 105 relapses (43% of patients in CR/CRi), 248 (62%) deaths and 65 (16%) ASCT were documented. Univariate analysis for transplant-censored OS disclosed superior survival in patients achieving CR/CRi (median 21 vs 3.6 months; HR 5.4, 95% CI 4.1-7.1). Among patients achieving CR/CRi, IDH2 mutation was associated with superior (median not reached vs 20.5 months) and male gender (median 17.6 vs 29.2 months), TP53 mutations (median 11.9 vs 24.3 months) and adverse karyotype (median 12.6 vs 29.4 months) with inferior survival; multivariable analysis resulted in HRs (95% CI) of 2.1 (1.3-3.4) for male gender, 2.1 (1.2-3.8) for adverse karyotype, and 2.5 (1.1-5.7) for absence of IDH2 mutations. Male gender did not show an association with karyotype, or TP53 mutations (p>0.1). Accordingly, an HR-weighted genetic risk model was generated with assignment of one point each to male gender, adverse karyotype, and absence of IDH2 mutation: high risk = 3 risk factors (n=38; median 9.6 months; 3-year survival 0%); intermediate risk = 2 risk factors (n=129; median 22 months; 3-year survival 38%); and low-risk = ≤1 risk factor (n=78; median not reached; 3-year survival 69%; p<0.01). In patients bridged to ASCT (n=60), post-transplant survival was inferior in the presence of ≥ 2 risk factors (n=42; median 46 months) vs. ≤1 risk factor (n=18; median not reached; p=0.1). In patients not achieving CR/CRi, risk factors for OS included male gender (median 3.4 vs 6.1 months), adverse karyotype (median 3.3 vs 4.5 months) and TP53 mutation (median 3.1 vs 4.5 months) while those with IDH2 mutations lived longer (median 8.4 vs 3.4 months). In multivariable analysis, HRs (95% CI) were 1.9 (1.3-2.9) for male gender, 2.0 (1.4-2.9) for adverse karyotype, and 2.1 (1.1-4.3) for absence of IDH2 mutations. OS was shortest for non-responders harboring 3 risk factors (n=45; median 3 months; 1-year survival 0%) and longer for those harboring two (n=80; median 6 months, 1-year OS 15%) or ≤ 1 risk factor (n=25; median 14 months; 1-year OS 56%; p<0.01). Conclusion The current study describes a molecular profile for predicting response to Ven-HMA in ND-AML and also introduces a novel approach to survival prediction that considers treatment response as the starting point. In both responders and non-responders, male gender and adverse karyotype were identified as unfavorable and IDH2 mutation favorable risk factor for OS.

Background Acute myeloid leukemia (AML) with TP53 mutation (m) has poor outcomes even in the contemporary era with median overall survival (OS) of 6-9 months. The only factor that has been shown to improve outcomes is allogeneic hematopoietic cell transplantation (allo-HCT) (Badar et al AJH 2022; Leukemia 2023). However, the role of allo-HCT for TP53-m AML continues to be a matter of debate given high rates of relapse after allo-HCT particularly in TP53-m AML with complex cytogenetics (CG). We used the COMMAND consortium database to investigate the factors that influenced physician's decision for allo-HCT in TP53-m AML. Method We conducted a multicenter observational study in collaboration with 7 U.S. academic centers under COMMAND consortium. We reviewed electronic medical records of 369 TP53-m AML patients to analyze reasons for not pursuing allo-HCT including refractory disease, donor availability, advanced age/co-morbidities, physician perspective on ineffectiveness of allo-HCT in improving outcome and patient's decision. Diagnostic criteria for TP53 allelic state were according to the International Consensus Classification (ICC) (Blood 2022; 140:1200). Next-generation sequencing and cytogenetic studies were performed according to institutional standard protocols. Results The median age at diagnosis was 68 years, with 222 (60.5%) patients being male. The majority of patients were diagnosed with de novo AML 179 (48.8%), followed by secondary AML (sAML) in 103 (28%) patients, and therapy-related (t)AML in 85 (23.2%) patients. Ninety-four percent of evaluable patients had complex cytogenetics (CG) and 192 (52%) had multi-hit TP53-m. One-hundred forty-seven (42%) patients received intensive chemotherapy (CPX 351 [66 (44%)], 7+3 [78 (53%)]), while 205 (58%) patients received low-intensity regimens including hypomethylating agents (HMA) plus venetoclax (137 [66%]) and HMA +/- investigational agents (68 [33%]). The rate of complete remission (CR)/CR with incomplete count recovery (CRi) was 34.4% and overall response rate (CR/CRi + partial remission [PR] + morphologic leukemia free state [MLFS]) was 52%. Forty-seven (13%) patients received allo-HCT in CR1 and 17 (5%) patients received allo-HCT in CR2. Of the 294 patients for whom data on allo-HCT decision-making was available, the most common reason for not proceeding to allo-HCT was refractory disease in 126 (43%) patients. Other significant reasons included advanced age/comorbidities (n=78 [30.6%]), physician recommendation (n=7 [2%]), patient's decision (n=24 [9.4%]), and patient relocation or changing healthcare providers (n= 9 [3.5%]). Two (0.4%) patients had no suitable donor available for allo-HCT. Amongst the 7 patients for whom allo-HCT was not pursued due to physician's decision, the median age of the patients was 69 years (R, 59-70), 3 (25%) patients had sAML, and all of them had multi-hit TP53-m associated with complex CG. Six out of seven (86%) patients received HMA plus venetoclax and 1 (14%) patient received HMA-based induction. Six patients achieved CR/CRi after induction and 1 patient had partial remission. The median survival of these patients was 11 months (R, 10.7-11.3), eventually all patients died from progressive AML. Conclusion Our survey suggests that the primary reason for not proceeding with allo-HCT was refractory disease, underlying the difficulty in achieving the disease control needed for allo-HCT. There is an urgent need for better frontline therapies tailored specifically for TP53-m AML, along with refined patient selection criteria to better identify candidates who would benefit most from allo-HCT to potentially improve their long-term outcomes.

Background: Hypomethylating agent (HMA) and venetoclax (VEN) therapy is a standard of care frontline treatment of acute myeloid leukemia (AML) amongst patients (pts) ineligible for intensive therapy. Despite its convenient flat dose, oral nature, and static excretion irrespective of body weight (wt), VEN has a large, variable volume of distribution and extensive protein binding (Yang, Molecules, 2022). Body mass index (BMI) is a more accurate, albeit imperfect, indicator of body fat that has not been evaluated as an independent predictor of differential VEN exposures and clinical outcomes. We sought to evaluate this possibility amongst pts treated with frontline HMA+VEN in a multi-center, real-world, retrospective study. Methods: We conducted a multi-center, retrospective study through four US academic centers in the Consortium on Myeloid Malignancies and Neoplastic Diseases (COMMAND). 368 pts treated with frontline HMA+VEN from 6/2016-8/2023were evaluated based on BMI within 30 days of induction. Responses were defined by European LeukemiaNet (ELN) 2022 criteria. Pearson's chi-squared test and Wilcoxon rank-sum test were used for comparison between groups. The Kaplan-Meier method and multivariable Cox regression model were applied to overall survival (OS). Continuous variables were summarized as a median with interquartile range (IQR), and categorical variables were reported as a frequency (percentage). Results: The median age was 75 (IQR: 70-79) years, 58% were male, and 76% were white. 107 (29%) had a normal BMI of 18-25 kg/m2, 141 (38%) were overweight (BMI 25-30 kg/m2), and 120 (33%) were obese (BMI >30 kg/m2). There were no significant differences in baseline pt-, disease-, and treatment-specific factors when comparing pts with normal wt to BMI >25.The cohort was enriched for complex karyotype and TP53-mutated disease (27% and 32%, respectively), with 73% categorized as adverse risk by ELN 2022. There was no difference in 30-, 60-, and 90-day mortality rates (6-8%, 14-18%, 19-29%, respectively) by BMI group. Complete remission (CR/CRi) rate was 50% overall and was not impacted by BMI (41%, normal wt; 55%, overweight; 52%, obese) (p=0.10). Overall response rate (ORR) (CR/CRi/MLFS) was 59% overall and differed by BMI groups (50%, normal wt; 66%, overweight; 58%, obese) (p= 0.047). The median OS was 6.6 months for normal wt, 13.7 months for overweight, and 8.3 months for obese pts, and not significantly different when comparing normal to overweight (p=0.052) or obese pts (p=0.756). In multivariable analysis, the effect of BMI varied by the composite remission rate used. Overweight was borderline significantly associated with higher likelihood of achieving CR compared to normal wt (odds ratio [OR] 1.98, 95% confidence interval [CI] 0.99-4.03; p=.056), whereas obesity was not (OR 1.78, CI 0.86-3.74; p=.13). Other co-variates with a significant association with achieving CR included diagnosis of secondary AML (sAML) (OR 0.37, CI 0.18-0.74; p=.006) and presence of IDH (OR 2.81, CI 1.30-6.15; p=.009), ASXL (OR 0.39, CI 0.15-0.96; p=.046), TET2 (OR 2.43, CI 1.17-5.09; p=.02), and DNMT3A (OR 2.37, CI 1.19-4.78; p=.02) mutations. There was a trend towards higher likelihood of achieving CR/CRi for both overweight (OR 1.74, CI 0.92-3.32; p=.09) and obese pts (OR 1.88, CI 0.96-3.74; p=.07). Diagnosis of sAML and presence of TET2, ASXL, and DNMT3A mutations no longer had a significant association with achieving CR/CRi, while IDH mutations maintained an association (p=.01). None of these variables demonstrated a significant impact on ORR (inclusive of MLFS) except overweight (OR: 1.99, CI 1.06-3.80; p=.03) and sAML vs de novo (OR: 0.53, CI 0.29-0.99; p=.047). In multivariable logistic regression, higher ECOG score was associated with risk of early mortality within 60 (p=.01) and 90 (p=.01) days, but not 30 days. sAML vs de novo associated with higher 90-day mortality, presence of NPM and TP53 mutation associated with higher 30-day mortality, and cytogenetic risk associated with higher 60- and 90-day mortality. Conclusions: This multi-center, real-world study demonstrates that BMI may not have a linear effect on response to frontline HMA+VEN, with some indication of negative impact at both lower and higher BMI categories. However, additional dedicated studies are needed to determine if differences in BMI is associated with altered drug exposure as an explanation for these differences.

Background Venetoclax + hypomethylating agent (Ven-HMA) therapy has demonstrated improved outcomes in elderly/unfit patients with newly-diagnosed acute myeloid leukemia (ND-AML) (N Engl J Med 2020;383). However, ~50% of patients who respond to Ven-HMA, eventually relapse (Am J Hematol 2024;99). In the current study we examined the prognostic contribution of gene mutations, karyotype, measurable residual disease (MRD) status and clinical risk factors for relapse in patients with ND-AML treated with Ven-HMA therapy. Methods Our study population of ND-AML was retrospectively recruited from Mayo Clinic (MN, AZ, FL), after institutional review board approval and based on documentation of complete remission with/without count recovery (CR/CRi) following Ven-HMA therapy. Relapse-free survival was determined from the time of remission to relapse or last follow-up. Survival analysis was censored for transplant. The 2022 European LeukemiaNet (ELN) criteria was used to assign cytogenetic risk and classify treatment response (Blood 2022;140). Standard statistical analyses were performed using JMP Pro (Version 17.0.0). Results 247 ND-AML patients treated with Ven-HMA (median age 73 years, 62% male, 64% de novo) who achieved CR (n=153), or CRi (n=94) were included. MRD by multiparameter flow cytometry (sensitivity 0.01%) performed at the time of CR/CRi, was negative in 117 (70%) of 166 informative cases. ELN cytogenetic risk categories at diagnosis included favorable 2%, intermediate 69%, or adverse 29%. Mutations involved TET2 21%, SRSF2 21%, TP53 19%, ASXL1 18%, DNMT3A 18%, NPM1 17%, IDH2 15%, RUNX1 15%, K/NRAS 12%, IDH1 8%, FLT3-ITD 7%, and DDX41 in 6% of informative cases. Relapse was documented in a total of 99 (40%) patients who achieved CR (39%) or CRi (41%) after a median remission duration of 6 months (1-31). Patients that relapsed within the first-year vs those that did not, were more likely to be males (75% vs 55%), MRD positive (44% vs 24%), and harbor TP53 mutations (23% vs 16%). Univariate analysis for RFS identified male gender (12 vs 29 months; p=0.02), secondary AML (10 vs 21 months; p<0.01), adverse karyotype (9 vs 22 months; p<0.01), TP53 mutations (6 vs 18 months, p<0.01) and MRD positive remission (13 months vs not reached; p<0.01) as risk factors for relapse; on the other hand, IDH2 mutations (not reached vs 15 months; p<0.01) were associated with a lower risk of relapse. Multivariable analysis confirmed male gender (HR 2.2), TP53 mutations (HR 3.0) and MRD positive remission (HR 1.7) as unfavorable predictors of relapse. Subsequently, in a three-tiered relapse prediction model, RFS was significantly inferior in the presence of three risk factors (male gender, TP53 mutations, MRD positive remission) (n=10, median 4 months), vs two (n=34, median 10 months) vs ≤ 1 risk factor (n=122, median 31 months) (p<0.01); 1-year cumulative incidence of relapse was 100%, 56%, and 26% in the presence of three, two and ≤ 1 risk factors, respectively. 50 of 99 (65%) patients received salvage therapy which included cladribine-cytarabine-Ven (n=19), intensive induction chemotherapy (n=9), FLT3 inhibitors (n=5), Ven-HMA-FLT3 inhibitor (n=1), IDH1/2 inhibitors (n=5), glasdegib-cytarabine (n=4), gemtuzumab (n=3), lenalidomide (n=1), or investigational therapies (n=3); in addition, Ven-HMA was resumed in 14 patients in whom treatment had been discontinued for a median of 5 months (2-12). Overall, 20 (31%) of patients achieved second CR/CRi and response rates were similar with intensive vs less intensive therapy (CR/CRi; 44% vs 29%; p=0.37). Median follow up after relapse was 3.4 months (1-66), during which 73 (74%) deaths, and 4 (5%) ASCT were recorded. Median transplant-censored survival was 4.2 months (1-year; 22%), and inferior in patients with adverse karyotype (median 4.6 vs 3.4 months; p=0.02), and TP53 mutations (3.6 vs 4.4; p=0.11); on the other hand, male gender (3.5 vs 6.8 months; p=0.51), MRD positive remission (4.6 vs 4.2; p=0.56), and IDH2 mutations (6.7 vs 4.2; p=0.28), did not influence post-relapse survival. Conclusions The current study identifies male gender, TP53 mutations, and MRD status as powerful predictors of relapse and proposes a relapse prediction model for ND-AML patients receiving Ven-HMA therapy. Furthermore, relapse following Ven-HMA was associated with uniformly poor outcomes, regardless of salvage treatment strategy.

Introduction: Acute myeloid leukemia (AML) has been considered by many to be an oncologic emergency often leading to hospital admission for expeditious evaluation and treatment. Previous studies reported that time from diagnosis to treatment (TDT) does not impact outcomes (Sekeres, Blood, 2009), (Bertoli, Blood, 2013), (Rollig, Blood, 2020), however these analyses were restricted to intensively treated and/or non-United States (US) patients (pts). We report on a multi-center, retrospective analysis of TDT in adults with newly diagnosed AML receiving Hypomethylating agent (HMA) + venetoclax (Ven) using real-world data from the COMMAND. Methods: Eight US academic medical centers with AML expertise performed a review of adult pts within their center treated with HMA+Ven for newly diagnosed AML. TDT was defined as days from diagnosis of AML to initiation of treatment with HMA+Ven. Cytoreduction with hydroxyurea or leukapheresis was included to control for the effects of severity of presentation on TDT. The primary outcome was impact of TDT on overall survival (OS) (defined as date of diagnosis to date of death). TDT was treated continuously for time-to-event analyses. Secondary outcomes included measurable residual disease (MRD) by flow cytometric analysis (sensitivity <0.1%), complete response (CR), complete response with incomplete count recovery (CRi), defined by European LeukemiaNet (ELN) 2022 Guidelines (Dohner, Blood,2022), and early mortality (death within 30 and 60 days of initiation of HMA+Ven). Pre-planned subgroup analyses included those based on disease biology (FLT3 ITD, IDH1/2, TP53 mutation, ELN 2022 risk), HMA used (azacitidine vs decitabine) and age (<75 vs ≥75 years). For those analyses where TDT was significant in univariable analysis (P=0.1), multivariable analysis was conducted controlling for the following: ECOG performance status (PS), age, receipt of cytoreduction, ELN 2022 risk, and presence of individual pathogenic variants detected on broad myeloid gene next generation sequencing panels used at each institution. All analyses were conducted by a central statistician using RStudio statistical package. Results: 488 pts were included in the analysis. Median age was 76 (interquartile range: 70-80) and the majority of pts had an ECOG PS of 0 or 1 (56%). Most pts (67.6%) had adverse risk with 9.4% and 18.6% of pts having favorable and intermediate risk disease by ELN 2022, respectfully. The most common mutations identified were TP53 (27.5%), IDH1/2 (19.3%), NPM1 (16.4%), DNMT3A (16.8%), ASXL1 (15.4%), and FLT3-ITD (13.7%). Twenty-eight percent of pts received cytoreduction prior to initiation of HMA+Ven. Azacitidine+Ven was the most common regimen utilized (53.9%). Median number of cycles of HMA+Ven was 3 (IQR: 1-6). MRD (-) CR, MRD (+) CR, and CRi was achieved in 21.5%, 10.5%, and 16.4% of pts after one cycle of HMA+Ven. Median OS for the cohort was 10.4 months (95% CI: 9.4-12.6). Median TDT for the cohort was 9 days (IQR: 5-17). In univariate Cox model, longer TDT was associated with improved OS (HR: 0.989, 95% CI: 0.981 to 0.998; p = 0.013). In multivariable analysis, longer TDT was still associated with improved OS (HR: 0.987; 95% CI: 0.973-0.999; p=0.049). TDT and presence of bZIP in-frame CEBPA mutations were the only factors associated with improved OS, while ECOG PS of 2 or 3-4, when compared to ECOG PS=0 (p=0.035 and 0.0002, respectively) and therapy-related AML (p=0.002), were associated with worse OS. Notably, ELN 2022 risk and IDH1/2 or NPM1 mutation status did not impact OS. Discussion: In this real-world, multi-center, US-based analysis of pts with newly diagnosed AML treated with HMA+Ven we show that longer TDT is associated with improved OS even when controlling for severity of presentation, ELN 2022 risk score, ECOG PS, and age. This finding is consistent with data in pts treated with 7+3. Similar to results published in an electronic medical record-based analysis out of Germany (Baden, Haemotologica, 2024) in pts treated with lower-intensity Ven regimens, our results show that pts with newly diagnosed AML eventually treated with HMA+Ven are best served with a complete appraisal of disease biology and treatment planning before initiation of induction therapy. Given the consistent negative impact of ECOG PS and the findings of our study, future consideration for potential patient optimization strategies to improve ECOG PS prior to therapy initiation are warranted.

Introduction: Based on a donor versus no-donor analysis, UKALLXII/E2993 showed a survival benefit for adults with acute lymphoblastic leukemia (ALL) who underwent allogeneic hematopoietic cell transplantation (alloHCT) in first complete remission (CR1) compared to consolidation/maintenance chemotherapy alone. The follow-up phase 3 E1910 trial (NCT02003222) randomized BCR::ABL1-negative B-lineage ALL patients (pts) aged 30-70 years in measurable residual disease (MRD)-negative CR1 after intensification to conventional chemotherapy (CC) +/- blinatumomab (blin) and demonstrated significantly improved overall survival (OS) with blin (Litzow, NEJM 2024). The current exploratory subgroup analysis evaluates outcomes of MRD-negative pts randomized on E1910 who underwent alloHCT on trial. Methods: Among pts enrolled on E1910, pts in MRD-negative CR1 by 6-color flow cytometry after intensification who were randomized to CC +/- blin and subsequently underwent alloHCT were identified. We compared baseline characteristics, MRD status post induction, relapse-free survival (RFS) and OS using the Kaplan-Meier method and the two-sided log-rank test and Cox model. A multivariable analysis was performed with alloHCT included as a time-varying covariate as well as a landmark analysis comparing the outcome of pts with unfavorable risk on the CC + blin arm who underwent alloHCT versus those who did not. Results: Of 224 MRD-negative randomized pts, 44 underwent alloHCT on trial: 22 in each arm. The median time from randomization to transplant was 3.2 months (mos). The median follow-up from initial registration was 57.8 mos. Baseline demographics including age (median 55 years), gender (53% male), race (89% white) and ethnicity (89% non-Hispanic/Latino) were equally distributed. Compared to CC + blin, the median peripheral blood white cell (WBC) count and blast percentage at diagnosis were higher in the CC arm at 6,640 vs 3,740/uL and 55 vs 9%, respectively, while median marrow blast percentage and overall unfavorable risk as defined in E1910 (55% vs 64%) were similar. Of the 44 MRD-negative pts who proceeded to alloHCT on study, 77% in the CC arm and 64% in the CC+ blin arm were MRD-negative after induction. Myeloablative conditioning was given to the majority of pts (68% CC arm and 73% CC+blin arm) and the most common graft versus host disease prophylaxis was tacrolimus-based on both arms. Among the 44 pts who underwent alloHCT, the observed hazard ratio (HR) comparing relative risk of death between pts randomized to CC+blin or CC only was 0.59 (95% CI: 0.12-2.11) with a 3-year OS rate of 82% versus 71% and the HR comparing relative risk of relapse/death was 0.52 (CI: 0.15-1.79) with a 3-year RFS rate of 82% versus 67%. For patients with unfavorable risk, 3-year OS and 3-year RFS in each treatment arm were both 71% versus 65%. Among 50 pts with unfavorable risk in MRD-negative CR after intensification who were randomized to CC + blin, a landmark analysis performed at 5 mos post randomization showed 3-year OS and RFS rates of 71% versus 90% and 71% versus 86% between the 14 pts who underwent alloHCT and those who did not, respectively. Receipt of alloHCT was a time-varying covariate in a multivariable analysis with gender, WBC count, platelets, hemoglobin, peripheral blood blasts, bone marrow blasts, performance status, and combined molecular risk category. Age, CD20 status, rituximab use, and intention to receive alloHCT were used as stratification factors. In the entire cohort of MRD-negative pts who were randomized, there was a significant association between improved OS and the receipt of CC+blin vs CC alone (HR 0.46, 95% CI: 0.26 - 0.82; p=0.009), better performance status of 0-1 vs ≥2 and favorable vs unfavorable risk ALL. In contrast, the receipt of alloHCT had no significant effect on OS (HR 1.00, 95% CI: 0.49 - 2.01). Conclusions: Within the constraints of small numbers, this exploratory subgroup analysis demonstrates that in pts with newly diagnosed BCR::ABL1-negative B-ALL treated on E1910 who achieved MRD-negativity after intensification, alloHCT outcomes did not appear to be different with or without blin in consolidation. In a multivariate analysis of all MRD-negative pts, receipt of blin but not alloHCT was associated with improved OS. Further investigation is warranted to characterize the relative benefit of blinatumomab in pts receiving alloHCT in frontline consolidation.

DDX41 MT Germline Predisposition Syndrome (GPS) is the most common adult GPS for myeloid neoplasms (MN), including MDS and AML. Although there have been reports of non-myeloid neoplasms, particularly lymphoid malignancies, in DDX41MT-GPS, these occurrences are infrequent and poorly characterized. We carried out this study in a large cohort of DDX41MT-GPS patients to address this deficiency. Following IRB approval, we retrospectively analyzed our database of 174 patients with DDX41MT-GPS to determine the rates of non-myeloid malignancies. Our previous data revealed that certain DDX41MT genotypes classified as variants of uncertain significance (VUS) exhibit a similar phenotypic spectrum to those classified as pathogenic (Badar et al Hematologica). Consequently, we included all these variants in our analysis. The median age of the cohort was 68.6 yrs (range, 13-4-93.4); 66% (n=114) male, 93% (n=162) Caucasian, with a median follow-up of 1.4 yrs (range, 0.03-5.6) from DDX41MT-GPS detection. The cohort included 34 (19.5%) asymptomatic carriers, 17 (9.8%) with clonal hematopoiesis (CH) or clonal cytopenias (CCUS), and 123 (70.7%) with MN. Eighteen (10%) patients had a lymphoid neoplasm (78% male, 100% Caucasian), with a median age at lymphoid neoplasm diagnosis of 67.7 yrs (range, 12.2-85.9). The most common lymphoid neoplasm was chronic lymphocytic leukemia (CLL) seen in 2.3% (n=), followed by follicular lymphoma (FL) and acute lymphoblastic leukemia (ALL) present in 1.7% each (n=3; 1 T-ALL and 2 B-ALL: 1 Ph+ and1 Ph-like). Additionally, there was 1 patient each with monoclonal B cell lymphocytosis (MBL), Waldenstroms macroglobulinemia , peripheral T cell lymphoma , large granular lymphocytic leukemia, and marginal zone lymphoma. Germline genotypes were classified as pathogenic in 50% (n=9, D140Gfs*2 x2, K331del, M1I x3, M316Dfs*31, P258L, Y340N) and VUS in 50% (n=9, E426K, E69D, G313D, K184R, P206A, P70S, Q246E, R164W, c.572-3T>C. Among these 18, 9 (50%) patients had co-existing myeloid disorders (CCUS x3, MDS x5, AML x1), and 5 (27.8%) patients were later diagnosed with therapy-related myeloid neoplasms (TMN) at a median of 5.9 yrs (range,1.6-38.7) after lymphoid neoplasm diagnosis and treatment. Seven (4%) patients had plasma cell dyscrasias (PCD; 3 with monoclonal gammopathy of undetermined significance(MGUS) and 4 with multiple myeloma (MM)); 57% (n=4) were male, with a median age of 61.3 yrs (range, 41.4-83.8) at PCD diagnosis. Subtypes of MGUS included IgG Kappa (n=2) and IgG Lambda (n=1), subtypes of MM included IgG Kappa (n=2), IgA Kappa (n=1), and Kappa light chain only (n=1). DDX41MT-GPS genotypes were pathogenic in 28.6% (n=2, G67Vfs*13, G313S) and VUS in 71.4% (n=5, A555T, R164W, Q246E x2, M307T). All patients with MM (n=4) received an autologous stem cell transplant, with 3 (75%) being subsequently diagnosed with a t-MN; median 3.6yrs after PCD diagnosis (range, 3.2-12.3). Seventeen percent (n=31) had visceral malignancies; 2.8% (n=5) having >1malignancy, 61% (n=19) male, 93.5% (n=29) Caucasian and 6.5% (n=2) Hispanic. Prostate cancer was most common (n=8, 4.6%), followed by breast (n=7, 4.0%), colon (n=5, 2.9%), squamous cell carcinoma (n=4, 2.3%, 3 of the head/neck and 1 of the leg), bladder (n=4, 2.3%), testicular (n=3, 1.7%), gynecologic (n=3, 1.7%), lung (n=2, 1.2%), thyroid (n=1, 0.6%) and pancreatic neuroendocrine tumor (PNET, n=1, 0.6%), respectively. The median age at first solid tumor diagnosis was 62.4 yrs (range, 10.9-81.9). DDX41MT-GPS was pathogenic in 64.5% (n=20, D140Gfs*2 x3, E113Kfs*14, G67Vfs*13, I396T, L283Cfs*21, M1I x4, M316Dfs*31 x2, p.M1?, P258L, Q368*, Q41* x2, R159*, R311*) and VUS in 35.5% (n=11, D30Y, H203Y, I215L, I337V, M155I, p.?, S289L, T13I, V318G, A555T). Of the 31 patients with visceral malignancies , 51.6% (n=16) were diagnosed with t-MN at a median of 4.9 yrs (range, 1.1-34.3) after malignancy diagnosis. While DDX41MT-GPS are clearly associated with an increased risk of myeloid neoplasms, we demonstrate potential associations with other neoplasms, especially lymphoproliferative disorders (10%). We for the first-time report associations with PCD (4%) and visceral malignancies (17%) and also highlight a worrisome trend for t-MN in DDX41MT-GPS treated with genotoxic agents. Given limitations of a retrospective analysis, this study underscores the need for a comprehensive natural history study in patients with DDX41MT-GPS .

Background: Inotuzumab Ozogamicin (InO) is an antibody-cytotoxin conjugate with high activity in B-cell acute lymphoblastic leukemia (B-ALL). InO targets the B-cell surface protein CD22, which is expressed in most B-ALL cases, albeit with great variability in expression levels. Emerging evidence suggest that this variation is associated with the stage of leukemia differentiation arrest [PMID: 21348573]. However, the exact relationship between CD22 expression and leukemia sensitivity to InO, particularly in the context of leukemia developmental state, remains unclear. Furthermore, our understanding of the molecular mechanisms regulating CD22 transcription in B-ALL is still incomplete. Methods: To comprehensively investigate the genomic basis of variability in leukemia CD22 expression and thus B-ALL sensitivity to InO, we performed a multi-omic characterization of 196 primary human B-ALL samples, using whole transcriptome sequencing (RNAseq), assay for transposase-accessible chromatin with sequencing (ATAC-seq), coupled with ex vivo profiling of InO sensitivity. Additionally, genomic editing studies were performed in Nalm6 and REH B-ALL cell lines, and patient derived xenograft (PDX) models were used for in vitro and in vivo validations. Results: Applying digital cytometry to leukemia bulk RNAseq data to infer the B-ALL developmental state, we found that blast cells with early Pre-pro-B-like signature had low levels of CD22 expression and were resistant to InO. As B-cell differentiation is controlled by stage-specific transcription factors (TFs), we performed a targeted CRISPR library screen of 1,639 TF genes and identified EBF1 as a key activator of CD22 expression (FDR=7.1x10-4). In primary B-ALL samples, EBF1 expression was significantly correlated with CD22 expression (R=0.69, P<0.0001) and leukemia response to InO (measured as LC50, R=-0.42, P<0.0001). In addition, TF footprint analysis of leukemia ATAC-seq data identified EBF1 as the most differentially activated TF comparing InO-sensitive and -resistant B-ALL cases (P=8x10-174). Blocking the EBF1 binding sites within the CD22 promoter by CRISPR interference resulted in a 50-fold and 49-fold decrease in cell surface CD22 expression, and a 22-fold and 25.7-fold increase in InO LC50 for Nalm6 and REH, respectively, confirming the direct impact of EBF1 on CD22 transcription and InO sensitivity. Because BCR::ABL1-positive ALL showed the greatest variability in InO sensitivity among all B-ALL subtypes, we further investigate the role of the EBF1/CD22 axis on InO sensitivity within this subtype. Unsupervised clustering of gene expression profiles revealed two distinct groups, namely BCR::ABL1 ALL with multilineage (BCR::ABL1-M) or lymphoid only (BCR::ABL1-L) involvement [PMID: 38153913]. Compared to BCR::ABL1-L, BCR::ABL1-M displayed markedly reduced CD22 expression (P=8.3×10-11) and resistance to InO (P=1.9×10-4), likely due to the lower expression and frequent somatic alteration of EBF1. Finally, we established PDX models for representative cases of BCR::ABL1-M and BCR::ABL1-L. Strikingly, InO treatment did not affect leukemia progression in the BCR::ABL1-M PDX model, whereas the BCR::ABL1-L PDX model achieved complete remission and has remained leukemia free to date. Conclusion: Collectively, these data demonstrate the direct impact of EBF1 on CD22 expression during B-cell development, and explain the heterogeneity of InO sensitivity, even within the same molecular B-ALL subtype.

Background TP53-mutant (mt) myelodysplastic syndromes (MDS) are high-risk (HR) neoplasms, with high rates of AML progression and suboptimal response to hypomethylating agents (HMA). Given the lack of effective therapies for HR-MDS, azacitidine (AZA) was combined with venetoclax (VEN) in a phase Ib MDS study demonstrating safety and early efficacy (Garcia et al. ASH abstract 2023). We retrospectively sought to explore clinical outcomes comparing VEN + HMA, to HMA alone in TP53mt HR-MDS. Methods Among 221 TP53mt MDS pts treated at the Mayo Clinic between January 2007 and April 2024, we reviewed outcomes of pts who received HMA alone (n=98) or HMA+VEN combination (n=34) as their first-line chemotherapy regimen. MDS diagnosis was based on the 5th edition of WHO classification of hematolymphoid tumors (Khoury et al. Leukemia 2022). Responses were assessed according to the International Working Group 2006, MDS response criteria (Cheson et al Blood 2006). Results Baseline characteristics and response The median age (years [yrs]) was 65 (R,37-80) and 70 (range [R], 19-87) yrs in the HMA + VEN and HMA alone groups (gps) (p= 0.42), respectively. The median bone marrow (BM) blast % (9.5 [R, 0-18] vs 5 [R, 0-16], p= 0.01) and TP53 variant allele frequency (VAF) (42 [R, 6-96] vs 37 [R, 2-94], p= 0.03) were significantly higher in HMA + VEN compared to HMA gps, respectively. However, proportion of pts with biallelic (BA)/multihitTP53mt (85% vs 79%, p= 0.61) and complex cytogenetics (CG) (85% vs 81%, p= 0.85) were not different between HMA + VEN and HMA alone gps. The distribution of pts with frequently occurring myeloid co-mutations (ASXL1, TET2, DNMT3A, RAS, BCOR and splicing factor) were not significantly (NS) different between the two gps. IPSS-M scores were assessed in 108 (83%) pts; HR/very HR-MDS as per IPSS-M were NS different between HMA + VEN and HMA gps (100% vs 91%, p= 0.12). While the overall response rate (ORR) (76% vs 49%, p= 0.01) and marrow complete remission (mCR) rates (21% vs 7%, p= 0.05) were higher with HMA+VEN compared to HMA, CR rates were similar (17% vs 12%, p= 0.47). Higher proportion of pts were bridged to allogeneic stem cell transplantation (allo-HCT) (41% vs 20%, p= 0.02), while AML progression rates (29% vs 31%, p= >0.99) were comparable between HMA + VEN and HMA gps, respectively. The non-relapse mortality (NRM) at day 60 (3% vs 3%, p=0.96) and day 90 (3% vs 4%, p=0.75) were comparable between HMA + VEN and HMA gps, respectively. RFS and OS The median follow-up from the time of initiation of HMA or HMA + VEN was 9.7 months (mo) (R, 0.3-90.6). The median RFS (8.47 vs 9.90 mo, p= 0.83) and OS (16.33 vs 14.20 mo, p= 0.66) from the time of initiation of therapy were comparable between the two gps. Similarly, among transplanted pts, there was no OS difference between HMA (21.7 mo) and HMA + VEN (18.43 mo) gps, respectively (p= 0.72). Comparable results for OS and RFS were obtained in both gps after censoring pts at the time of allo-HCT. Multivariable analysis for RFS and OS We conducted multivariable analysis (MVA) for RFS and OS using baseline variables that were significant/ trended towards significance (p<0.1), on univariate analysis (UVA) censored at the time of allo-HCT. Achieving ORR (HR; 0.30, 95% CI: 0.14-0.62, p= 0.001) retained significance for better RFS in MVA. Interestingly CR (HR; 1.74, 95% CI; 0.63-4.77, p= 0.28), BA TP53mt (HR; 1.27, 95% CI; 0.13-11.72, p= 0.83) and complex CG (HR; 1.52, 95% CI 0.16-14.03, p= 0.70) did not retain significance for RFS in MVA. In MVA for OS, achievement of ORR (HR; 0.56, 95% CI; 0.30-1.05, p=0.07) and CR (HR; 0.32, 95% CI; 0.09-1.11, p=0.071) trended towards favorable OS. BA TP53mt status (p= 0.42) and complex CG (p= 0.19) did not significantly impact OS in UVA. Conclusion We conclude that while HMA+VEN combination therapy in comparison to HMA monotherapy led to improved response rates, with higher percentage of pts being bridged to allo-HCT, this was not associated with reduced risk of AML transformation, or improved RFS/OS. We eagerly await results from the prospective randomized trial of VEN + AZA in treatment-naïve HR-MDS (VERONA).

Background: While myeloproliferative neoplasms (MPN), including essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (MF), are usually sporadic, adult-onset neoplasms, an increasing number of germline risk alleles have been described (e.g. EGLN1, ETV6, SH2B3, and ATM) in these disorders. DDX41MT Germline Predisposition Syndrome (GPS) is the most common myeloid GPS in adults and while there is extensive data on MDS/AML, little is known regarding MPN occurring in this context. We carried out this study to define the prevalence and characteristics of DDX41MT-GPS associated MPN. Methods: After IRB approval, we retrospectively assessed the Mayo Clinic cohort of 174 patients with DDX41MT-GPS, which included both pathogenic and clinically relevant germline variants of undetermined significance (VUS), based on our previous analysis (Badar et al Haematologica 2023). Standard statistical measures were applied. Results: We identified 12 (6.9%) patients with MPN (ET-5, PV-2, PMF-4, MPN-NOS-1). The median age at MPN diagnosis was 61.2 years (range, 8.-70.4); 58.3% (n=7) were male, and 83.3% (n=10) were Caucasian. A family history of hematologic malignancy was present in 16.7% (n=2, AML and T-LGL), while 50% (n=6) had a family history of visceral malignancies and 41.7% (n=5) had no family history of malignancies. Among ET patients (n=5) with DDX41MT-GPS, JAK2V617F was the MPN driver in 4 (80%) while type 1-CALR (L367fs*46) was a driver in 1 (20%). This included a 9-year-old child diagnosed with JAK2V617FMT ET. The DDX41 variant was classified as pathogenic in 40% (n=2; E113Kfs*14, D140Gfs*2) and VUS in 60% (n=3; V544L, V591I, P38L). Bone marrow (BM) aspirates in the ET patients were hypercellular in 40% (n=2), normocellular in 40% (n=2) and hypocellular in 20% (n=1), and none had increased blasts, or reticulin fibrosis (RF). In addition to JAK2V617F, somatic mutations seen included SF3B1 (K666T, VAF 16%) in 1 patient and IDH2 (R140Q, VAF 6%) and DNMT3A (R882H, VAF 7%) in 1 patient, respectively. With a median follow-up from diagnosis of 3.9yrs (range 2.9-8.9), there were no thrombotic events and no disease progressions was documented. There were 2 patients with JAK2V167FMT PV in whom the DDX41MT were clinically significant VUS (c.138+5G>T and M155I). Both patients had hypercellular BM, with no increase in blasts, no RF, normal karyotypes and no additional somatic mutations. With a median follow up of 7.5yrs (range, 2.1-12.9), 1 patient developed a deep vein thrombosis (DVT) and there were no fibrotic or leukemic transformations. There were 4 patients with PMF; 3 (75%) with JAK2V617F and 1(25%) with a type 1-CALR driver mutation (L367fs*46). DIPPS-plus scores ranged from 1 to 4 (median 2.5). The DDX41 variants were pathogenic in 50% (n=2, E256K and P78Qfs*3) and VUS in 50% (n=2, P510S and M155I). The median grade of RF at PMF diagnosis was grade 2 (range, 2-3). BM were hypercellular in 75% (n=3) and hypocellular in 25% (n=1), and 1 patient had 3% peripheral blasts (and no BM blasts). Somatic co-mutations included TET2 in 1 patient with a JAK2V617F, and CBL, EZH2 and SRSF2 in 1 patient with a CALR driver-mutation, respectively. PMF patients were treated with ruxolitinib (n=3), stem cell transplant (n=1), and pIFNα (n=1). With a median follow up of 3.9yrs (range,1.1-21.9), all patients were alive, and none had leukemia transformation. There was 1 patient with a JAK2V617F MPN-NOS with trisomy 9, where the DDX41MT-GPS was a VUS (I215L). There were no somatic co-mutations and at last follow up (3.1 years), there was no evidence for progression. Conclusions: While associations between late onset MDS/AML and DDX41MT-GPS has been well established, we systematically describe the MPN landscape seen in this context. MPN was diagnosed in 7% of our cohort, with JAK2V617F being the most common driver mutation. Most importantly, unlike in AML/MDS, where somatic DDX41 mutations are frequently associated with neoplastic transformation (30-50%; R525H being most common), none of our MPN patients had a somatic DDX41 mutation. Our work underscores the importance of germline mutation testing in patients with MPN.