Saliba, Antoine N.

Abstract Background: TP53-mutated myeloid neoplasms (MNs) represent one of the most lethal subgroups of blood cancers. The World Health Organization (WHO-5) recognize TP53-mutated (TP53mut) myelodysplastic syndrome (MDS) and International Consensus Classification (ICC) recognize TP53mut MDS and acute myeloid leukaemia (AML) as distinct disease entities, acknowledging their dismal prognosis and the urgent need for novel therapeutic strategies. However, key discrepancies exist between the classifications, creating uncertainty in diagnosis, influencing therapeutic decisions, and complicating clinical trial enrolment for patients with uniformly poor survival. Importantly, neither classifications included TP53-mutated myelofibrosis (MF), other myeloproliferative neoplasms (MPN), and MDS/MPN overlap syndromes, despite growing evidence that these cases carry similar adverse outcomes. To address these critical gaps, we conducted a comprehensive analysis across the full spectrum of TP53-mutated MN. Methods: We included TP53mut cases with variant allele frequency (VAF ≥2%) of AML, MDS, MDS/MPN overlap, myelofibrosis and other MPN managed at the Mayo clinic (Rochester, USA) and Local Health Network in South Australia (Australia). Cases were classified according to the revised 4th edition WHO classification (WHO-4R). Biallelic TP53 loss was defined as: (i) ≥2 mutations with VAF ≥2%; (ii) single TP53mut with VAF ≥2% plus 17p loss on karyotype, FISH, or SNP array; or (iii) single TP53mut with VAF ≥50% with or without 17p loss. Monoallelic loss was defined as a single TP53mut with VAF <50% without 17p loss or copy neutral loss of heterozygosity. The primary endpoint was overall survival (OS) from diagnosis, censored at allogeneic transplantation. Conditional inference tree analysis was performed to define the effect of individual predictors on OS. Results: We identified 853 TP53mutMN cases including WHO-4R-defined AML (BM/PB blasts ≥20%, n=314; 36.8%), MDS with excess blasts-2 (EB-2; BM 10–19% or PB 5–19%, n=129; 15.1%), MDS-EB-1 (BM 5–9% or PB 2–4%, n=100; 11.7%), and MDS with low blasts (LB; BM <5% and PB <1%, n=228; 26.7%). MF included chronic phase (MF-CP, n=48; 5.6%), accelerated phase (MF-AP, n=7; 0.8%), and blast phase (MF-BP, n=17; 2.0%). Additional cases comprised other MPN-chronic phase (n=3, 0.4%) and MDS/MPN overlap syndromes (n=7, 0.8%). Of 848 evaluable TP53mut MN, 616 (72.6%) harbored biallelic TP53 loss and 232 (27.4%) had monoallelic loss, with 42.4% (n=98) of monoallelic cases harboring a complex karyotype (CK). Biallelic loss was highly prevalent in AML (83.1%), MDS (70.4%), and MDS/MPN overlap (71.4%), but was less frequent in cases with MPN (33.3%) and MF-chronic phase (25.0%). Across the spectrum, the frequency of biallelic loss increased stepwise with disease progression, rising from MDS-LB (62.8%) to MDS-EB1 (76.0%), MDS-EB2 (79.5%), AML (83.1%), and MF-AP/BP (79.2%) (P<0.0001). In multivariable analysis, WHO-4R category, TP53mut VAF, biallelic loss and CK were independent predictors of poor survival in TP53mut MN. Conditional inference tree analysis stratified the cohort into seven prognostic groups with distinct median OS: (1) AML, MF-BP/AP, and MDS/MPN overlap regardless of mono/biallelic and CK status (n=335, 39.7%; median OS 4.0 months); (2) MDS-EB1/EB2 with biallelic loss or monoallelic plus CK (n=212, 25.1%; 7.2 months); (3) MDS-LB, MF-CP and MPN with CK (n=156, 18.5%, OS 10.2 months); (4) biallelic MDS-LB (n=28, 3.3%; OS 15.6 months), (5) monoallelic MDS-EB1/EB2 without CK (n=20, 2.4%; OS 26.2 months), (6) monoallelic MDS-LB without CK (n=57, 6.7%; OS 33.4 months), and (7) MF-CP and other MPN without CK (n=36, 4.3%; OS 37.0 months). This analysis defines a clear stepwise risk gradient, identifying subsets with extremely poor prognosis versus a relatively indolent disease. Conclusions: This is the first study to evaluate the prognostic impact of TP53mut MN across the entire MN spectrum, providing a framework for future refinement of TP53-driven disease classification. Key findings include: (i) MF-AP/BP and MDS/MPN overlap exhibit survival outcomes as dismal as AML, irrespective of the TP53 allele status; and (ii) complex karyotype is a surrogate for “biallelic equivalent”, refining risk interpretation in monoallelic cases. Overall, our study defines seven prognostic subgroups spanning all TP53mut MN, offering a foundation for risk-adapted clinical trial design and future classification updates.

Abstract Introduction The European Leukemia Net (ELN) 2022 stratified acute myeloid leukemia (AML) patients (pts) treated with intensive chemotherapy (IC) into three groups based on genetic features. ELN 2024 (Döhner et al, Blood) and Beat AML 2024 (Hoff et al, Blood Advances) proposed revised systems to better capture the impact of genetic features in pts receiving less-intensive therapy (LIT). Real-world validation across treatment settings, including allogeneic hematopoietic stem cell transplantation (allo-HCT), is warranted. Methods We evaluated the performance of ELN 2022, ELN 2024, and Beat AML 2024 among AML pts treated at Mayo Clinic from 2016 to 2025. Only treated pts with available molecular data included. Response was assessed according to the ELN 2022 criteria. Overall survival (OS) was calculated from diagnosis. Multivariable Cox proportional hazard (CPH) models were used to adjust for covariates. Model performances were assessed using Harrell's c-index. Results 426 AML pts (median age 68 years; 60% male) were included; 195 (46%) received IC and 231 (54%) received LIT, while Allo-HCT was performed in 133 (31%) pts. Complex karyotype was present in 126 (30%) and normal cytogenetics in 143 (34%) pts. Molecular mutations included TP53 (20%), TET2 (18%), DNMT3A (16%), SRSF2 (16%), RUNX1 (16%), ASXL1 (16%), and NPM1 (15%). Among evaluable pts (83%), complete remission (CR) after first-line therapy was achieved in 47%. Risk group assignments varied: ELN 2022 vs. ELN 2024 classified pts as favorable (20% vs. 55%), intermediate (20% vs. 24%), and adverse (60% vs. 20%); Beat AML 2024 categorized pts as favorable (41%), intermediate (21%), and adverse (38%). ELN 2024 reclassified 229 (54%) pts of whom 5% upstaged and 49% downstaged, primarily affecting ELN 2022 adverse (67%) and intermediate (46%) groups. Among LIT-treated, CR rates did not differ across groups in any classification. Per ELN 2024, CR was achieved in 43% (favorable), 67% (intermediate), and 29% (adverse) of the LIT-treated pts. However, among IC-treated pts, CR was higher in favorable/intermediate vs. adverse groups across all models (p<0.0001). Allo-HCT was most common in ELN 2024 intermediate (41%) and favorable (32%) vs. adverse (16%) groups. Median OS (months; 95% CI) for the entire cohort was 15.7 (12.5–20.9) with median follow-up time of 49.8 (40.9-55). By ELN 2022, OS of the entire cohort was 49.4 (30.7–NA) for favorable, 50.0 (29.2–NA) for intermediate, and 8.8 (7.7–11.2) for adverse (p<0.0001). Per ELN 2024, OS of the entire cohort was 25.4 (18.5–37.3), 20.3 (13.4–39.8), and 5.7 (3.4–8.2), respectively (p<0.0001). Beat AML 2024 stratified OS of the entire cohort as 42.5 (30.7–NA), 11.4 (9.3–16.7), and 5.6 (3.5–8.0) for favorable, intermediate, and adverse groups (p<0.0001). ELN 2024 stratified the OS of the pts treated with LIT as 15.7 (10.1-24.9), 8.0 (4.9-13.9), and 6.8 (3.4-10.2) for favorable, intermediate and adverse risk groups, (p <0.0001). Among ELN 2022 adverse-risk pts, those reclassified as favorable per ELN 2024 had superior OS (15.0, 9.8–22.7) compared to intermediate (7.8, 5.0–9.3) or adverse (5.4, 3.3–8.0) risk groups, p<0.0001. C-index (95% CI) for OS in the entire cohort was highest for Beat AML 2024 (0.658, 0.629–0.688), followed by ELN 2022 (0.627, 0.599–0.655), and ELN 2024 (0.600, 0.568–0.631). In LIT-treated pts, ELN 2024 (0.597, 0.558–0.637) and Beat AML 2024 (0.586, 0.545–0.627) outperformed ELN 2022 (0.559, 0.521–0.596). Among allo-HCT pts, regardless of treatment type, ELN 2022 (0.610, 0.539–0.681) performed better than ELN 2024 (0.568, 0.487–0.648). In multivariable CPH models adjusted for age, bone marrow blasts, treatment intensity, and complex karyotype, ELN 2022 and ELN 2024 adverse-risk groups had higher hazard of death (HR 2.4, 1.6–3.5 and HR 1.7, 1.1–2.5, respectively, vs. favorable). No significant difference was observed between intermediate and favorable risk for ELN 2022 (HR 1.4, 0.9–2.2) or ELN 2024 (HR 1.4, 0.9–1.9). Allo-HCT was associated with a lower hazard of death (HR 0.4, 0.3–0.5). Conclusions In this real-world AML cohort, ELN 2024 and Beat AML 2024 improved OS prediction in LIT-treated pts compared to ELN 2022. This advantage was not observed in allo-HCT pts. Multivariable analysis confirmed the adverse-risk group as having the worst prognosis across all models. These findings highlight the importance of aligning molecular risk stratification with treatment modalities to enhance prognostication in AML.

Abstract Background Missense mutations in IDH1 are well-established therapeutic targets in acute myeloid leukemia (AML). In contrast, the synonymous IDH1 variant p.Gly105Gly (rs11554137), present in 5–10% of AML cases, has been considered a benign polymorphism due to its high population frequency (5.7% overall, 0.7–10.5%) and lack of protein-altering effect. However, prior studies have associated this variant with inferior outcomes (Wagner, J Clin Oncol, 2010), though findings have been inconsistent. Few studies have examined its prognostic significance in the context of treatment intensity or allogeneic stem cell transplantation (SCT). Methods With IRB approval, clinical and genomic data were extracted from the Mayo Clinic AML database for patients diagnosed between Jan 1, 2018, and Jan 31, 2025. Patients were stratified by IDH1 Gly105Gly (rs11554137) status via NGS on bone marrow. Outcomes included co-mutation profiles, treatment response, measurable residual disease (MRD) by multiparametric flow cytometry, and survival. Multivariable Cox and logistic regression models for relapse-free survival (RFS) and overall survival (OS) were adjusted for age at diagnosis, ELN 2022 risk category, and SCT conditioning regimen. Results Among 379 AML patients, 36 (9.5%) harbored the IDH1 Gly105Gly (rs11554137) variant (cases) (median VAF 49%, IQR 48–49.2). In the full cohort, median age was 68 years (IQR 59–74), M:F ratio was 1.5; 75% had de novo AML, and median follow-up was 52 months. Among cases, common cytogenetic abnormalities included complex karyotype (28%), del(7q) (14%), and trisomy 8 (6%), while frequently mutated genes included DNMT3A (19%), IDH2 (17%), and BCOR (14%). Of 345 treated patients, 43% received intensive, and 56% received low-intensity regimens, including hypomethylating agent (HMA) alone (n=13), HMA+venetoclax (n=159), and targeted therapy (n=7). Among cases, complete remission (CR) rates were higher with intensive vs. low-intensity therapy (70% vs. 17%, p=0.03). MRD positivity post induction was more common in cases (66% vs. 26%, p=0.01), suggesting suboptimal leukemic clearance. Among 103 patients who underwent allogeneic SCT in CR1 (47% received myeloablative conditioning), morphologic relapse occurred in 64.3% of cases compared to 23.6% of controls (p = 0.004). Cases experienced significantly inferior median RFS (8 months [95% CI 5–NA] vs. not reached for controls, p <0.001), indicating more durable post-SCT remission in the control group. In a multivariable Cox proportional hazards model adjusting for age, ELN risk, conditioning intensity, MRD status, and complex karyotype, the IDH1 Gly105Gly variant remained independently associated with shorter RFS (HR 3.97, 95% CI: 1.74–9.05, p = 0.001). Complex karyotype was also an independent predictor of relapse (HR 3.35, 95% CI: 1.28–8.73, p = 0.014). Consistent with this, logistic regression revealed a significantly increased odds of post-SCT relapse among cases (OR 7.95, 95% CI: 2.19–35.27, p=0.001), independent of clinical covariates. Relapsed cases were significantly more likely to harbor FLT3-ITD mutations than relapsed controls (p=0.041). Pathway-level analysis revealed increased frequency of mutations in signal transduction genes (FLT3-ITD, CSF3R, NF1) (p=0.002). All CNS relapses among cases occurred in patients harboring at least one of these mutations. Despite the higher relapse rate, there were no significant differences in OS (14.4 vs. 11.3 months, p=0.36) between cases and controls. The IDH1 Gly105Gly variant was not independently associated with OS (HR 1.26, p=0.30). In contrast, age (p<0.0001) and adverse ELN risk (p<0.0001) were significant predictors of inferior OS. These findings suggest that the prognostic impact of IDH1 Gly105Gly is most pronounced in the post-SCT setting. Conclusion The synonymous IDH1 Gly105Gly variant (rs11554137) is an independent predictor of post-SCT relapse in AML, potentially mediated by co-occurring mutations in signal transduction pathways. Despite no observed impact on OS, likely due to effective salvage therapies, the variant's link to lower CR rates with low-intensity therapy and higher MRD burden suggests treatment intensity influences its clinical relevance. These findings support reevaluating the prognostic role of synonymous variants in AML and call for larger studies and mechanistic investigations into splicing, transcript stability, and translation.

Abstract BACKGROUND: DNA methyltransferase inhibition offers palliative benefit but does not alter disease biology. in chronic myelomonocytic leukemia (CMML, Merlevede J et al. Nat Comm 2016). This was conclusively demonstrated in the phase 3 DACOTA study, where decitabine did not improve event-free survival in comparison to hydroxyurea (median 12.1 versus 10.3 months, P=0.27) in advanced myeloproliferative CMML (MP-CMML). Hence, there is in urgent need to develop disease modifying therapies for this dismal condition. We and others have demonstrated a role for RAS mutations in MP-CMML through the activation of the KMT2A-PLK1 axis. Targeting of this axis using onvansertib, an inhibitor of PLK1, has demonstrated its pre-clinical efficacy in MP-CMML patient-derived organoid and xenograft models. (Carr RM et al. Nat Comm 2021). METHODS: We conducted a single center phase 1 study to assess the safety and efficacy of onvansertib in relapsed/refractory MP-CMML (NCT05549661). We used a Bayesian Optimal Interval (BOIN) study design to determine the maximum tolerated dose (MTD). The three dose cohorts included 6, 9 and 12 mg/m2 given orally from days 1 to 21 of each 28-day cycle. Key inclusion criteria included a WHO-defined diagnosis of MP-CMML with a white blood cell (WBC) count > 13,000/mm3 and adequate organ function (estimated GFR > 50 mL/min/m2). Response was evaluated per the MDS/MPN International Working Group Criteria (Savona et al. Blood 2015). Targeting efficacy was assessed by measuring phosphorylation of TCTP (a PLK1 substrate), specifically pTCTP/TCTP ratios by immunoblotting in peripheral blood mononuclear cell (PBMC) samples pre and post cycle 1 (Days 1, 7, 21) and end of cycle 3. Pharmacokinetic studies and translational correlative studies were conducted per protocol. RESULTS: Between April 2023 and July 2025, a total of 9 patients were enrolled. The median age at enrollment was 68 years (range: 60-83); all caucasian with 4 (44%) males. All patients had a diagnosis of CMML-1 with a median bone marrow (BM) blast percentage of 4 (0-9), median hemoglobin 10 (7.1-13.2) g/dL, median WBC count of 11.1 (3.1-72.7) x 109/L (4 patients had a WBC count < 13 x 109/L at enrollment due to hydroxyurea use but were confirmed to be MP-CMML at diagnosis), absolute monocyte count 2.1 (1.9-19.6) x 109/L, and platelet count of 36 (20-494) x 109/L. TET2 (89%), SRSF2 (78%), ASXL1 (56%), NRAS, KRAS and CBL (22% each) were the most frequent molecular abnormalities. Previous therapies included hydroxyurea (n=8) and decitabine (n=1). Four patients were enrolled at the 6mg/m2dose level, 2 at the 9 mg/m2 dose level and we currently have one patient at the 12 mg/m2 dose level. While there were 2 planned patients at the 6 mg/m2 dose level, due to a case of pericardial effusion that was possibly drug related, an additional two patients were enrolled at the same dose level, without any dose limiting toxicity (DLT). Targeting efficacy was confirmed by pTCTP immunoblotting in PBMC samples from 4 patients (6 and 9 mg/m2 dose levels) showing suppressed pTCTP/TCTP ratios. No confirmed DLT has been identified thus far, and no grade 3 or 4 toxicities attributable to the study drug have been reported. Possible or unrelated grade 3 adverse effects included infections (sepsis/cellulitis, n=2, 22%), acute kidney injury (n=1, 11%), pericardial effusion (n=1, 11%), and atrial fibrillation with rapid ventricular response (n=1, 11%). Median duration on therapy was 124 (range: 15-654) days with most common cause of study discontinuation being disease progression (33%). Response was assessed as per the MDS/MPN IWG criteria in patients who received at least 1 cycle (n=8) with 3 (38%) patients meeting criteria for either hematological or optimal marrow response. Specifically, there was one (14%) patient with >100% platelet response, one (14%) with normalization of WBC count (baseline WBC count >50 x 109/L), one (14%) optimal marrow response with BM blast% reduction from 8 to 2, facilitating candidacy for an allogeneic hematopoietic stem cell transplantation, and three patients (38%) remained as stable disease. CONCLUSION: In MP-CMML, PLK1 inhibition with onvansertib is relatively well tolerated and shows preliminary efficacy in approximately 40% of patients, with one patient having an optimal marrow response at the 9 mg/m2 dose. Future directions include a dose expansion phase and studying upfront combination with DNA methyltransferase inhibitors.

Abstract Introduction: The DEAD-box helicase 41 (DDX41) gene, located on chromosome 5q35, is a tumor suppressor gene involved in RNA processing. Germline mutations in this gene can predispose patients to myeloid malignancies. Studies have suggested a more favorable prognosis in those with germline mutations in DDX41, with progression of disease being a frequently encountered cause of death. In this retrospective study, we explored the causes of death in a cohort of patients with pathogenic DDX41 mutations. Methods: This was a retrospective study of patients diagnosed with myeloid neoplasms between 2009-2024 and found to have DDX41 mutation (DDX41m) via next generation sequencing (NGS) at our institution. Myeloid NGS was obtained at or after the diagnosis of myeloid disease. Germline testing (when available) was performed through buccal/skin samples. Carriers of DDX41m without a myeloid neoplasm diagnosis and patients with only DDX41m VUS were excluded. Baseline characteristics at the time of myeloid neoplasm diagnosis included age at diagnosis, DDX41m variant allele frequency (VAF), blood counts (hemoglobin, white blood cell count, platelets), cytogenetics, bone marrow blast percentage, number of co-mutations, and treatment received. Unadjusted comparisons were made using continuous or categorical variables. Median overall survival (OS) was calculated from the time of diagnosis with myeloid neoplasm to the time of death, using BlueSky Statistics V.10.3.4. Results: Of the 112 patients identified to have pathogenic DDX41m, 29 (26%) patients were deceased at the time of data analysis. In this cohort of 29 patients (median age at diagnosis 72 years, 17 (59%) males), disease groups at initial diagnosis included 17 (59%) patients with MDS, 9 (31%) AML, and 3 (10%) MPN. Fourteen of the 17 (82%) of the patients with MDS were classified as MDS-EB1 or MDS-EB2. Seven of the 17 (41%) patients with MDS progressed to AML at the time of death, with 57% of the patients having more than 30% bone marrow blasts at time of progression. Blood counts at diagnosis in the cohort included a median hemoglobin of 9.8 g/dL, platelets of 83 x 109/L, and white blood cell count of 2.1 x 109/L. Twenty-one (72%) of patients had normal cytogenetics. Nine (31%) patients had both a pathogenic mutation and a variant of uncertain significance (VUS) in DDX41, with the remaining 20 patients harboring only a pathogenic DDX41 mutation. Eight (27%) patients underwent germline testing, with 7 confirmed to harbor a germline DDX41m. In the deceased cohort, 9 (31%) patients underwent HSCT. Three of the patients with AML and 1 patient with MDS were observed and did not undergo treatment. Median overall survival of the deceased cohort was 29 months. The median time to AML progression in the group with MDS was 14 months. Causes of death included infection in 11 (38%) patients, 9 (31%) with disease progression/relapse, 3 (10%) with acute gastrointestinal graft versus host disease (GVHD), and 1 (3%) from cerebral bleed. The cause of death was unknown in the remaining 5 (17.2%) patients. Infections included pneumonia, bacteremia, neutropenic enterocolitis, fungal, and unknown etiology. Of the 4 patients who were observed, 2 died from unknown cause and 2 died from disease progression. Of the 16 patients with AML at time of death, 9 (56%) died from disease progression or relapse, 3 (19%) from infection, 2 (13%) from GVHD, and 2 (13%) from unknown causes. Of the 10 deaths in the MDS group, 7 (70%) were from infection, 1 (10%) from GVHD, 1 (10%) from cerebral bleed, and 1 (10%) from an unknown cause. Three cases of infection in the MDS group occurred during remission. Infection was a more common cause of death in the MDS group compared to the AML group, where disease progression prevailed as a cause of death (70% vs 19%, p=0.01). Eight (80%) of the patients with MDS who died from infection were neutropenic prior to death, and 4 (50%) of those patients were on neutropenic antimicrobial prophylaxis. Conclusions: In this cohort of 29 deceased patients with a DDX41-mutated myeloid neoplasm, we characterized causes of death. Disease progression/relapse was a significantly more common cause of death in those with AML, compared to infection in patients with MDS. Our work underscores the need for additional studies looking into non-leukemic causes of death in patients with DDX41m myeloid diseases and potential strategies to mitigate infection-related mortality in this population.

Abstract Background: KMT2A-rearranged acute myeloid leukemia (KMT2Ar AML) is characterized by chromosomal translocation involving KMT2A gene at 11q23, resulting in fusion with variety of partner genes. It is usually associated with poor outcomes, high risk of relapses and suboptimal responses to conventional therapies. While NPM1-mutated (mt) AML is considered favorable risk, they are equally dismal in relapse refractory (RR) setting. Menin inhibitors have emerged as a promising therapeutic strategy, particularly in RR AML patients (pts) with KMT2Ar and NPM1-mt genotypes. While revumenib, a menin inhibitor approved for managing RR KMT2Ar acute leukemia, no menin inhibitor is currently approved for NPM1-mt AML. In this study, we evaluated clinical outcomes of adults with KMT2Ar AML and performed a comparative analysis of pts with RR KMT2Ar and NPM1-mt AML using data from the Mayo Clinic. Methods: After screening 102 AML pts with reported KMT2A abnormalities, we identified 33 adults with confirmed KMT2Ar diagnosed between 2012 and 2024 for retrospective analysis. Clinical and molecular/cytogenetics data, induction type (intensive chemotherapy [IC] vs non-intensive chemotherapy [NIC]), response, transplant use, and survival outcomes were reviewed. A separate analysis was performed comparing 20 RR KMT2Ar AML pts with 20 propensity score matched RR NPM1-mt AML pts from a pool of 125 NPM1-mt RR pts. Results: The median age was 50 years (yrs) (range [R], 19.0-75.0), and 60.6% were < 60 yrs. Most cases were de novo AML (64%), and the most frequent translocation was t(6;11)(q27;q23)/MLLT4 (27%), followed by t(10;11)(p12;q23)/MLLT10 (21%), t(9;11)(p21.3;q23.3)/MLLT3 (15%), and t(11;19)(q23;p13.1)/ELL (12%). Other KMT2A fusion partners were rare and collectively accounted for the remaining cases. The median follow-up was 57 months (mo) (R, 7.0-109.0). The overall response rate (ORR) was 91%, and composite complete remission (CRc, , including CR, CRi, and CRh) was 73%. The CRc rates were comparable between IC and NIC (80% vs 62%, p=0.24). CRc were not significantly different by disease type (de novo [71.4%] vs secondary [sAML] [75%], p= 0.82) or KMT2A fusion partner gene (60% for t[9;11]/MLLT3 vs. 57.1% for t[10;11]/MLLT10 vs 55.6% for t[6;11]/MLLT4, p=0.069). Seventeen (52%) pts received an allogeneic stem cell transplantation (allo-HCT). The median overall survival (mOS ) for the entire cohort was 16 mo (R, 11.0-34.0). In subset analysis, IC compared to NIC was associated with significantly longer mOS (30 vs 11 mo, p=0.014). The mOS was also superior in pts <60 vs ≥60 yrs (32 vs 8 mo, p=0.005). Similarly, de novo cases had better mOS than sAML (22.0 vs 9.5 mo, p=0.052). Among KMT2Ar subtypes, t(6;11)/MLLT4 showed the longest mOS (54 mo [R, 30.0-not reached (NR)]), while t(9;11)/MLLT3 had the shortest (11.0 mo, [R 9-NR]), but differences were not statistically significant (p=0.32). The mOS was significantly longer among allo-HCT pts (30 vs 11 mo, p=0.005). Among 29 pts who experienced RR disease, the median relapse free survival (RFS) was 3 mo (R, 2.0-10.0). First salvage therapy yielded a CRc of 43.8% in 16 evaluable pts. When compared to a propensity matched cohort of 20 RR NPM1-mt AML pts, the CRc rates was 57.9% vs 50% in RR NPM1-mt and KMT2Ar AML (p= 0.68). The mRFS was not significantly different between RR KMT2Ar and NPM1-mt AML, (3 vs 4 mo, p=0.9). However, KMT2Ar pts had inferior mOS compared to NPM-mt AML (12 vs 65 mo, p=0.004). We further compared survival between NPM1-mt and KMT2Ar pts stratified by allo-HCT status. Among those who underwent allo-HCT, NPM1-mt pts had longer mOS (NR vs 22 mo, p=0.037). Among non-allo-HCT pts, mOS was numerically higher in NPM1-mt vs KMT2Ar (19 vs 8 mo, p=0.11). Conclusions: This single institusion cohort of adult AML with KMT2Ar underscores the biological and clinical heterogeneity of this high-risk group. IC was associated with a survival benefit, particularly among younger and fit patients. However, the outcomes following relapse remained poor, highlighting the urgent need for improved post-remission and salvage therapies. Comparative analysis with matched RR NPM1-mt AML pts revealed similarly dismal survival outcomes. Emerging data from single-arm studies of menin inhibitors in both frontline and RR settings among pts with NPM1-mt and KMT2Ar AML are encouraging and may represent a paradigm shift in treatment.

Abstract Background: Clonal cytopenia of undetermined significance (CCUS) is defined as clonal hematopoiesis in the absence of a hematologic neoplasm, along with unexplained cytopenia. While several studies have identified risk factors and developed scores to predict progression to overt myeloid neoplasms, the clinical and molecular features during the progression process remain poorly understood. Aim: Evaluate the clinical and clonal characteristics of patients with CCUS, with a focus on the longitudinal evolution of clonal and clinical parameters over time. Methods: After IRB approval, we retrospectively reviewed charts of patients with unexplained cytopenia (2015-2024), recording data at the time of CCUS diagnosis (WHO 2022 diagnostic criteria) and at time of follow-up bone marrow biopsy after diagnosis. Follow-up CBC and karyotype data were recorded for patients who had repeat bone marrow biopsies (n= 111), while follow-up clonal parameters and risk scores were calculated for those who underwent repeat NGS (n= 74). A reduction or expansion in clone size was defined as a change exceeding 5% (CE5%), or change exceeding 10% (CE10%) from the baseline value. Overall survival (OS) was calculated from diagnosis to last follow-up. For statistical analysis, we used BlueSky Statistics V10.3.1. Results: 214 CCUS patients (median age 73, 68% males) were included. At baseline, 30% of patients had abnormal cytogenetics, with del (20q) being the most common one (8%; n= 18), followed by trisomy 8 (6%; n= 13), and loss of chromosome Y (5%; n= 10). The median number of mutations was 2 (range, 1-5), with the most common mutations TET2 (38%), SRSF2 (21.5%), ASXL1 (21%), ZRSR2 (18.5%), DNMT3A (9.5%), and U2AF1 (9%). Most patients had high risk CHRS (60%), followed by intermediate (30%), and low risk (10%). On the other hand, 41% had high risk CCRS, 29% had intermediate risk, and 30% had low risk. After a median follow-up of 46 months, 62 patients died (median OS not reached). A decrease in the white blood cell (WBC) count from the time of diagnosis to follow-up was more frequently seen among CCUS patients who progressed to MN (70% vs 50%, p= 0.04), however, changes in hemoglobin and platelets did not differ between those who progressed and those who did not (p> 0.05). Although the frequency of abnormal karyotypes at diagnosis was similar between patients who eventually progressed (28%) and those who did not (31%) (p= 0.6), 4 (2%) patients with initially normal karyotypes acquired chromosomal abnormalities during follow-up, and all progressed to MDS. Among the 74 patients who had follow-up NGS, 31% acquired new mutations, clonal expansion of pre-existing mutations were seen in 54% using CE5% and 19% per CE10%, and 16% developed new variants of uncertain significance (VUS). Acquiring new pathogenic mutations was similar in patients who progressed to MN compared to those who did not progress (34% vs 28%, p= 0.6). On the other hand, clonal expansion was significantly more observed in patients who progressed compared to those who did not, using both CE5% (73% vs 31%, p = <0.001) and CE10% (27% vs 9%, p= 0.03). At follow-up, ASXL1 was the most commonly acquired mutation among patients who did not progress (4 cases), followed by TET2 (2 cases), and U2AF1, GATA2, DNMT3A, SF3B1, ZRSR2, TP53, and CBL (1 case each). On the other hand, SRSF2, SETBP1, CBL, JAK2, TET2, and RUNX1 were more frequently acquired among those who progressed to myeloid neoplasms (each appeared in 2 patients). When recalculating CCRS, CHRS, IPSS-M, and IPSS-R at follow-up for patients who had repeat NGS, there was no significant difference in score changes - either upward or downward - between those who progressed and those who did not (p> 0.05). Conclusion: In CCUS patients who progressed to myeloid neoplasms, WBC decline, clonal expansion (more frequent), and evolving chromosomal aberrations (less frequent) were observed, supporting the value of longitudinal genomic and clinical monitoring in CCUS.

Abstract Background: TP53-mutated (TP53mut) myeloid neoplasms (MN) are a biologically and clinically distinct subgroup of blood cancers associated with extremely poor outcomes and limited response to conventional therapies. In some patients, MN are preceded by clonal cytopenia of undetermined significance (CCUS). Prior cytotoxic exposure (treatment related, TR) is an independent predictor for survival in CCUS (Li et al, Blood Adv. 2024). As TP53mut CCUS and MN are enriched in TR cases, the interaction between cytotoxic exposure and TP53mut status on the risk of progression and survival remains unclear. Methods: Adult patients with CCUS who were evaluated at the Mayo Clinic or South Australian myelodysplastic syndrome (MDS) Registry (Adelaide, Australia) were included. CCUS and MDS were defined according to the 5th edition of the WHO classification for MN (Khoury et al, 2022), except for the exclusion of cases harboring MDS-defining cytogenetics. Next-generation sequencing was performed using a targeted panel covering genes commonly mutated in MN. In cases with >1 TP53mut, VAFs were summed. Survival outcomes were assessed by Kaplan-Meier with log-rank testing. Univariate and multivariate analyses were estimated using Cox proportional hazards regression. Results: Of 320 CCUS cases, 50 (15.6%) harbored TP53mut (TP53mut CCUS), whereas 270 (84.4%) were wild-type (TP53wt CCUS). Median age at diagnosis was 71 years (range 16-99). TP53mut CCUS had a greater proportion of females (60% vs 33.7%, p<0.001) and TR (66% vs 23%, p<0.001) compared to TP53wt. Hematologic parameters including hemoglobin, red cell distribution width, mean corpuscular volume, white blood count, absolute neutrophil count, platelets, and bone marrow blasts were comparable between the two groups. Almost all TP53mut (n=48, 96%) were located in the DNA-binding domain and the median variant allele frequency (VAF) was 9% (range 2-46%). Five (10%) cases harbored 2 TP53mut. The distribution of TP53mut VAF among patients was as follows: ≤2.5% (n=2), 2.5-5% (n=10), 5-10% (n=19), 10-20% (n=11), and ≥20% (n=7). The proportion of cases with cytogenetic abnormalities was smaller in TP53mut compared to TP53wt CCUS(12% vs 25.9%, p=0.035). Both cohorts had a comparable median number of mutations: 2 (range 0-7) in TP53mut and 2 (range 0-5) in TP53wt. The most common co-mutations in TP53mut CCUS were TET2 (n=8, 17.8%), PPMD1 (n=7, 15.6%), DNMT3A (n=6, 13.3%), ASXL1 (n=6, 13.3%), and SRSF2 (n=4, 8.9%). At last follow up, the rate of progression was comparable between TP53mut and TP53wt CCUS (12% vs 22%, p=0.13). Median time to MN progression was not reached in TP53mut and 6.25 months in TP53wt CCUS (p=0.5197). A significantly higher proportion of TP53mut cases acquired complex cytogenetics compared to TP53wt cases (33% vs 2%, p=0.024) at MN progression. Of 20 deaths observed in the TP53mut cohort, non-myeloid hematologic malignancies (n=6, 30%), infections (n=5, 25%), and TP53mut MN (n=4, 20%) were the 3 most common causes. With a median follow-up of 4 years (IQR 1.2-4.8), median OS was longer in de novo (dn) cases (8.7 years for dn TP53wt; not reached for dn TP53mut) and shorter in TR cases (3.3 years for TR TP53wt; 4.8 years for TR TP53mut). Notably, TP53mut showed no independent prognostic impact in the entire cohort, or when stratified by TR vs dn CCUS. On multivariate analysis that included TP53mut status, factors independently associated with inferior OS included prior therapy (HR 2.21, 95% CI 1.41-3.45, p<0.001), anemia (HR 4.1, 95% CI 1.88-8.99, p<0.001), and thrombocytopenia (HR 2.38, 95% CI 1.43-3.95, p<0.001). Similarly, TR CCUS (HR 1.6, 95% CI 1.06-2.4, p=0.03) and anemia (HR 2.15, 95% CI 1.25-3.7, p=0.006) were independently associated with inferior progression free survival. Conclusion: TP53 mut in CCUS did not independently predict inferior survival or increase leukemic transformation. While TP53mut CCUS were less likely to harbor cytogenetic abnormalities at diagnosis, significantly more cases harbored genomic instability at leukemic transformation. The poor outcomes attributed to TP53mut CCUS were driven by prior cytotoxic exposure, cytopenia – particularly anemia, and non-leukemic causes of death. These findings suggest risk stratification in CCUS should prioritize clinical context over TP53mut status alone.

Abstract Background: Isocitrate dehydrogenase (IDH) mutations are frequently implicated in the development of acute myeloid leukemia (AML). In a recent study (Salman MY, Blood Adv 2025), it was reported that IDH2 mutation subtypes, R140 and R172, may respond differently to intensive chemotherapy. In this study, we evaluated mid-cycle and end-of-cycle bone marrow blast responses in AML patients with IDH2 R140, IDH2 R172, and IDH1 R132 mutations, aiming to determine whether these subtypes exhibit different response dynamics. Methods: We reviewed the charts of AML patients diagnosed at Mayo Clinic, Rochester, between the years 2016 - 2023 that had available next generation sequencing (NGS) data. Institutional review board approval was obtained. All data were recorded at the time of AML diagnosis. Patients without molecular data or not treated with intensive chemotherapy (7+3 or CPX-351) were excluded from this study. Bone marrow blast percentages were assessed at mid-induction (days 14-21) and end of cycle (counts recovery). Blast clearance dynamics and complete remission rates were compared across IDH mutation subgroups and correlated with outcomes. GraphPad Prism 10.0.0 was used for statistical analysis. Results: Out of 381 AML patients, 31 had IDH2 mutations (23 with R140 and 8 with R172), and 8 had IDH1 mutations (all R132). Among patients with IDH2 mutations, those with R172 had numerically higher median mid-cycle bone marrow blast percentage compared to R140 (10% vs. 4%, p = 0.37). There was no significant difference in mid-cycle blast percentages between patients with IDH1 and IDH2 mutations (4.5% vs. 4%, p = 0.8). At mid-cycle, 68% of patients with IDH2 R140 had blast counts <5%, compared to 38% of those with IDH2 R172, suggesting a trend for faster mid-cycle clearance in the R140 group, though not statistically significant (OR 3.57, p = 0.2). In a broader comparison, 60% of IDH2-mutated patients and 50% of IDH1-mutated patients achieved blast clearance (blasts <5%) at mid-cycle, though not statistically significant (p = 0.7). At the end of the induction, patients with IDH2 R140 had significantly lower median bone marrow blast percentages compared to those with R172mutations (2% vs. 4%, p = 0.01). Similarly, patients with IDH1 mutations showed low blast counts compared to the IDH2 group (1.5% vs. 3%, p = 0.1). A higher proportion of IDH2 R140 patients achieved blast clearance compared to those with R172 mutations (100% vs. 75%, p = 0.06), while proportion of patients who achieved blast clearance were similar between IDH1 and IDH2 patients (87.5% vs 93.1%, P = 0.5). Analysis of overall complete remission rates (including both complete remission [CR] and CR with incomplete hematologic recovery [CRi]) within the IDH2-mutated group showed a higher rate in patients with the R140 mutation compared to those with R172 (87% vs. 75%), though the difference was not statistically significant (p = 0.5). When comparing IDH1- and IDH2-mutated patients, overall complete remission rates were 75% and 84%, respectively, with no significant difference observed (p = 0.6). Kaplan–Meier analysis of time to end-of-induction blast clearance revealed no statistically significant difference between IDH2 R140 and R172 patients (median time to clearance: 31 vs. 37 days, p = 0.3). Similarly, no difference was observed between IDH1 and IDH2-mutated patients (33 vs. 31 days, p = 0.9). Overall survival analyses showed no significant difference between IDH2 R140 and R172 groups (median 66.8 months vs not reached, P = 0.4). Likewise, no difference was observed between IDH1 and IDH2 patients (44.4 months vs not reached, P = 0.7), indicating similar overall survival across mutation subtypes. Conclusion: IDH2-R140 was associated with more effective blast cytoreduction following intensive induction compared to IDH2-R172. Although not statistically significant, IDH2 R172consistently showed trends toward higher blast percentages, delayed response, and lower overall complete remission rates. These findings align with the recent study reporting significantly slower blast reduction and delayed response in R172-mutated AML. Also, no significant differences were found between IDH1- and IDH2-mutated patients in terms of response kinetics or overall survival. Together, these findings highlight potential biological differences among IDH mutation subtypes that may impact treatment response and require further investigation in larger prospective cohorts.

Abstract Introduction: Leukemogenesis is driven by nucleophosmin 1 mutations(NPM1-m) or lysine methyltransferase 2A rearrangements(KMT2A-r) in ~35–40% of acute myeloid leukemia (AML) cases. Nearly half of AML patients will develop relapsed/refractory (R/R) disease within a year, with <20% expected response rate following venetoclax/azacitidine (Ven/Aza) and progressively poorer outcomes with each subsequent line of therapy. Ziftomenib–a potent, highly selective, oral, investigational menin inhibitor–has demonstrated clinical activity as both monotherapy and in combination for adults with R/R NPM1-m or KMT2A-r AML. KOMET-007 (NCT05735184) is an ongoing, open-label, ph1a/b study of ziftomenib in combination with standard chemotherapies in adults with newly diagnosed and R/R NPM1-m or KMT2A-r AML. Here we present updated safety and clinical activity in patients with R/R AML treated with the recommended ph2 dose (RP2D) of ziftomenib 600 mg in combination with Ven/Aza across ph1a/b. Methods: Adults (≥18y) with R/R NPM1-m or KMT2A-r AML enrolled independently into separate arms; patients in dose escalation (ph1a) and expansion (ph1b) were treated with oral ziftomenib 600 mg once daily (QD; continuously from C1D8 onward) plus standard doses of Ven/Aza. Primary endpoints: AEs, complete remission (CR; ELN 2022), dose limiting toxicities (DLT; ph1a only). Key secondary endpoints: composite CR (CRc; CR with full, partial or incomplete hematologic recovery), overall response, duration of response. Results: As of June 25, 2025, 80 patients (51 NPM1-m, 29 KMT2A-r) with R/R AML were enrolled (20 ph1a; 60 ph1b) and treated with ziftomenib 600 mg QD + Ven/Aza. Median age was 63y (range 19–85), 50% were female, 74% had ECOG PS 0–1; 22 (28%) had FLT3 co-mutations and 7 (9%) had IDH co-mutations. Median number of prior therapies was 1 (range 1–6); 18% (14/80) had prior stem cell transplant; 25 (49%) NPM1-m and 19 (66%) KMT2A-r patients had prior Ven exposure. 71 patients (89%) had Gr ≥3 treatment-emergent AEs, most commonly (≥20% of patients) febrile neutropenia (31%), decreased platelet count (28%), decreased white blood cell count (26%) and decreased neutrophil count (23%). Gr ≥3 ziftomenib-related AEs occurred in 30 patients (38%), most commonly febrile neutropenia (9%) and anemia (8%). 6% of patients discontinued ziftomenib treatment due to AEs. Differentiation syndrome (DS) occurred in 1 (1%) NPM1-m patient (Gr 3), which lasted 1d and successfully resolved with protocol-specified DS mitigation. No ziftomenib-related QTc prolongation was reported with the combination, and no DLTs were observed in ph1a. 70 patients (43 NPM1-m; 27 KMT2A-r) were response-evaluable (≥1 response assessment or death). Median follow-up was 18.0 wks for NPM1-m and 16.4 wks for KMT2A-r. Overall response rates (ORRs) were 65% (28/43) for NPM1-m and 33% (9/27) for KMT2A-r. CRc rates were 49% (21/43) for NPM1-m and 22% (6/27) for KMT2A-r after median time to first CRc of 4.9 wks (range 2.7–15.6) and 5.5 wks (range 2.6–18.9), respectively; measurable residual disease (MRD)-negativity rates (local) among tested CRc responders were 50% (9/18) for NPM1-m and 60% (3/5) for KMT2A-r after median time to first MRD-negativity of 5.9 wks (range 2.9–15.6) and 8.1 wks (range 7.7–18.9), respectively. During continuous ziftomenib administration in patients who achieved CRc, median time to neutrophil recovery (≥1×109/L) was 43d overall (43d for NPM1-m; 71d for KMT2A-r), and median time to platelet recovery (≥100×109/L) was 27d overall (27d for NPM1-m; 23d for KMT2A-r). As of the data cutoff, overall median duration of CRc was not estimable; median overall survival was not estimable for NPM1-m and 21.1 wks for KMT2A-r. In Ven-naive patients, CRc rates were 71% (15/21) for NPM1-m and 33% (3/9) for KMT2A-r; CR rates were 48% (10/21) and 11% (1/9); and ORRs were 81% (17/21) and 56% (5/9), respectively. The study is ongoing with 44% (19/43) of NPM1-m and 11% (3/27) of KMT2A-r patients still on treatment, with responses continuing to evolve.Updated data to be presented.Conclusions: In the ongoing KOMET-007 study, ziftomenib RP2D of 600 mg QD + Ven/Aza was well tolerated with robust clinical activity in patients with R/R NPM1-mor KMT2A-rAML. No ziftomenib-related QTc prolongation was reported. One case of DS (NPM1-m, Gr 3) successfully resolved with protocol-specified mitigation. These data support further investigation of ziftomenib-based combinations in R/R NPM1-mand KMT2A-rAML.