Gangat, Naseema

ABSTRACT The clinical relevance of TP53 mutations ( TP53 MUT ) in myeloproliferative neoplasms (MPN) and their prognostic interaction with MPN subtype designation has not been systematically studied. In the current study, 114 patients with MPN harboring TP53 MUT (VAF ≥ 2%) were evaluated for overall survival (OS), calculated from the time of TP53 MUT detection: chronic phase myelofibrosis (MF‐CP; N = 61); blast‐phase (MPN‐BP; N = 31) or accelerated‐phase (MPN‐AP; N = 16) MPN, and polycythemia vera/essential thrombocythemia (PV/ET; N = 6). Sixty‐five (57%) patients harbored International Consensus Classification (ICC)‐defined multihit TP53 MUT and 56 (49%) monosomal/complex karyotype (MK/CK). Majority of MPN‐BP (90%) and MPN‐AP (81%) while 39% of MF‐CP and none of PV/ET patients harbored multihit TP53 MUT . OS in MPN‐BP and MPN‐AP was equally dismal (median 6 vs. 4.5 months, respectively; p = 1.0), regardless of multihit configuration ( p = 0.44), while OS in TP53 MUT MPN‐BP/AP ( N = 47; median 4 months) was inferior to that of a separate cohort ( N = 49) with TP53 wild‐type MPN‐BP/AP (median 11 months; p < 0.01). OS in MF‐CP was significantly shorter with multihit versus non‐multihit TP53 MUT (median 10 vs. 35 months; HR 2.9; p < 0.01), independent of other MF‐relevant genetic risk factors, including ASXL1/SRSF2/U2AF1 mutations. Multihit TP53 MUT was also associated with inferior survival following allogeneic stem cell transplant (ASCT): median 9 months versus “not reached” in patients with ( N = 9) versus without ( N = 8) multihit TP53 MUT ( p < 0.01). The presence of multihit or non‐multihit TP53 MUT in MPN‐BP/AP or multihit TP53 MUT in MF‐CP is associated with exceptionally poor prognosis and justifies inclusion into the ICC category of “myeloid neoplasms with mutated TP53 .” By contrast, detection of non‐multihit TP53 MUT , by itself, might not endanger short‐term survival in MF‐CP, PV, or ET.

Importance Essential thrombocythemia, a clonal myeloproliferative neoplasm with excessive platelet production, is associated with an increased risk of thrombosis and bleeding. The annual incidence rate of essential thrombocythemia in the US is 1.5/100 000 persons. Observations Patients with essential thrombocythemia have a persistent platelet count of 450 × 10 9 /L or greater. The differential diagnosis includes myeloproliferative neoplasms (polycythemia vera, primary myelofibrosis, chronic myeloid leukemia); inflammatory conditions such as rheumatoid arthritis and systemic lupus erythematosus; infections; splenectomy; iron deficiency anemia; and solid tumors such as lung cancer. Approximately 90% of individuals with essential thrombocythemia have genetic variants that upregulate the JAK-STAT (signal transducer and activator of transcription 5) signaling pathway, including Janus kinase 2 (JAK2, 64%), calreticulin (CALR , 23%), and myeloproliferative leukemia virus oncogene (MPL , 4%). The median age at diagnosis of essential thrombocythemia is 59 years. The median overall survival exceeds 35 years in those diagnosed at 40 years or younger. Patients with essential thrombocythemia are at increased risk of arterial thrombosis (11%), venous thrombosis (7%), and hemorrhagic complications (8%). Thrombosis risk is increased among those with a history of thrombosis, age older than 60 years, a JAK2 gene variant, and cardiovascular risk factors (eg, hypertension, diabetes mellitus, hyperlipidemias, tobacco use). Use of aspirin (81-100 mg/d) is suggested for most patients with essential thrombocythemia to lower thrombosis risk. In a retrospective study of 300 affected patients with a low thrombosis risk (younger than 60 years with no prior thrombosis), those not taking aspirin (100 mg/d) had a risk of arterial thrombosis of 9.4/1000 patient-years and a venous thrombosis risk of 8.2/1000 patient years; cardiovascular risk factors were associated with a higher risk of arterial thrombi (incidence rate ratio, 2.5 [95% CI, 1.02-6.1]), and a JAK2 gene variant was associated with increased risk of venous thrombosis (incidence rate ratio, 4.0 [95% CI, 1.2-12.9]). In a randomized trial of 114 patients at higher risk for thrombosis (age older than 60 years or a prior thrombotic event), cytoreduction with hydroxyurea significantly lowered the risk of arterial or venous thrombotic events compared with no cytoreductive therapy (3.6% vs 24%; P &amp;lt; .01). At a median of 8.5 years from diagnosis, approximately 10% of patients with essential thrombocythemia develop myelofibrosis and about 3% develop acute myeloid leukemia. Conclusions Essential thrombocythemia is a rare clonal myeloproliferative neoplasm associated with an increased risk of venous and arterial thrombosis, hemorrhage, myelofibrosis, and acute myeloid leukemia. Based on individual risk factors for thrombosis, persons with essential thrombocythemia may be treated with low-dose aspirin, either alone or in combination with a cytoreductive drug such as hydroxyurea.

ABSTRACT Patients with newly diagnosed acute myeloid leukemia (ND‐AML) derive variable survival benefit from venetoclax + hypomethylating agent (Ven‐HMA) therapy. The primary objective in the current study was to develop genetic risk models that are predictive of survival and are applicable at the time of diagnosis and after establishing treatment response. Among 400 ND‐AML patients treated with Ven‐HMA at the Mayo Clinic, 247 (62%) achieved complete remission with (CR) or without (CRi) count recovery. Multivariable analysis–derived hazard ratios (HR), including 1.8 for European LeukemiaNet (ELN) adverse karyotype, 4.7 for KMT2Ar , 1.7 for TP53 MUT , 2.6 for KRAS MUT , and 2.1 for IDH2 WT were applied to develop an HR‐weighted risk model: low, intermediate, and high; respective median survival censored for allogeneic stem cell transplant (ASCT) (3‐year survival) were “not reached” (67%), 19.1 (33%), and 7.1 months (0%). In patients achieving CR/CRi, adverse karyotype, KMT2Ar , KRAS MUT , IDH2 WT predicted inferior survival, allowing for a complementary response‐stratified risk model. The model was externally validated and was shown to be superior to the ELN 2024 risk model (AIC 179 vs. 195 and AUC 0.77 vs. 0.69). Survival was inferior with failure to achieve CR/CRi or not receiving ASCT; 3‐year survival for high‐risk with or without ASCT was 42% versus 0% ( p < 0.01); intermediate 72% versus 43% ( p = 0.06); and low‐risk 88% versus 78% ( p = 0.53). The Mayo genetic risk models offer pre‐treatment and response‐based prognostic tools for ND‐AML treated with Ven‐HMA. The current study underscores the prognostically indispensable role of achieving CR/CRi and ASCT.

Background An increased risk of second cancers (SC), in patients with myeloproliferative neoplasms (MPN), has been suggested by a number of population-based and cancer registry studies (Blood 2011;118:6515). Such studies often included patients belonging to a broad category of MPN entities and did not always account for history of cancer prior to the diagnosis of MPN, associated comorbidities, mutations, or treatments received, in assessing risk association and prediction (Leukemia 2019;33:1996). The current study seeks to fill knowledge gaps, in this regard, in the context of a biologically more homogeneous MPN setting, vis-ẚ-vis polycythemia vera (PV) and essential thrombocythemia (ET). Methods The present study was conducted under an institutional review board approved minimum risk protocol that allowed retrospective collection and analysis of data from Mayo Clinic patient records. Diagnostic criteria were according to the International Consensus Classification (Blood 2022; 140:1200). Documented primary cancers were annotated in 17 categories, not including pre-cancerous conditions or MPN progressions. SC was defined as any cancer that developed after 3 months from the initial diagnosis of MPN. Cox proportional hazard regression model was used for univariable and multivariable analysis. Kaplan-Meier plots were used for time-to-event assessment (considering the first in case of multiple events). Results The study population included 1,968 consecutive patients (median age 60 years; 56% females) with PV (N=1,001) or ET (N=967), seen at the Mayo Clinic between 1970 and 2024. Median follow-up was 8.6 years. The incidences of arterial/venous thrombosis were14%/12% at diagnosis and 12%/10% after diagnosis. Co-morbid conditions included diabetes (12%), hypertension (52%), tobacco use (16%), and history of autoimmune/inflammatory disease (AID; 6%); hyperlipidemia was annotated in PV cases only (51%). Non-driver mutation information was available in 620 patients: TET2 (13%), ASXL1 (7%), DNMT3A (5%), SRSF2 (3%), SF3B1 (3%) and TP53 (2%). A history of another cancer was documented in 598 (30%) patients and included cancers documented before/at (N=291; 15%) or after (N=404; 20%) the diagnosis of MPN, with only the latter being referred to as “SC”. Most frequent cancer type was non-melanoma skin cancer (NMSC), accounting for 28% of cancers diagnosed before/at MPN, and 47% of SC; other SC types included lymphoid neoplasms (10%), melanoma (10%), prostate cancer (9%), and trachea/lung/bronchial cancer (8%), as the most frequent. On multivariable analysis, cancer history, before/at or after MPN diagnosis, clustered with age &gt;60 years (OR 2.7), male sex (OR 1.5), and history of AID (OR 1.7). History of cancer prior to MPN diagnosis, NMSC or otherwise, was associated with inferior overall survival (p&lt;0.01); by contrast, neither myelofibrosis-free (p=0.5) nor leukemia-free (p=0.8) survival was affected. Median time from MPN diagnosis to SC was 5.7 years. In multivariable analysis including all cancers, SC-free survival was adversely affected by age&gt;60 years (HR 2.5; p&lt;0.01), male sex (HR 1.7; p&lt;0.01), history of previous cancer (HR 2.5, p&lt;0.01), and AID history (HR 1.6; p&lt;0.01); all these 4 risk factors remained significant after excluding NMSC. Interestingly, among informative cases, SRSF2 mutation also predicted SC (HR 2.6; p=0.02), even after NMSC cases were excluded (HR 3.4; p=0.02). Pre-MPN history of cancer did not affect either arterial (p=0.9) or venous thrombosis-free survival (p=0.7), in age- and sex-adjusted analysis. Conversely, after excluding post-SC thrombotic events, venous (p=0.02) but not arterial (p=0.1) events, occurring after MPN diagnosis, were predictive of SC. This association remained significant in multivariable analysis that included age, sex, and venous thrombosis history (p=0.03). Additional observations from this study, include an independent association between SC and hyperlipidemia in PV (p&lt;0.01) and ruxolitinib monotherapy with NMSC (HR 9; p&lt;0.01). Conclusions The risk of SC in patients with MPN is significantly higher in older patients, men, and in the presence of pre-MPN cancer history and AID. Incidental venous, but not arterial, thrombosis was associated with subsequent SC, not NMSC. The observed association of SC with SRSF2 mutations and hyperlipidemia is noted but requires further validation.

Background: Therapy-related myeloid neoplasms (t-MN) occur after exposure to DNA-damaging agentsincluding cytotoxic chemo and radiation therapy and are associated with dismal outcomes. TP53 and PPM1D (protein phosphatase Mn2+/Mg2+-dependent 1D) mutations (MT) disrupt the DNA damage response and repair (DDR) pathway, are often co-mutated (25-35%), and although enriched in t-MN (20%), can also be seen in age-related clonal hematopoiesis (CH) (5-10%). While progressive genomic instability with biallelic inactivation has been described as a mechanism of MN progression with TP53 MT, similar mechanisms remain to be elucidated for PPM1D MT. We conducted this study to assess the clinical phenotype and outcomes of TP53 and PPM1D co-mutated (PPM1DTP53m) versus PPM1D MT and wild type TP53 (PPM1DTP53wt) CH and MN. Methods: After approval from the Mayo Clinic IRB, the CH and MN databases were queried and 119 pts with PPM1D MT (CH= 26, clonal cytopenia of unknown significance [CCUS]= 64, myelodysplastic syndrome [MDS]=16, myeloproliferative neoplasm [MPN]=8, acute myeloid leukemia [AML]= 5) were identified. We analyzed baseline characteristics, karyotypic changes, somatic mutations, and survival outcomes between the PPM1DTP53m (n= 22) and PPM1DTP53wt (n= 97) groups (gp). Results: Baseline characteristics The median age in years (yrs) was 68.5 (range [R], 43-89) and 71 (R,30-92) in the PPM1DTP53m and PPM1DTP53wt gp (p= 0.65). 22% vs 18% (p=0.78), 58% vs 32% (p=0.03), 9% vs 32% (p=0.01), 7% vs 4.5% (p=&gt;0.99) and 3% vs 14% (p=0.07) pts met criteria for CH, CCUS, MDS, MPN and AML in the PPM1DTP53wt and PPM1DTP53m gp, respectively. Similarly, 19% vs 18% (p=&gt;0.99), 47% vs 32% (p=0.23), 7% vs 36% (p=0.001), 2% vs 0% (p=&gt;0.99) and 2% vs 14% (p=0.04) of pts met criteria for t-CH, t-CCUS, t-MDS, t-MPN and t-AML in the PPM1DTP53wt and PPM1DTP53m gp, respectively. All PPM1D variants were truncating, located in exon 6 of the gene, with median variant allele frequency (VAF) (8% [R,1-64] vs 5.5% [R,2-24], p= 0.10) and number of PPM1D MT (1 [R,1-5] vs 1 [R, 1-3], p=&gt;0.99) being similar between the two gp. While proportion of pts with t-MN were similar between the two gps (77% vs 86%, p= 0.40), cytogenetic (CG) abnormalities (67% vs 31%, p= 0.006), including monosomies (28% vs 2%, p= &lt;0.001) and complex CG (53% vs 4%, p= &lt;0.001) were more frequent in PPM1DTP53m gp compared to PPM1DTP53wt gp, respectively. The median TP53 MT VAF was 14% (R, 1-14); 50% had multi-hit TP53 MT. Somatic mutations in PPM1D MT myeloid neoplasm with and without TP53 MT Somatic co-mutations excluding TP53 were seen in 71% of pts; 73.5% in PPM1DTP53wt and 59% in PPM1DTP53m gp (p= 0.20). Apart from CBL (0% vs 9%,p=0.03), MT involving DNMT3A (20% vs 14%, p= 0.56), TET2 (15% vs. 14%, p= &gt;0.99), IDH1 (6% vs 19%, p= 0.07), splicing factors (8% vs 14%, p=0.08), ASXL1 (11% vs 4.5%, p=0.46), and JAK2 (9% vs 0%,p=0.20) were comparable between PPM1DTP53wt and PPM1DTP53m gps, respectively. The proportion of pts with ≥ 2 somatic co-mutations excluding TP53 MT were numerically higher in PPM1DTP53wt gp (43%) compared to PPM1DTP53m gp (23%) (p= 0.09). In the PPM1DTP53wt gp, other somatic driver mutations included RUNX1 (n= 7 [7%]; CH [n=1], CCUS [n=2], MDS [n=3], MPN [n=1]), NRAS (n=1 [1%]; CCUS), BCOR (n=1 [1%]; CCUS), and PTPN11 (n=1 [1%]; CCUS). Leukemic transformation and survival With a median follow up of 6.43 months (mo) (R, 0.23-36.4), median overall survival (mOS) in mo among high-risk MDS/AML (16.4 vs 15.0, p= 0.66) and CHIP/CCUS pts (35.79 vs 26.28, p= 0.93) was similar between PPM1DTP53wt and PPM1DTP53m gps, respectively. CHIP/CCUS pts harboring multiple vs single PPM1D MT had an inferior mOS (23.9 vs 36.7 mo, p= 0.05). Three (2.5%) MDS pts underwent AML transformation; 1 (1%) and 2 (10%) in PPM1DTP53wt and PPM1DTP53m gp, respectively (p= 0.07). Conclusions In our study, 18% of pts had concurrent TP53 and PPM1D MT (82% t-MN), with the PPM1DTP53wt genotype being more frequent in CCUS, while the PPM1DTP53m genotype was more frequent in MN. The PPM1DTP53m genotype had a higher frequency of CG abnormalities, including complex CG. Survival outcome was inferior and comparable in PPM1D MT MN with or without TP53 MT. While 73.5 % of the PPM1DTP53wt gp had somatic driver MT and 31% had karyotypic abnormalities, 22% had no additional MT or CG changes (all CH/CCUS), underscoring the need to understand how PPM1D MT contribute to hematopoietic dysfunction and MN.

Background: The majority of patients with chronic myelomonocytic leukemia (CMML) harbor somatic mutations with the most frequent being TET2 (56%), SRSF2 (42%), and ASXL1 (41%) (Leukemia 2020;34:1407). The prognostic relevance of mutations in CMML has been studied extensively with consistent observations suggesting favorable survival impact from TET2 and unfavorable from DNMT3A, ASXL1, NRAS, and SETBP1 mutations. Among the latter, DNMT3A mutation stands out as being the strongest predictor of inferior overall (OS) and leukemia-free (LFS) survival (AJH 2017;92:56). The current study was inspired by observations from exploratory analyses of a large Mayo Clinic CMML cohort. Methods: The current retrospective study was conducted under an institutional review board approved minimum risk protocol that allowed retrospective collection and analysis of data from patient records (Mayo Clinic, Rochester, MN; Scottsdale, AZ; and Jacksonville, FL). Mutations were screened by multi-gene next-generation sequencing (NGS). Diagnostic criteria were according to the International Consensus Classification (Blood 2022; 140:1200). Conventional statistical methods were employed for comparisons of groups and survival analysis (JMP Pro 17.0.0 software SAS Institute, Cary, NC, USA). Results: Exploratory analysis of a well-characterized cohort of 398 Mayo Clinic patients with CMML suggested an unusually long median survival of 96 months for 7 patients harboring PHF6 mutation vs. 27 months for those without the mutation. A subsequent institutional database search focusing on PHF6-mutated CMML identified 20 more cases, expanding the total number of study patients to 418, including 27 PHF6-mutated cases. PHF6 mutations clustered with (co-mutation frequency) TET2 (93%) and less likely to be co-mutated with TP53 (0%), PTPTN11 (0%) and SF3B1 (0%) mutations. PHF6-mutated patients often presented with thrombocytopenia (platelet count &lt;100 x 10(9)/L; 85% vs. 51% in PHF6 wild-type cases; p&lt;0.01). Median time from initial presentation with thrombocytopenia to CMML diagnosis was 4 years (0-14 years). In order to isolate the prognostic impact of PHF6 mutation without associated DNMT3A mutation and independent of TET2 mutation, we considered 4 mutational categories: i) DNMT3A-mutated (N=19; 2 co-expressed PHF6 and 7 TET2 mutations), ii) PHF6-mutated with wild-type DNMT3A (N=25; 23 co-expressed TET2 mutation), iii) TET2-mutated without DNMT3A or PHF6 co-expression (N=169), and iv) wild-type for DNMT3A, TET2, and PHF6 (N=205). Compared to the other groups, PHF6-mutated patients with wild-type DNMT3A were less likely to display leukocytosis (p&lt;0.01) or red cell transfusion need at presentation (p&lt;0.01). At a median follow-up of 18 months, 302 deaths, 78 leukemic transformations, and 44 allogenic stem cell transplants were documented. Univariate analysis for OS disclosed superiority in favor of PHF6-mutated patients with wild-type DNMT3A (median OS 90 months) vs. the other three groups with median OS ranging from 10 months for DNMT3A-mutated patients (HR 20.7, 95% CI 8.1-52.7; p&lt;0.01) to 40 months for TET2-mutated cases with wild-type DNMT3A (HR 3.5, 95% CI 1.7-7.6; p&lt;0.01). Results were similar for multivariable analysis of LFS, where, remarkably, none (0%) of the 25 PHF6-mutated patients with wild-type DNMT3A experienced leukemic transformation vs. 15-30% risk of leukemic transformation in the other three groups (p&lt;0.01). Multivariable analysis for both OS and LFS, which included other risk factors such as red cell transfusion need, leukocytosis (leukocyte count ≥13 x 109/L) and karyotype, confirmed the independent and favorable impact of PHF6 mutation/wild-type DNMT3A (p&lt;0.01 in both instances). Finally, all-inclusive multivariable analysis of karyotype and mutations, in DNMT3A wild-type patients, confirmed the highly favorable and independent prognostic impact of PHF6 mutation (HR 0.18, 95% CI 0.09-0.37). Conclusion: The current study proposes a 2-gene genomic signature (PHF6 mutated and DNMT3A wild-type) to identify a unique subset of CMML patients who often present with thrombocytopenia and whose clinical course is characterized by a very low risk of leukemic transformation, resulting in superior overall survival. Additional studies are warranted to validate these findings and include the information in contemporary risk models.

Introduction Chronic myelomonocytic leukemia (CMML) is associated with a 15-30% risk for blast transformation (BT) over 3-5 years. Post-BT survival remains dismal with a median overall survival (mOS) of ~6 months (mo), even with intensive therapies. Although genetic drivers are identified in &gt;40% of BT-CMML cases (Carr, 2021), mechanisms of BT remain to be elucidated. This multicenter study examines risk factors for BT in CMML and predictors of post-BT survival. Methods CMML patients at Mayo Clinic (n = 400, 47%) and MD Anderson Cancer Center (n = 449, 53%) were included with IRB approval. Analyses used clinical and molecular data at diagnosis or first referral in chronic phase (CP) and again at BT. Categorical variables were compared by Chi squared and continuous by Mann-Whitney U or Kruskal-Wallis tests. Multivariate analyses used Cox proportional hazards models with binarization via receiver operator curves. Kaplan-Meier analyses were censored at hematopoietic cell transplantation (HCT). P &lt; 0.05 was considered significant. Calculations used BlueSky (v10.3.1) or Prism (v10.2.3). Results Of 849 CMML patients (median age 71 years, 32% female, 90% white) included in the study, 133 (16%) underwent BT. In comparison to CP-CMML without BT, those with BT were more likely (p &lt; 0.05) to have had higher WBC counts (15.1 vs 11.4 x109/L), higher absolute monocyte counts (2.9 vs 2.2 x109/L), lower platelet counts (84 vs 102 x109/L), have circulating immature myeloid cells (52% vs 37%), and be classified as myeloproliferative (MP)-CMML (58% vs 44%) or CMML-2 (33% vs 17%) at diagnosis/first referral in CP. More mutations were detected in BT-CMML than in CP-CMML (mean 3.2 vs 2.8, p = 0.002). Mutations in RAS (NRAS, KRAS, BRAF, CBL, PTPN11; 51% vs 40%, p = 0.02) and signaling (CSF3R, FLT3, JAK2, SH2B3; 15% vs 7%, p = 0.004) pathway genes were more frequent in BT-CMML. Conversely, there were fewer BT-CMML patients with the favorable ASXL1WT/TET2MT genotype compared to CP-CMML (22% vs 33%, p = 0.004). Multivariate analysis identified MP-CMML (hazard ratio [HR] 1.5, p = 0.04), CMML-2 (HR 2.4, p &lt; 0.001), and the presence of ≥4 somatic gene mutations (HR 1.8, p = 0.002) as risk factors for BT whereas the ASXL1WT/TET2MTgenotype was protective (HR 0.45, p = 0.002). The ASXL1WT/TET2MT genotype was also protective in the MP-CMML (HR 0.49, p = 0.04) and RAS-mutated (HR 0.35, p = 0.005) subgroups. Amongst BT-CMML cases, the median time to BT was 10 mo from diagnosis/referral. Compared to their CP assessment, patients in an overlapping Mayo Clinic BT-CMML cohort (n = 156, median age 69 years, 35% female) were more likely to have NPM1 (24% vs 3%, p &lt; 0.001) and IDH2 (14% vs 1%, p = 0.01) mutations at BT. Amongst cases with paired molecular evaluations (n = 44), 7 (16%) acquired new mutations, including FLT3-ITD (n = 2) and NPM1 (n = 2). Conversely, 6 (14%) lost mutations, including TET2 (n = 3), SRSF2 (n = 2), CBL, NRAS, or PTPN11 (n = 1 each). There were no differences in variant allele fractions in driver genes present at CP and BT. Abnormal karyotypes were more prevalent at BT than in CP (60% vs 34%, p &lt; 0.001), and 26 (25%) patients with a normal karyotype in CP acquired structural (65%) and/or numerical (69%) changes at BT, including 6 (23%) that acquired a complex karyotype. Acute myeloid leukemia defining translocations were seen in 4 (4%) cases: 2 with t(8;21) and 1 each with inv(3) and t(10;11)(KMT2A::TET1). After considering mutation and karyotype changes, only bone marrow blasts ≥30% (HR 1.7, p = 0.04) were independently prognostic for OS after BT (mOS 4 mo). Compared to supportive care (n = 50, mOS 1.3 mo), OS was improved by hypomethylating agents (HMA, n = 14, mOS 16 mo, HR 0.3, p &lt; 0.001) or induction chemotherapy (n = 56, mOS 8 mo, HR 0.3, p &lt; 0.001), but not by HMA + venetoclax (n = 11, mOS 6 mo, HR 0.7, p = 0.4). Allogeneic HCT (n = 28) improved mOS to 46 vs 3 mo (p &lt; 0.001). Amongst 4 patients with paired whole genome sequencing before and after BT, 3 had increased copy number alterations (including 2 with loss of heterozygosity, 2 with gains, and 3 with deletions) while the 4th acquired novel likely pathogenic somatic mutations (MUC4, BAX, WNK2). Conclusions Survival in CMML after BT remains exceptionally poor. In this multicenter cohort, MP-CMML, CMML-2, and the presence of ≥4 somatic gene mutations were identified as risk factors for BT, with the ASXL1WT/TET2MT genotype being protective. Following BT, bone marrow blast burden ≥30% was an independent adverse predictor of survival.

Background: TP53-mutated (TP53mut) myeloid neoplasms (MN) have particularly poor survival. Discrepancies in defining TP53mut MN have impact on diagnostic work up, therapeutic decisions, and clinical trial enrolment. Methods: MN cases harboring TP53mut (variant allele frequency, VAF ≥2%) were classified based on bone marrow (BM) and peripheral blood (PB) blast % using the 4th revision of the WHO classification (WHO-4R). Biallelic loss was defined as (i) ≥2 mutations each with VAF ≥2%; (ii) single TP53mut VAF ≥2% plus 17p loss detected on karyotype, FISH, or SNP; or (iii) single TP53mut VAF ≥50%, whereas monoallelic loss was defined as single TP53mut VAF &lt;50% without 17p loss. Primary endpoint was overall survival (OS) from diagnosis. Conditional Inference Trees (CIT) analysis was used to determine the true effect of a predictor. Results: We identified 580 cases including WHO-4R defined acute myeloid leukemia (AML, BM/PB blasts ≥20%, n=219, 37.8%), myelodysplastic syndrome (MDS) with excess blasts-2 (EB-2, BM 10-19% or PB 5%-19%, n=92, 15.9%), MDS with excess blasts-1 (EB-1, BM 5-9% or PB 2-4%, n=75, 12.9%), and the remaining were MDS with low blasts (-LB, BM &lt;5% and PB ≤1%, n=194, 33.4%). Of the 578 cases evaluable for allelic status, 437 (75.6%) and 141 (24.4%) had biallelic and monoallelic TP53 loss, respectively. Higher frequency of biallelic loss was observed with increasing blasts. 63.2%, 73.3%, 78% and 86.3% of cases with MDS-LB, MDS-EB1, MDS-EB2, and AML had bi-allelic TP53 loss (P&lt;0.0001). In a multivariable analysis, WHO-4R categories, VAF ≥10%, and biallelic loss were independent predictors of poor survival. CIT analysis further stratified the cohort into 4 groups with distinct survival: (1) MDS-LB (n=194, 33.4%); (2) MDS-EB1/EB2 and AML with VAF &lt;10% (n=38, 6.6%); (3) MDS-EB1/EB2 with VAF ≥10% (n=149, 25.7%); and (4) AML with VAF ≥10% (n=199, 34.3%). MDS-LB cases could be further stratified based on allelic status and complex karyotype (CK): OS was poor for cases with biallelic TP53 loss and monoallelic TP53mut with CK compared to monoallelic TP53mut without CK, who had the most favorable survival (12.7 vs. 13 vs. 34.8 months, P&lt;0.0001).MDS-EB1/EB2/AML with VAF&lt;10% could also be stratified by CK: MDS-EB1/EB2/AML with VAF&lt;10% cases without CK had the favorable survival compared to their counterparts with CK and MDS-EB1/EB2 with VAF ≥10% cases (26.2 vs. 5.6 vs. 6.3 months, P=0.003).MDS-EB1/EB2 with VAF ≥10% was a homogenous subgroup: Biological characteristics including the proportion of cases with biallelic TP53 loss, CK (P&gt;0.9), monosomal karyotype (MK, P&gt;0.9), del 5q (P=0.6), del 7q (P=0.4), and del 17p (P=0.2) were comparable between MDS-EB1 and -EB2 with VAF ≥10%. Importantly, median OS of MDS-EB1 and EB2 with VAF ≥10% was comparable (9.6 vs. 7.2 months, P=0.12). OS in this group was comparable regardless of the blast %, allelic status, or presence of CK.AML with VAF ≥10% had extremely poor survival: Median OS was 3.9 months. Survival of AML was equally poor irrespective of the mono- or biallelic (3.6 vs. 3.9, P=0.89) and non-CK vs. CK (1.8 vs. 3.9 months, P=0.09). Combined, our model would acknowledge poor survival of 514 (89.1%) cases. In contrast, retrospective application of the 5th edition of the WHO classification (WHO-5) and International Consensus Classification (ICC) would classify only 211 (36.4%) and 468 (80.7%) cases as biallelic/multi-hit TP53mut MN, respectively. Finally, the Harrell's c-index of the proposed model, WHO-5, and ICC was 0.66, 0.571, and 0.617, respectively. Conclusion: We provide evidence for subsequent refinements in classifying MN harboring TP53mut. Our salient findings include: (i) acknowledgement of CK as ‘biallelic equivalent’ in MDS-LB; as well as EB1/EB2/AML with VAF 2 to &lt;10% cases; and (ii) demonstration of poor survival of MDS-EB1 and -EB2 with VAF ≥10% regardless of the allelic status. In conclusion, our proposed model acknowledged poor survival of a higher proportion of cases as TP53mut MN compared to the current models with a higher c- index.