RAS-mutant leukaemia stem cells drive clinical resistance to venetoclax.

Cancer driver mutations often show distinct temporal acquisition patterns, but the biological basis for this, if any, remains unknown. RAS mutations occur invariably late in the course of acute myeloid leukaemia, upon progression or relapsed/refractory disease1-6. Here, by using human leukaemogenesis models, we first show that RAS mutations are obligatory late events that need to succeed earlier cooperating mutations. We provide the mechanistic explanation for this in a requirement for mutant RAS to specifically transform committed progenitors of the myelomonocytic lineage (granulocyte-monocyte progenitors) harbouring previously acquired driver mutations, showing that advanced leukaemic clones can originate from a different cell type in the haematopoietic hierarchy than ancestral clones. Furthermore, we demonstrate that RAS-mutant leukaemia stem cells (LSCs) give rise to monocytic disease, as observed frequently in patients with poor responses to treatment with the BCL2 inhibitor venetoclax. We show that this is because RAS-mutant LSCs, in contrast to RAS-wild-type LSCs, have altered BCL2 family gene expression and are resistant to venetoclax, driving clinical resistance and relapse with monocytic features. Our findings demonstrate that a specific genetic driver shapes the non-genetic cellular hierarchy of acute myeloid leukaemia by imposing a specific LSC target cell restriction and critically affects therapeutic outcomes in patients.

How I Treat: Differentiation Therapy in Acute Myeloid Leukemia.

An increasing number of acute myeloid leukemia (AML) therapeutics have been developed, not as cytotoxic therapies, but rather as targeted agents able to restore the aberrant and leukemogenic "block" in normal differentiation. All-trans retinoic acid (ATRA) and arsenic trioxide (ATO) are classic examples of differentiating agents for treatment of acute promyelocytic leukemia (APL); newer therapies functioning through differentiation include isocitrate dehydrogenase (IDH) 1 and 2 inhibitors, FMS-like tyrosine kinase 3 (FLT3) inhibitors, and menin inhibitors. The terminal differentiation of leukemic blasts via differentiating agent therapy can lead to a constellation of signs and symptoms, originally referred to as "retinoic acid syndrome" and now termed "differentiation syndrome" (DS), characterized predominantly by systemic inflammatory response system (SIRS)-like features of dyspnea, pulmonary infiltrates, pleural and pericardial effusions, unexplained fevers, hypotension, edema, and renal insufficiency. DS in patients with newly diagnosed APL is generally straightforward to identify, however DS in patients with multiply relapsed AML can be more challenging to diagnose, due to non-specific signs and symptoms which can be mistakenly attributed to infectious etiologies or the underlying refractory leukemia itself. Prompt consideration of DS, rapid initiation of systemic corticosteroids, and early cytoreduction in the setting of concomitant hyperleukocytosis, are essential for optimal management.

Phase 2 study of inotuzumab ozogamicin for measurable residual disease in acute lymphoblastic leukemia in remission.

ABSTRACT: The detection of measurable residual disease (MRD) is the strongest predictor of relapse in acute lymphoblastic leukemia (ALL). Using inotuzumab ozogamicin in the setting of MRD may improve outcomes. Patients with ALL in first complete remission (CR1) or beyond (CR2+) with MRD ≥ 1 × 10-4 were enrolled in this phase 2 trial. Inotuzumab was administered at 0.6 mg/m2 on day 1 and 0.3 mg/m2 on day 8 of cycle 1, then at 0.3 mg/m2 on days 1 and 8 of cycles 2-6. Twenty-six consecutive patients with a median age of 46 years (range, 19-70 years) were treated. Nineteen (73%) were in CR1 and seven (27%) in CR2+; 16 (62%) had Philadelphia chromosome-positive ALL. Fifteen (58%) had baseline MRD ≥ 1 × 10-3. A median of 3 cycles (range, 1-6) were administered. Eighteen (69%) patients responded and achieved MRD negativity. After a median follow-up of 24 months (range, 9-43), the 2-year relapse-free survival rate was 54% and the 2-year overall survival rate was 60% in the entire cohort. Most adverse events were low grade; sinusoidal obstruction syndrome was noted in 2 patients (8%). In summary, inotuzumab ozogamicin resulted in favorable survival, MRD negativity rates, and safety profiles for patients with ALL and MRD-positive status. This study was registered at www.ClinicalTrials.gov as #NCT03441061.

BRG1/BRM inhibitor targets AML stem cells and exerts superior preclinical efficacy combined with BET or menin inhibitor.

ABSTRACT: BRG1 (SMARCA4) and BRM (SMARCA2) are the mutually exclusive core ATPases of the chromatin remodeling BAF (BRG1/BRM-associated factor) complexes. They enable transcription factors/cofactors to access enhancers/promoter and modulate gene expressions responsible for cell growth and differentiation of acute myeloid leukemia (AML) stem/progenitor cells. In AML with MLL1 rearrangement (MLL1r) or mutant NPM1 (mtNPM1), although menin inhibitor (MI) treatment induces clinical remissions, most patients either fail to respond or relapse, some harboring menin mutations. FHD-286 is an orally bioavailable, selective inhibitor of BRG1/BRM under clinical development in AML. Present studies show that FHD-286 induces differentiation and lethality in AML cells with MLL1r or mtNPM1, concomitantly causing perturbed chromatin accessibility and repression of c-Myc, PU.1, and CDK4/6. Cotreatment with FHD-286 and decitabine, BET inhibitor (BETi) or MI, or venetoclax synergistically induced in vitro lethality in AML cells with MLL1r or mtNPM1. In models of xenografts derived from patients with AML with MLL1r or mtNPM1, FHD-286 treatment reduced AML burden, improved survival, and attenuated AML-initiating potential of stem-progenitor cells. Compared with each drug, cotreatment with FHD-286 and BETi, MI, decitabine, or venetoclax significantly reduced AML burden and improved survival, without inducing significant toxicity. These findings highlight the FHD-286-based combinations as a promising therapy for AML with MLL1r or mtNPM1.

Genetic Risk Stratification and Outcomes Among Treatment-Naive Patients With AML Treated With Venetoclax and Azacitidine.

European LeukemiaNet (ELN) acute myeloid leukemia (AML) genetic risk classification systems were based on response to intensive chemotherapy; their ability to discriminate outcomes in older patients treated with venetoclax-azacitidine may be suboptimal. Here, pooled analysis of patients in the phase 3 VIALE-A trial (NCT02993523) and phase 1b study (NCT02203773) examined prognostic stratification according to 2017 and 2022 ELN risk classifications. A bioinformatic algorithm derived new molecular signatures differentiating venetoclax-azacitidine-treated patients based on median overall survival (OS). 279 patients treated with venetoclax-azacitidine and 113 patients treated with placebo-azacitidine were analyzed. When classified by ELN 2017 or 2022 prognostic criteria, most patients had adverse-risk AML (60.2% and 72.8% for venetoclax-azacitidine and 65.5% and 75.2% for placebo-azacitidine, respectively). While outcomes with venetoclax-azacitidine were improved across all ELN risk groups compared with placebo-azacitidine, ELN classification systems poorly discriminated venetoclax-azacitidine outcomes. By applying a bioinformatic algorithm, new molecular signatures were derived differentiating OS outcomes with venetoclax-azacitidine; the mutational status of TP53, FLT3-ITD, NRAS, and KRAS categorized patients into higher-, intermediate-, and lower-benefit groups (52%, 25%, and 23% of patients, respectively), each associated with a distinct median OS (26.5 months [95% CI, 20.2 to 32.7], 12.1 months [95% CI, 7.3 to 15.2], and 5.5 months [95% CI, 2.8 to 7.6], respectively). ELN prognostic classifiers do not provide clinically meaningful risk stratification of OS outcomes for patients with AML treated with venetoclax-azacitidine. TP53, FLT3-ITD, NRAS, and KRAS mutation status allows classification of these patients into three risk groups with distinct differences in median OS.

Genetic risk classification for adults with AML receiving less-intensive therapies: the 2024 ELN recommendations.

The European LeukemiaNet (ELN) genetic risk classifications were developed based on data from younger adults receiving intensive chemotherapy. Emerging analyses from patients receiving less-intensive therapies prompted a proposal for an ELN genetic risk classification specifically for this patient population.

Clonal landscape and clinical outcomes of telomere biology disorders: somatic rescuing and cancer mutations.

Telomere biology disorders (TBD), caused by pathogenic germline variants in telomere-related genes, present with multi-organ disease and a predisposition to cancer. Clonal hematopoiesis (CH) as a marker of cancer development and survival in TBD is poorly understood. Here, we characterized the clonal landscape of a large cohort of 207 TBD patients with a broad range of age and phenotype. CH occurred predominantly in symptomatic patients and in signature genes typically associated with cancers: PPM1D, POT1, TERT promoter (TERTp), U2AF1S34, and/or TP53. Chromosome 1q gain (Chr1q+) was the commonest karyotypic abnormality. Clinically, multiorgan involvement and CH in TERTp, TP53, and splicing factor genes associated with poorer overall survival. Chr1q+, and splicing factor or TP53 mutations significantly increased the risk of hematologic malignancies, regardless of the clonal burden. Chr1q+ and U2AF1S34 mutated clones were pre-malignant events associated with the secondary acquisition of mutations in genes related to hematologic malignancies. Like known effects of Chr1q+ and TP53-CH, functional studies demonstrated that U2AF1S34 mutations primarily compensated for aberrant upregulation of TP53 and interferon pathways in telomere-dysfunctional hematopoietic stem cells, highlighting the TP53 pathway as a canonical route of malignancy in TBD. In contrast, somatic POT1/PPM1D/TERTp-CH had distinct trajectories unrelated to cancer development. With implications beyond TBD, our data show that telomere dysfunction is a strong selective pressure for CH. In TBD, CH is a poor prognostic marker associated with worse overall survival. The identification of key regulatory pathways that drive clonal transformation in TBD allows the identification of patients at a higher risk of cancer development.

Venetoclax abrogates the prognostic impact of splicing factor gene mutations in newly diagnosed acute myeloid leukemia.

Mutations in splicing factor (SF) genes SRSF2, U2AF1, SF3B1, and ZRSR2 are now considered adverse risk in the European LeukemiaNet 2022 acute myeloid leukemia (AML) risk stratification. The prognostic impact of SF mutations in AML has been predominantly derived from younger patients treated with intensive (INT) therapy. We evaluated 994 patients with newly diagnosed AML, including 266 (27%) with a SFmut. Median age was 67 years overall, with patients with SFmut being older at 72 years. SRSF2 (n = 140, 53%) was the most common SFmut. In patients treated with INT, median relapse-free survival (RFS) (9.6 vs 21.4 months, P = .04) and overall survival (OS) (15.9 vs 26.7 months, P = .06) were shorter for patients with SFmut than without SFwt, however this significance abrogated when evaluating patients who received venetoclax with INT therapy (RFS 15.4 vs 20.3 months, P = .36; OS 19.6 vs 30.7 months, P = .98). In patients treated with LI, median RFS (9.3 vs 7.7 months, P = .35) and OS (12.3 vs 8.5 months, P = .14) were similar for patients with and without SFmut , and outcomes improved in all groups with venetoclax. On multivariate analysis, SFmut did not affect hazards of relapse and death for INT arm but reduced both these hazards in LI arm. In a large AML data set with >60% of patients receiving venetoclax with LI/INT therapy, SFmut had no independent negative prognostic impact. Newer prognostic models that consider LI therapy and use of venetoclax among other factors are warranted.

Enasidenib vs conventional care in older patients with late-stage mutant-IDH2 relapsed/refractory AML: a randomized phase 3 trial.

This open-label, randomized, phase 3 trial (NCT02577406) compared enasidenib, an oral IDH2 (isocitrate dehydrogenase 2) inhibitor, with conventional care regimens (CCRs) in patients aged ≥60 years with late-stage, mutant-IDH2 acute myeloid leukemia (AML) relapsed/refractory (R/R) to 2 or 3 prior AML-directed therapies. Patients were first preselected to a CCR (azacitidine, intermediate-dose cytarabine, low-dose cytarabine, or supportive care) and then randomized (1:1) to enasidenib 100 mg per day or CCR. The primary endpoint was overall survival (OS). Secondary endpoints included event-free survival (EFS), time to treatment failure (TTF), overall response rate (ORR), hematologic improvement (HI), and transfusion independence (TI). Overall, 319 patients were randomized to enasidenib (n = 158) or CCR (n = 161). The median age was 71 years, median (range) enasidenib exposure was 142 days (3 to 1270), and CCR was 36 days (1 to 1166). One enasidenib (0.6%) and 20 CCR (12%) patients received no randomized treatment, and 30% and 43%, respectively, received subsequent AML-directed therapies during follow-up. The median OS with enasidenib vs CCR was 6.5 vs 6.2 months (HR [hazard ratio], 0.86; P = .23); 1-year survival was 37.5% vs 26.1%. Enasidenib meaningfully improved EFS (median, 4.9 vs 2.6 months with CCR; HR, 0.68; P = .008), TTF (median, 4.9 vs 1.9 months; HR, 0.53; P < .001), ORR (40.5% vs 9.9%; P <.001), HI (42.4% vs 11.2%), and red blood cell (RBC)-TI (31.7% vs 9.3%). Enasidenib safety was consistent with prior reports. The primary study endpoint was not met, but OS was confounded by early dropout and subsequent AML-directed therapies. Enasidenib provided meaningful benefits in EFS, TTF, ORR, HI, and RBC-TI in this heavily pretreated older mutant-IDH2 R/R AML population.

Ivosidenib significantly reduces triazole levels in patients with acute myeloid leukemia and myelodysplastic syndrome.

BACKGROUND: Ivosidenib is primarily metabolized by CYP3A4; however, it induces CYP450 isozymes, including CYP3A4 and CYP2C9, whereas it inhibits drug transporters, including P-glycoprotein. Patients with acute myeloid leukemia are at risk of invasive fungal infections, and therefore posaconazole and voriconazole are commonly used in this population. Voriconazole is a substrate of CYP2C9, CYP2C19, and CYP3A4; therefore, concomitant ivosidenib may result in decreased serum concentrations. Although posaconazole is a substrate of P-glycoprotein, it is metabolized primarily via UDP glucuronidation; thus, the impact of ivosidenib on posaconazole exposure is unknown. METHODS: Patients treated with ivosidenib and concomitant triazole with at least one serum trough level were included. Subtherapeutic levels were defined as posaconazole <700 ng/mL and voriconazole <1.0 µg/mL. The incidences of breakthrough invasive fungal infections and QTc prolongation were identified at least 5 days after initiation of ivosidenib with concomitant triazole. RESULTS: Seventy-eight serum triazole levels from 31 patients receiving ivosidenib-containing therapy and concomitant triazole were evaluated. Of the 78 concomitant levels, 47 (60%) were subtherapeutic (posaconazole: n = 20 of 43 [47%]; voriconazole: n = 27 of 35 [77%]). Compared to levels drawn while patients were off ivosidenib, median triazole serum levels during concomitant ivosidenib were significantly reduced. There was no apparent increase in incidence of grade 3 QTc prolongation with concomitant azole antifungal and ivosidenib 500 mg daily. CONCLUSIONS: This study demonstrated that concomitant ivosidenib significantly reduced posaconazole and voriconazole levels. Voriconazole should be avoided, empiric high-dose posaconazole (>300 mg/day) may be considered, and therapeutic drug monitoring is recommended in all patients receiving concomitant ivosidenib.

NPM1-mutated myeloid neoplasms are a unique entity not defined by bone marrow blast percentage.

INTRODUCTION: NPM1-mutated (NPM1mut) myeloid neoplasms (MNs) with <20% bone marrow (BM) blasts (NPM1mut MNs<20) are uncommon, and their classification remains inconsistent. METHODS: The clinicopathologic features of 54 patients with NPM1mut MNs <20 were evaluated and compared with wild-type NPM1 MNs <20 and NPM1mut MNs≥20, respectively. RESULTS: NPM1mut MNs had similar features regardless of blast percentage, except for higher IDH2 (29% vs 7%, p = .023) and FLT3 (70% vs 11%, p < .001) frequency in patients with ≥20% BM blasts. Thirty-three (61%) patients with NPM1mut MNs <20 received low-intensity chemotherapy (LIC) and 12 (22%) received intensive chemotherapy (IC). Higher complete remission rates (75% vs 27%, p = .006) and median overall survival (mOS) (not reached vs 30.4 months, p = .06) were observed with IC compared to LIC. Young patients (age <60 years) did not reach mOS either when treated with LIC or IC. Stem cell transplant was associated with increased survival only in patients treated with LIC (HR, 0.24; p = .025). No differences in mOS were observed by BM blast strata (32.2 months, not reached and 46.9 months for <10%, 10%-19%, and ≥20% blasts, p = .700) regardless of treatment modality (LIC: p = .900; IC: p = .360). Twenty-three patients (43%) with NPM1mut MNs <20 had marrow blast progression to ≥20%. CONCLUSIONS: Overall, NPM1mut MNs define a unique entity independent of BM blast percentage.

Lower intensity therapy with cladribine/low dose cytarabine/venetoclax in older patients with acute myeloid leukemia compares favorably with intensive chemotherapy among patients undergoing allogeneic stem cell transplantation.

BACKGROUND: Allogeneic stem cell transplantation (SCT) remains the best consolidative modality in most patients with acute myeloid leukemia (AML). Along with factors directly pertaining to SCT, pretransplantation disease control, performance status, and prior treatment-related complications are important factors that affect posttransplantation survival outcomes. METHODS: The authors compared the survival outcomes of patients ≥60 years of age treated on the phase 2 clinical trial of venetoclax (Ven) added to cladribine (CLAD) and low dose cytarabine (LDAC) alternating with azacitidine (CLAD/LDAC/Ven arm) (NCT03586609) who underwent allogeneic SCT in first remission to a retrospective cohort of patients ≥60 years of age who underwent SCT after intensive chemotherapy. Intensive chemotherapy was defined as the use of cytarabine >1 g/m2 and anthracyclines during induction/consolidation. RESULTS: Thirty-five patients at median age of 68 years in the CLAD/LDAC/Ven arm were compared to 42 patients at a median age of 62 years in the intensive therapy arm. The 2-year relapse-free survival was superior with CLAD/LDAC/Ven versus intensive chemotherapy (88% vs. 65%; p = .03) whereas the 2-year overall survival (OS) was comparable (84% vs. 70%; p = .14). On a competing event analysis, the 2-year cumulative incidence of relapse (CIR) was significantly lower with CLAD/LDAC/Ven versus intensive chemotherapy (2.9% vs. 17.2%, Gray's p = .049) whereas nonrelapse mortality was comparable (16.2% vs. 17.1%; p = .486). CONCLUSION: In conclusion, treatment with CLAD/LDAC/Ven was associated with favorable outcomes in older patients who underwent subsequent allogeneic SCT. The OS was comparable to that with intensive chemotherapy followed by allogeneic SCT, but the CIR rate was significantly lower.

Oral decitabine-cedazuridine in acute myeloid leukaemia.

In a randomized crossover study involving 89 patients with acute myeloid leukaemia ineligible for intensive chemotherapy, Geissler et al. compared intravenous decitabine and oral decitabine-cedazuridine. The pharmacokinetics and pharmacodynamics of the two formulations were similar. The clinical efficacy of oral decitabine-cedazuridine was consistent with historical data of intravenous decitabine. Commentary on: Geissler et al. Oral decitabine/cedazuridine versus intravenous decitabine for acute myeloid leukaemia: A randomised, crossover, registration, pharmacokinetics study. Br J Haematol 2024 (Online ahead of print). doi: 10.1111/bjh.19741.

Characteristics and outcomes of acute myeloid leukaemia patients with baseline CD7 expression.

Targeted therapy development for acute myeloid leukaemia (AML) requires an understanding of specific expression profiles. We collected flow cytometry data on 901 AML patients and recorded aberrant CD7 expression on leukaemic blasts. 263 (29.2%) had blasts positive for CD7. CD7+ AML was more likely to be adverse risk (64.6% vs. 55.6%, p = 0.0074) and less likely to be favourable risk (15.2% vs. 24.1%, p = 0.0074) by European LeukemiaNet 2022 criteria. Overall survival was inferior (11.9 [95% CI, 9.7-15.9] vs. 19.0 months [95% CI, 16.1-23.0], p = 0.0174). At relapse, 30.4% lost and 19.0% gained CD7, suggesting moderate instability over time.

Combination therapy with novel agents for acute myeloid leukaemia: Insights into treatment of a heterogenous disease.

The treatment landscape of acute myeloid leukaemia (AML) is evolving rapidly. Venetoclax in combination with intensive chemotherapy or doublets or triplets with targeted or immune therapies is the focus of numerous ongoing trials. The development of mutation-targeted therapies has greatly enhanced the treatment armamentarium, with FLT3 inhibitors and isocitrate dehydrogenase inhibitors improving outcomes in frontline and relapsed/refractory (RR) AML, and menin inhibitors showing efficacy in RR NPM1mut and KMT2A-rearranged AML. With so many new drugs approved, the number of potential combinatorial approaches to leverage the maximal benefit of these agents has increased dramatically, while at the same time introducing clinical challenges, such as key preclinical and clinical data supporting the development of combinatorial therapy, how to optimally combine or sequence these novel agents, how to optimise dose and duration to maintain safety while enhancing efficacy, the optimal duration of therapy and the role of measurable residual disease in decision-making in both intensive and low-intensity therapy settings. In this review, we will outline the evidence leading to the approval of key agents in AML, their on-label current approvals and how they may be optimally combined in a safe and deliverable fashion to further improve outcomes in AML.

Acute myeloid leukaemia.

Progress in acute myeloid leukaemia treatment is occurring at an unprecedented pace. The past decade has witnessed an increasingly improved scientific understanding of the underlying biology of acute myeloid leukaemia, leading to enhanced prognostication tools and refined risk assessments, and most especially incorporating measurable residual disease (MRD) into longitudinal risk assessments. The classification of acute myeloid leukaemia has recently been updated by WHO and the International Consensus Classification (ICC). Recommendations for prognostic stratification, response assessment, and MRD determination have also been updated by the European LeukemiaNet. Treatment options have evolved substantially in the last 5 years for patients with newly diagnosed acute myeloid leukaemia, leading to improved outcomes in intensively treated patients and those more appropriate for non-intensive chemotherapy. More effective targeted treatment options in the relapsed setting are also available, further advancing the treatment armamentarium and improving patient outcomes.

Diagnosis and management of AML in adults: 2022 recommendations from an international expert panel on behalf of the ELN.

The 2010 and 2017 editions of the European LeukemiaNet (ELN) recommendations for diagnosis and management of acute myeloid leukemia (AML) in adults are widely recognized among physicians and investigators. There have been major advances in our understanding of AML, including new knowledge about the molecular pathogenesis of AML, leading to an update of the disease classification, technological progress in genomic diagnostics and assessment of measurable residual disease, and the successful development of new therapeutic agents, such as FLT3, IDH1, IDH2, and BCL2 inhibitors. These advances have prompted this update that includes a revised ELN genetic risk classification, revised response criteria, and treatment recommendations.

Effective therapy for AML with RUNX1 mutation by cotreatment with inhibitors of protein translation and BCL2.

The majority of RUNX1 mutations in acute myeloid leukemia (AML) are missense or deletion-truncation and behave as loss-of-function mutations. Following standard therapy, AML patients expressing mtRUNX1 exhibit inferior clinical outcome than those without mutant RUNX1. Studies presented here demonstrate that as compared with AML cells lacking mtRUNX1, their isogenic counterparts harboring mtRUNX1 display impaired ribosomal biogenesis and differentiation, as well as exhibit reduced levels of wild-type RUNX1, PU.1, and c-Myc. Compared with AML cells with only wild-type RUNX1, AML cells expressing mtRUNX1 were also more sensitive to the protein translation inhibitor homoharringtonine (omacetaxine) and BCL2 inhibitor venetoclax. Homoharringtonine treatment repressed enhancers and their BRD4 occupancy and was associated with reduced levels of c-Myc, c-Myb, MCL1, and Bcl-xL. Consistent with this, cotreatment with omacetaxine and venetoclax or BET inhibitor induced synergistic in vitro lethality in AML expressing mtRUNX1. Compared with each agent alone, cotreatment with omacetaxine and venetoclax or BET inhibitor also displayed improved in vivo anti-AML efficacy, associated with improved survival of immune-depleted mice engrafted with AML cells harboring mtRUNX1. These findings highlight superior efficacy of omacetaxine-based combination therapies for AML harboring mtRUNX1.

Lenalidomide promotes the development of TP53-mutated therapy-related myeloid neoplasms.

There is a growing body of evidence that therapy-related myeloid neoplasms (t-MNs) with driver gene mutations arise in the background of clonal hematopoiesis (CH) under the positive selective pressure of chemo- and radiation therapies. Uncovering the exposure relationships that provide selective advantage to specific CH mutations is critical to understanding the pathogenesis and etiology of t-MNs. In a systematic analysis of 416 patients with t-MN and detailed prior exposure history, we found that TP53 mutations were significantly associated with prior treatment with thalidomide analogs, specifically lenalidomide. We demonstrated experimentally that lenalidomide treatment provides a selective advantage to Trp53-mutant hematopoietic stem and progenitor cells (HSPCs) in vitro and in vivo, the effect of which was specific to Trp53-mutant HSPCs and was not observed in HSPCs with other CH mutations. Because of the differences in CK1α degradation, pomalidomide treatment did not provide an equivalent level of selective advantage to Trp53-mutant HSPCs, providing a biological rationale for its use in patients at high risk for t-MN. These findings highlight the role of lenalidomide treatment in promoting TP53-mutated t-MNs and offer a potential alternative strategy to mitigate the risk of t-MN development.

Genomic profiling for clinical decision making in myeloid neoplasms and acute leukemia.

Myeloid neoplasms and acute leukemias derive from the clonal expansion of hematopoietic cells driven by somatic gene mutations. Although assessment of morphology plays a crucial role in the diagnostic evaluation of patients with these malignancies, genomic characterization has become increasingly important for accurate diagnosis, risk assessment, and therapeutic decision making. Conventional cytogenetics, a comprehensive and unbiased method for assessing chromosomal abnormalities, has been the mainstay of genomic testing over the past several decades and remains relevant today. However, more recent advances in sequencing technology have increased our ability to detect somatic mutations through the use of targeted gene panels, whole-exome sequencing, whole-genome sequencing, and whole-transcriptome sequencing or RNA sequencing. In patients with myeloid neoplasms, whole-genome sequencing represents a potential replacement for both conventional cytogenetic and sequencing approaches, providing rapid and accurate comprehensive genomic profiling. DNA sequencing methods are used not only for detecting somatically acquired gene mutations but also for identifying germline gene mutations associated with inherited predisposition to hematologic neoplasms. The 2022 International Consensus Classification of myeloid neoplasms and acute leukemias makes extensive use of genomic data. The aim of this report is to help physicians and laboratorians implement genomic testing for diagnosis, risk stratification, and clinical decision making and illustrates the potential of genomic profiling for enabling personalized medicine in patients with hematologic neoplasms.