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.

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.

A retrospective study of cladribine and low-dose cytarabine-based regimens for the treatment of chronic myelomonocytic leukemia and secondary acute myeloid leukemia.

BACKGROUND: Patients with higher risk chronic myelomonocytic leukemia (CMML) have limited therapeutic options beyond hydroxyurea and hypomethylating agents (HMAs). Regimens based on a backbone of cladribine (CLAD), low-dose cytarabine (LDAC), and an HMA are effective low-intensity therapies for acute myeloid leukemia (AML). METHODS: The authors conducted a retrospective chart review to evaluate the efficacy of CLAD/LDAC/HMA in CMML and secondary acute myeloid leukemia (sAML) arising from CMML. Responses were evaluated according to the 2006 International Working Group criteria for CMML and the 2017 European LeukemiaNet criteria for AML. The overall survival (OS), leukemia-free survival (LFS), and duration of response were evaluated with the Kaplan-Meier method. Patients were stratified on the basis of prior HMA exposure. RESULTS: The authors identified 21 patients with CMML (eight with HMA-naive CMML and 13 with HMA-failure CMML) and 33 patients with sAML (11 with HMA-naive sAML and 22 with HMA-failure sAML) treated with CLAD/LDAC/HMA-based regimens. The CMML cohort was enriched for high-risk features (proliferative type, elevated blasts, and RAS/MAPK mutations). The overall response rate was 33% in CMML (50% in HMA-naive CMML and 23% in HMA-failure CMML) and 48% in sAML (82% in HMA-naive sAML and 32% in HMA-failure sAML). The median OS was 14.4, 8.8, 42.9, and 2.9 months for HMA-naive CMML, HMA-failure CMML, HMA-naive sAML, and HMA-failure sAML, respectively. The median LFS was 14.4 and 3.9 months for HMA-naive CMML and HMA-failure CMML, respectively. CONCLUSIONS: CLAD/LDAC/HMA-based regimens are effective in a subset of patients with higher risk CMML and sAML arising from CMML who have not previously experienced HMA failure. These findings must be confirmed in prospective studies.

Performance of IPSS-M in patients with myelodysplastic syndrome after hypomethylating agent failure.

Evaluation of IPSS-M and exploratory prognostic model for MDS at the time of HMA failure.

Characteristics and clinical outcomes of patients with myeloid malignancies and DDX41 variants.

DDX41 is the most frequently mutated gene in myeloid neoplasms associated with germline predisposition including myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). We analyzed 3795 patients with myeloid neoplasms and identified 151 (4%) with DDX41 variants and a diagnosis of AML (n = 96), MDS (n = 52), and chronic myelomonocytic leukemia (n = 3). The most frequent DDX41 variants were the somatic variant p.R525H, followed by the germline variants p.M1I and p.D140fs. Most neoplasms had a normal karyotype (59%) and the most frequent co-mutations were TP53 (16%) and ASXL1 (15%). 30% of patients had no concomitant mutations besides DDX41 mutation. Patients with myeloid malignancies and DDX41 variants responded well to therapy, with an overall response rate for patients with treatment naïve AML and MDS of 87% and 84%, respectively. The median overall survival (mOS) of patients with treatment-naïve AML or MDS was 49 and 71 months, respectively. Patients with AML treated with low-intensity regimens including venetoclax had an improved survival (2-year OS 91% vs. 60%, p = .02) and lower cumulative incidence of relapse compared to those treated without venetoclax (10% vs. 56%, p = .03). In the 33% of patients receiving hematopoietic stem cell transplantation, the 2-year OS was 80% and 85% for AML and MDS, respectively.

Invasive mucorales sinusitis in a young patient with Emberger syndrome and newly diagnosed AML: A case report and literature review of invasive fungal infections in GATA2 deficiency.

Germline pathogenic variants (PVs) in the gene encoding the GATA2 transcription factor can result in profound reductions of monocytes, dendritic cells, natural killer cells and B cells. GATA2 PVs are associated with an increased risk of myeloid malignancies and a predisposition to nontuberculous mycobacterial and human papillomavirus infections. Additionally, invasive fungal infections (IFIs) have been reported in individuals with GATA2 PVs, even in the absence of myeloid malignancies. In this report, we present the case of a 40-year-old man with Emberger syndrome (GATA2 mutation, recently diagnosed acute myeloid leukaemia [AML] and history of lymphedema with hearing loss) who developed Mucorales sinusitis while receiving his first course of remission induction chemotherapy. Additionally, we review the literature on all published cases of proven IFIs in patients with GATA2 PVs. Clinicians should be aware that patients with GATA2 PVs could be vulnerable to opportunistic IFIs, even in the absence of AML and antineoplastic therapy. Furthermore, the distinctly unusual occurrence of mucormycosis during the first course of induction chemotherapy for AML in our patient indicates that patients with germline GATA2 PVs receiving induction chemotherapy for AML might be at high risk for early onset of IFIs due to aggressive, opportunistic moulds.

A Phase II Study of Azacitidine, Venetoclax, and Trametinib in Relapsed or Refractory Acute Myeloid Leukemia Harboring RAS Pathway-Activating Mutations.

INTRODUCTION: RAS pathway mutations are common mechanisms of resistance to acute myeloid leukemia (AML) therapies. Trametinib, an oral MEK inhibitor, has been shown to have single-agent activity in relapsed/refractory AML and preclinical synergy with venetoclax. METHODS: We conducted a single-center, open-label, phase 2 trial of the combination of azacitidine, venetoclax, and trametinib in patients with relapsed or refractory AML harboring a RAS pathway-activating mutation. RESULTS: Sixteen patients were treated. The patients were heavily pretreated with a median number of 4 prior therapies; 13 (81%) had received a prior hypomethylating agent (HMA) with venetoclax, and 8 (50%) had undergone prior stem cell transplant. Four patients (25%) responded (CR, n = 1; CRi, n = 1; MLFS, n = 2). Two of the 3 patients (67%) who had not previously received HMA plus venetoclax responded; in contrast, only 2 of the 13 patients (15%) who had previously received HMA plus venetoclax responded. The median OS was 2.4 months, and the 6-month OS rate was 31%. Related grade 3-4 adverse events occurred in 50% of patients, and 50% of patients required a dose adjustment of trametinib. CONCLUSIONS: The combination of azacitidine, venetoclax, and trametinib had only modest activity in patients with relapsed/refractory AML, with a response rate that was similar to previous reports of trametinib monotherapy. Substantial toxicity was observed with this combination. Given the established role of RAS pathway mutations in mediating resistance to AML therapies, future studies of better tolerated, more active inhibitors of this pathway are still needed.

Phase II study of azacitidine with pembrolizumab in patients with intermediate-1 or higher-risk myelodysplastic syndrome.

Programmed cell death protein 1 (PD-1) and PD-ligand 1 (PD-L1) expression is upregulated in cluster of differentiation 34 (CD34)+ bone marrow cells from patients with myelodysplastic syndromes (MDS). Hypomethylating agent (HMA) treatment results in further increased expression of these immune checkpoints. We hypothesised that combining an anti-PD-1 antibody with HMAs may have efficacy in patients with MDS. To test this concept, we designed a phase II trial of the combination of azacitidine and pembrolizumab with two cohorts. In the 17 previously untreated patients, the overall response rate (ORR) was 76%, with a complete response (CR) rate of 18% and median overall survival (mOS) not reached after a median follow-up of 12·8 months. For the HMA-failure cohort (n = 20), the ORR was 25% and CR rate was 5%; with a median follow-up of 6·0 months, the mOS was 5·8 months. The most observed toxicities were pneumonia (32%), arthralgias (24%) and constipation (24%). Immune-related adverse events requiring corticosteroids were required in 43%. Overall, this phase II trial suggests that azacitidine and pembrolizumab is safe with manageable toxicities in patients with higher-risk MDS. This combined therapy may have anti-tumour activity in a subset of patients and merits further studies in the front-line setting.

Myelodysplastic syndromes: 2021 update on diagnosis, risk stratification and management.

DISEASE OVERVIEW: The myelodysplastic syndromes (MDS) are a very heterogeneous group of myeloid disorders characterized by peripheral blood cytopenias and increased risk of transformation to acute myelogenous leukemia (AML). Myelodysplastic syndromes occur more frequently in older males and in individuals with prior exposure to cytotoxic therapy. DIAGNOSIS: Diagnosis of MDS is based on morphological evidence of dysplasia upon visual examination of a bone marrow aspirate and biopsy. Information obtained from additional studies such as karyotype, flow cytometry and molecular genetics is usually complementary and may help refine diagnosis. RISK-STRATIFICATION: Prognosis of patients with MDS can be calculated using a number of scoring systems. In general, all these scoring systems include analysis of peripheral cytopenias, percentage of blasts in the bone marrow and cytogenetic characteristics. The most commonly accepted system is the Revised International Prognostic Scoring System (IPSS-R). Somatic mutations can help define prognosis and therapy. RISK-ADAPTED THERAPY: Therapy is selected based on risk, transfusion needs, percent of bone marrow blasts, cytogenetic and mutational profiles, comorbidities, potential for allogeneic stem cell transplantation (alloSCT) and prior exposure to hypomethylating agents (HMA). Goals of therapy are different in lower-risk patients than in higher-risk individuals and in those with HMA failure. In lower-risk MDS, the goal is to decrease transfusion needs and transformation to higher risk disease or AML, as well as to improve survival. In higher-risk disease, the goal is to prolong survival. In 2020, we witnessed an explosion of new agents and investigational approaches. Current available therapies include growth factor support, lenalidomide, HMAs, intensive chemotherapy and alloSCT. Novel therapeutics approved in 2020 are luspatercept and the oral HMA ASTX727. At the present time, there are no approved interventions for patients with progressive or refractory disease particularly after HMA-based therapy. Options include participation in a clinical trial, cytarabine-based therapy or alloSCT.

Safety and tolerability of lurbinectedin (PM01183) in patients with acute myeloid leukemia and myelodysplastic syndrome.

Trabectedin is an FDA-approved DNA minor groove binder that has activity against translocation-associated sarcomas. Lurbinectedin is a next-generation minor groove binder with preclinical activity against myeloid leukemia cells. A dose-finding phase 1 clinical trial was performed in patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) with further assessment of safety and tolerability. Forty-two patients with relapsed/refractory AML/MDS received lurbinectedin administered as a 1-hour intravenous infusion in a 3 + 3 study design. Two dosing schedules were used: 3.5, 5, 7, or 6 mg on days 1 and 8 or 2, 3, 1, or 1.5 mg for 3 consecutive days on days 1 to 3. Three patients experienced dose-limiting toxicities of rhabdomyolysis (grade 4), hyperbilirubinemia (grade 3), and oral herpes (grade 3) with the day 1 and 8 schedule. Otherwise, adverse events mainly consisted of gastrointestinal manifestations (n = 11), febrile neutropenia/infections (n = 4), pulmonary toxicity (n = 2), and renal failure (n = 2). The most common laboratory abnormalities observed were an increase in creatinine (93%) and anemia, neutropenia, and thrombocytopenia (100%). Overall, 33 of 42 patients (79%) had reduction in blasts in peripheral blood or bone marrow. One patient achieved a partial response and 2 patients a morphologic leukemia-free state. Most (n = 30, 71%) were discontinued due to progressive disease. Early deaths occurred from disease-related causes that were not attributable to lurbinectedin. Four patients with a chromosome 11q21-23 abnormality had significantly greater bone marrow blast reduction than those without such abnormality, with decrease of 31 ± 14% (n = 4) vs 8 ± 8% (n = 16), respectively (P = .04). Overall, lurbinectedin was safe and tolerated using the schedules and dose levels tested. While no sustained remissions were observed, single-agent lurbinectedin was transiently leukemia suppressive for some patients.

Cancer patients with clonal hematopoiesis die from primary malignancy or comorbidities despite higher rates of transformation to myeloid neoplasms.

BACKGROUND: The occurrence of somatic mutations in patients with no evidence of hematological disorders is called clonal hematopoiesis (CH). CH, whose subtypes include CH of indeterminate potential and clonal cytopenia of undetermined significance, has been associated with both hematologic cancers and systemic comorbidities. However, CH's effect on patients, especially those with concomitant malignancies, is not fully understood. METHODS: We performed a retrospective evaluation of all patients with CH at a tertiary cancer center. Patient characteristics, mutational data, and outcomes were collected and analyzed. RESULTS: Of 78 individuals included, 59 (76%) had a history of cancer and 60 (77%) had moderate to severe comorbidity burdens. DNMT3A, TET2, TP53, and ASXL1 were the most common mutations. For the entire cohort, the 2-year overall survival rate was 79% (95% CI: 70, 90), while the median survival was not reached. Of 20 observed deaths, most were related to primary malignancies (n = 7, 35%), comorbidities (n = 4, 20%), or myeloid neoplasms (n = 4, 20%). Twelve patients (15%) experienced transformation to a myeloid neoplasm. According to the clonal hematopoiesis risk score, the 3-year transformation rate was 0% in low-risk, 15% in intermediate-risk (p = 0.098), and 28% in high-risk (p = 0.05) patients. By multivariate analysis, transformation was associated with variant allele frequency ≥0.2 and hemoglobin <10 g/dL. CONCLUSIONS: In a population including mostly cancer patients, CH was associated with comorbidities and myeloid transformation in patients with higher mutational burdens and anemia. Nevertheless, such patients were less likely to die of their myeloid neoplasm than of primary malignancy or comorbidities.

Therapy-related chronic myelomonocytic leukemia does not have the high-risk features of a therapy-related neoplasm.

ABSTRACT: Therapy-related myeloid neoplasms (t-MNs) arise after exposure to cytotoxic therapies and are associated with high-risk genetic features and poor outcomes. We analyzed a cohort of patients with therapy-related chronic myelomonocytic leukemia (tCMML; n = 71) and compared its features to that of de novo CMML (dnCMML; n = 461). Median time from cytotoxic therapy to tCMML diagnosis was 6.5 years. Compared with dnCMML, chromosome-7 abnormalities (4% vs 13%; P = .005) but not complex karyotype (3% vs 7%; P = .15), were more frequent in tCMML. tCMML was characterized by higher TP53 mutation frequency (4% vs 12%; P = .04) and lower NRAS (6% vs 22%, P = .007) and CBL (4% vs 12%, P = .04) mutation frequency. Prior therapy with antimetabolites (odd ratio [OR], 1.22; 95% confidence interval [CI], 1.05-1.42; P = .01) and mitotic inhibitors (OR, 1.24; 95% CI, 1.06-1.44; P = .009) was associated with NF1 and SETBP1 mutations whereas prior mitotic inhibitor therapy was associated with lower TET2 mutation frequency (OR, 0.71; 95% CI, 0.55-0.92; P = .01). Although no differences in median overall survival (OS) were observed among tCMML and dnCMML (34.7 months vs 35.9 months, P = .26), multivariate analysis for OS revealed that prior chemotherapy was associated with increased risk of death (hazard ratio, 1.76; 95% CI, 1.07-2.89; P = .026). Compared with a cohort of therapy-related myelodysplastic syndrome, tCMML had lower TP53 mutation frequency (12% vs 44.4%, P < .001) and less unfavorable outcomes. In summary, tCMML does not exhibit the high-risk features and poor outcomes of t-MNs.

Cytogenetic and Molecular Associations with Outcomes in Higher-Risk Myelodysplastic Syndromes Treated with Hypomethylating Agents plus Venetoclax.

PURPOSE: Hypomethylating agents (HMA) combined with venetoclax are an emerging therapeutic strategy for higher-risk myelodysplastic syndromes (HR-MDS). The cytogenetic and molecular factors associated with outcomes with this combination for HR-MDS are incompletely understood. EXPERIMENTAL DESIGN: We pooled patient data from 3 prospective trials evaluating HMA-venetoclax in HR-MDS to study associations between cytogenetic and molecular factors and overall response rate (ORR), overall survival (OS), and event-free survival (EFS). The Kaplan-Meier method was used to estimate time-to-event endpoints. Univariate and multivariate analyses using logistic regression (for ORR) or the Cox proportional hazards model (for OS and EFS) were used to identify associations between clinical, cytogenetic, and molecular factors and outcomes. RESULTS: A total of 80 patients (52 HMA-naïve, 28 HMA-failure) were included. ORR was 90% in HMA-naïve and 57% in HMA-failure. Median OS was 28.2 and 8.3 months in HMA-naïve and HMA-failure, respectively. Median EFS was 17.9 and 5.5 months in HMA-naïve and HMA-failure, respectively. In addition, 24/52 (46%) of the HMA-naïve and 3/28 (11%) of the HMA-failure patients proceeded to allogeneic stem cell transplantation (SCT). Factors associated with inferior outcomes were prior HMA failure, complex cytogenetics, trisomy 8, TP53 mutations, and RAS pathway mutations. Mutations in RNA splicing, DNA methylation, and ASXL1 appeared favorable. Blast percentage was not predictive of outcomes. CONCLUSIONS: Knowledge of cytogenetic and molecular alterations may help identify which patients with HR-MDS benefit the most from venetoclax.

Azacitidine, Venetoclax, and Gilteritinib in Newly Diagnosed and Relapsed or Refractory FLT3-Mutated AML.

PURPOSE: Azacitidine plus venetoclax is a standard of care for patients with newly diagnosed AML who are unfit for intensive chemotherapy. However, FLT3 mutations are a common mechanism of resistance to this regimen. The addition of gilteritinib, an oral FLT3 inhibitor, to azacitidine and venetoclax may improve outcomes in patients with FLT3-mutated AML. METHODS: This phase I/II study evaluated azacitidine, venetoclax, and gilteritinib in two cohorts: patients with (1) newly diagnosed FLT3-mutated AML who were unfit for intensive chemotherapy or (2) relapsed/refractory FLT3-mutated AML (ClinicalTrials.gov identifier: NCT04140487). The primary end points were the maximum tolerated dose of gilteritinib (phase I) and the combined complete remission (CR)/CR with incomplete hematologic recovery (CRi) rate (phase II). RESULTS: Fifty-two patients were enrolled (frontline [n = 30]; relapsed/refractory [n = 22]). The recommended phase II dose was gilteritinib 80 mg once daily in combination with azacitidine and venetoclax. In the frontline cohort, the median age was 71 years and 73% of patients had an FLT3-internal tandem duplication (ITD) mutation. The CR/CRi rate was 96% (CR, 90%; CRi, 6%). Sixty-five percent of evaluable patients achieved FLT3-ITD measurable residual disease <5 × 10-5 within four cycles. With a median follow-up of 19.3 months, the median relapse-free survival (RFS) and overall survival (OS) have not been reached and the 18-month RFS and OS rates are 71% and 72%, respectively. In the relapsed/refractory cohort, the CR/CRi rate was 27%; nine additional patients (41%) achieved a morphologic leukemia-free state. The most common grade 3 or higher nonhematologic adverse events were infection (62%) and febrile neutropenia (38%), which were more frequent in the relapsed/refractory cohort. CONCLUSION: The combination of azacitidine, venetoclax, and gilteritinib resulted in high rates of CR/CRi, deep FLT3 molecular responses, and encouraging survival in newly diagnosed FLT3-mutated AML. Myelosuppression was manageable with mitigative dosing strategies.

Outcomes of breakthrough COVID-19 infections in patients with hematologic malignancies.

Patients with hematologic malignancies have both an increased risk for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections and higher morbidity/mortality. They have lower seroconversion rates after vaccination, potentially leading to inferior coronavirus disease 2019 (COVID-19) outcomes, despite vaccination. We consequently evaluated the clinical outcomes of COVID-19 infections in 243 vaccinated and 175 unvaccinated patients with hematologic malignancies. Hospitalization rates were lower in the vaccinated group when compared with the unvaccinated group (31.3% vs 52.6%). However, the rates of COVID-19-associated death were similar at 7.0% and 8.6% in vaccinated and unvaccinated patients, respectively. By univariate logistic regression, females, older patients, and individuals with higher modified Charlson Comorbidity Index scores were at a higher risk of death from COVID-19 infections. To account for the nonrandomized nature of COVID-19 vaccination status, a propensity score weighting approach was used. In the final propensity-weighted model, vaccination status was not significantly associated with the risk of death from COVID-19 infections but was associated with the risk of hospitalization. The predicted benefit of vaccination was an absolute decrease in the probability of death and hospitalization from COVID-19 infections by 2.3% and 22.9%, respectively. In conclusion, COVID-19 vaccination status in patients with hematologic malignancies was associated with a decreased risk of hospitalization but not associated with a decreased risk of death from COVID-19 infections in the pre-Omicron era. Protective strategies, in addition to immunization, are warranted in this vulnerable patient population.

MDM2 antagonist improves therapeutic activity of azacitidine in myelodysplastic syndromes and chronic myelomonocytic leukemia.

Failure of hypomethylation agent (HMA) treatments is an important issue in myelodysplastic syndromes (MDS) and chronic myelomonocytic leukemia (CMML). Recent studies indicated that function of wildtype TP53 positively impacts outcome of HMA treatments. We investigated the combination of the HMA azacitidine (AZA) with DS-3032b and DS-5272, novel antagonists of the TP53 negative regulator MDM2, in cellular and animal models of MDS and CMML. In TP53 wildtype myeloid cell line, combinational effects of DS-3032b or DS-5272 with AZA were observed. In Tet2-knockout mouse model of MDS and CMML, DS-5272 and AZA combination ameliorated disease-like phenotype. RNA-Seq analysis in mouse bone marrow hematopoietic stem and progenitors indicated that DS-5272 and AZA combination caused down-regulation of leukemia stem cell marker genes and activation of pathways of TP53 function and stability. These findings demonstrate that combining an MDM2 antagonist with AZA has potential to improve AZA treatment in TP53 wildtype MDS and CMML.

Concurrent Mutations in SF3B1 and PHF6 in Myeloid Neoplasms.

It has been reported that gene mutations in SF3B1 and PHF6 are mutually exclusive. However, this observation has never been rigorously assessed. We report the clinicopathologic and molecular genetic features of 21 cases of myeloid neoplasms with double mutations in SF3B1 and PHF6, including 9 (43%) with myelodysplastic syndrome, 5 (24%) with acute myeloid leukemia, 4 (19%) with myeloproliferative neoplasms, and 3 (14%) with myelodysplastic/myeloproliferative neoplasms. Multilineage dysplasia with ring sideroblasts, increased blasts, and myelofibrosis are common morphologic findings. All cases but one had diploid or non-complex karyotypes. SF3B1 mutations were detected in the first analysis of all the patients. PHF6 mutations occurred either concurrently with SF3B1 mutations or in subsequent follow-up samples and are associated with disease progression and impending death in most cases. Most cases had co-mutations, the most common being ASXL1, RUNX1, TET2, and NRAS. With a median follow-up of 39 months (range, 3-155), 17 (81%) patients died, 3 were in complete remission, and 1 had persistent myelodysplastic syndrome. The median overall survival was 51 months. In summary, concurrent mutations in SF3B1 and PHF6 are rare, but they do exist in a variety of myeloid neoplasms, with roles as early initiating events and in disease progression, respectively.

Transcriptomic Signatures of Hypomethylating Agent Failure in Myelodysplastic Syndromes and Chronic Myelomonocytic Leukemia.

Hypomethylating agents (HMAs) are the standard of care for myelodysplastic syndromes (MDS) and chronic myelomonocytic leukemia (CMML). HMA treatment failure is a major clinical problem and its mechanisms are poorly characterized. We performed RNA sequencing in CD34+ bone marrow stem hematopoietic stem and progenitor cells (BM-HSPCs) from 51 patients with CMML and MDS before HMA treatment and compared transcriptomic signatures between responders and nonresponders. We observed very few genes with significant differential expression in HMA non-responders versus responders, and the commonly altered genes in non-responders to both azacitidine (AZA) and decitabine (DAC) treatments were immunoglobulin genes. Gene set analysis identified 78 biological pathways commonly altered in non-responders to both treatments. Among these, we determined that the γ-aminobutyric acid (GABA) receptor signaling significantly affected hematopoiesis in both human BM-HSPCs and mice, indicating that the transcriptomic signatures identified here could serve as candidate biomarkers and therapeutic targets for HMA failure in MDS and CMML.