UNASSIGNED: Chronic myelomonocytic leukemia (CMML) and myelodysplastic syndromes (MDS) with ring sideroblasts (RS) or SF3B1 mutation (MDS-RS/SF3B1) differ in many clinical features, but share others, such as anemia. RS and SF3B1 mutation can also be found in CMML.
UNASSIGNED: We compared CMML with and without RS/SF3B1 and MDS-RS/SF3B1 considering the criteria established by the 2022 World Health Organization classification.
UNASSIGNED: A total of 815 patients were included (CMML, n=319, CMML-RS/SF3B1, n=172 and MDS-RS/SF3B1, n=324). The percentage of RS was ≥15% in almost all CMML-RS/SF3B1 patients (169, 98.3%) and most (125, 72.7%) showed peripheral blood monocyte counts between 0.5 and 0.9 x109/L and low risk prognostic categories. CMML-RS/SF3B1 differed significantly from classical CMML in the main clinical characteristics, whereas it resembled MDS-RS/SF3B1. At a molecular level, CMML and CMML-RS/SF3B1 had a significantly higher frequency of mutations in TET2 (mostly multi-hit) and ASXL1 (p=0.013) and CMML had a significantly lower frequency of DNMT3A and SF3B1 mutations compared to CMML/MDS-RS/SF3B1. Differences in the median overall survival among the three groups were statistically significant: 6.75 years (95% confidence interval [CI] 5.41-8.09) for CMML-RS/SF3B1 vs. 3.17 years (95% CI 2.56-3.79) for CMML vs. 16.47 years (NA) for MDS-RS/SF3B1, p<0.001. Regarding patients with CMML and MDS, both with SF3B1 mutation, survival did not significantly differ. CMML had a higher risk of transformation to acute myeloid leukemia (24% at 8 years, 95%CI 19%-30%).
UNASSIGNED: CMML-RS/SF3B1 mutation resembles MDS-RS/SF3B1 in terms of phenotype and clearly differs from CMML. The presence of ≥15% RS and/or SF3B1 in CMML is associated with a low monocyte count. SF3B1 mutation clearly improves the prognosis of CMML.

RAS pathway mutations, which are present in 30% of patients with chronic myelomonocytic leukemia (CMML) at diagnosis, confer a high risk of resistance to and progression after hypomethylating agent (HMA) therapy, the current standard of care for the disease. Here, using single-cell, multi-omics technologies, we seek to dissect the biological mechanisms underlying the initiation and progression of RAS pathway-mutated CMML. We identify that RAS pathway mutations induce transcriptional reprogramming of hematopoietic stem and progenitor cells (HSPCs) and downstream monocytic populations in response to cell-intrinsic and -extrinsic inflammatory signaling that also impair the functions of immune cells. HSPCs expand at disease progression after therapy with HMA or the BCL2 inhibitor venetoclax and rely on the NF-κB pathway effector MCL1 to maintain survival. Our study has implications for the development of therapies to improve the survival of patients with RAS pathway-mutated CMML.

Chronic myelomonocytic leukaemia (CMML) is a rare haematological disorder characterized by monocytosis and dysplastic changes in myeloid cell lineages. Accurate risk stratification is essential for guiding treatment decisions and assessing prognosis. This study aimed to validate the Artificial Intelligence Prognostic Scoring System for Myelodysplastic Syndromes (AIPSS-MDS) in CMML and to assess its performance compared with traditional scores using data from a Spanish registry (n = 1343) and a Taiwanese hospital (n = 75). In the Spanish cohort, the AIPSS-MDS accurately predicted overall survival (OS) and leukaemia-free survival (LFS), outperforming the Revised-IPSS score. Similarly, in the Taiwanese cohort, the AIPSS-MDS demonstrated accurate predictions for OS and LFS, showing superiority over the IPSS score and performing better than the CPSS and molecular CPSS scores in differentiating patient outcomes. The consistent performance of the AIPSS-MDS across both cohorts highlights its generalizability. Its adoption as a valuable tool for personalized treatment decision-making in CMML enables clinicians to identify high-risk patients who may benefit from different therapeutic interventions. Future studies should explore the integration of genetic information into the AIPSS-MDS to further refine risk stratification in CMML and improve patient outcomes.

Myeloid neoplasms and acute leukemias include different entities that have been recently re-classified taking into account molecular and clinicopathological features. The myelodysplastic syndrome/myeloproliferative neoplasm (MDS/MPN) category comprises a heterogeneous group of hybrid neoplastic myeloid diseases characterized by the co-occurrence of clinical and pathological features of both myelodysplastic and myeloproliferative neoplasms. The most frequent entity in this category is chronic myelomonocytic leukemia (CMML) which is, after acute myeloid leukemia (AML), the main myeloid disorder prone to develop cutaneous manifestations. Skin lesions associated with myelodysplastic and myeloproliferative neoplasms include a broad clinical, histopathological and molecular spectrum of lesions, poorly understood and without a clear-cut classification in the current medical literature. The aim of this review is to describe and classify the main clinical, histopathological and molecular patterns of cutaneous lesions in the setting of MDS/MPN in order to improve the diagnostic skills of the dermatologists, hematologists and pathologists who deal with these patients.

Chronic myelomonocytic leukemia (CMML) is frequently associated with mutations in the rat sarcoma gene (RAS), leading to worse prognosis. RAS mutations result in active RAS-GTP proteins, favoring myeloid cell proliferation and survival and inducing the NLRP3 inflammasome together with the apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), which promote caspase-1 activation and interleukin (IL)-1β release. Here, we report, in a cohort of CMML patients with mutations in KRAS, a constitutive activation of the NLRP3 inflammasome in monocytes, evidenced by ASC oligomerization and IL-1β release, as well as a specific inflammatory cytokine signature. Treatment of a CMML patient with a KRASG12D mutation using the IL-1 receptor blocker anakinra inhibits NLRP3 inflammasome activation, reduces monocyte count, and improves the patient\'s clinical status, enabling a stem cell transplant. This reveals a basal inflammasome activation in RAS-mutated CMML patients and suggests potential therapeutic applications of NLRP3 and IL-1 blockers.

Recently modified diagnostic criteria for chronic myelomonocytic leukaemia (CMML) have lowered the cut-off for absolute monocytosis. In the largest series to date, we have analysed 313 CMML patients, including 104 with oligomonocytic (OM)-CMML. Five-year survival was longer for OM-CMML than for other patients (p < 0.001). Multivariate analysis identified OM-CMML as a favourable prognostic factor (HR 0.58; p = 0.002). The 5-year cumulative incidence of progression to classical CMML was 47%. Older age and transfusion dependence were adverse prognostic factors for OM-CMML. Our results support the inclusion of OM-CMML in the CMML category as a subtype with superior outcomes.

Failure after hypomethylating agents (HMAs) is associated with dismal outcomes in higher risk myelodysplastic syndromes (HR-MDS) or chronic myelomonocytic leukaemia (CMML). We aimed to evaluate the safety and preliminary activity of lower doses of CPX-351, a liposomal encapsulation of cytarabine and daunorubicin, in a single-centre, phase 1/2 study for patients with HR-MDS or CMML after HMA failure. Four doses of CPX-351 (10, 25, 50 and 75 units/m2 ) administered on Days 1, 3 and 5 of induction and Days 1 and 3 of consolidation were evaluated. Between June 2019 and June 2023, 25 patients were enrolled (phase 1: n = 15; phase 2: n = 10) including 19 (76%) with HR-MDS and 6 (24%) with CMML. Most common grade 3-4 non-haematological treatment-emergent adverse events were febrile neutropenia (n = 12, 48%) and lung infection (n = 5, 20%). Three patients (age >75) experienced cardiac toxicity at the 75 units/m2 dose. Further enrolment continued at 50 units/m2 . Four- and 8-week mortality were 0% and 8% respectively. The overall response rate was 56% with median relapse-free and overall survivals of 9.2 (95% CI 3.2-15.1 months) and 8.7 months (95% CI 1.8-15.6 months) respectively. These data suggest that lower doses of CPX-351 are safe. Further studies are needed to evaluate its activity.

Chronic myelomonocytic leukemia is a myeloid stem cell disease characterized by an abnormal production and accumulation of monocytic cells in association with other signs of myeloproliferation. Extramedullary manifestations of CMML are common and can affect the spleen, liver skin, and lymph nodes. However, otologic manifestations are extremely rare and could have occurred from either direct leukemic infiltration, hemorrhage of the cochlea, labyrinth, leukostasis, or infection. There is no standard treatment protocol for sensorineural hearing loss in CMML patients. More research is needed to improve the understanding of the pathogenesis of this condition, in order to provide better treatment options.

Chronic myelomonocytic leukaemia (CMML) is a haematological disorder with high risk of transformation to acute myeloid leukaemia (AML). To characterize the phenotypic and genomic patterns of CMML progression, we evaluated a cohort of 189 patients with AML evolving from CMML. We found that transformation occurs through distinct trajectories characterized by genomic profiles and clonal evolution: monocytic (Mo-AML, 53%), immature myeloid (My-AML, 43%) or erythroid (Ery-AML, 2%). Mo-AML, characterized by expansion of monoblasts and promonocytes (low CD34, CD117 expression; high CD14, CD33, CD56 and CD64 expression), were defined by SRSF2, TET2 and RAS pathway mutation co-dominance and were more likely to evolve from SRSF2-TET2 co-mutant CMML through emergence/expansion of RAS pathway mutant clones. Conversely, My-AML, characterized by expansion of immature myeloid blasts (high frequency of CD34, CD38, CD117; low frequency of CD14, CD64 and CD56 expression) were less likely to exhibit SRSF2-TET2 co-mutations or RAS pathway mutations and had higher frequency of CEBPA mutations. Ery-AML was defined by complex karyotypes and TP53 mutations. A trend towards improved OS and EFS with hypomethylating agent-venetoclax combination was observed in My-AML, but not Mo-AML. These findings define distinct progression of CMML and set the basis for future studies evaluating the role of phenotype-specific therapeutics.

Myelodysplastic/myeloproliferative neoplasms (MDS/MPN) are hematological disorders characterized by both proliferative and dysplastic features. According to the 2022 International Consensus Classification (ICC), MDS/MPN consists of clonal monocytosis of undetermined significance (CMUS), chronic myelomonocytic leukemia (CMML), atypical chronic myeloid leukemia (aCML), MDS/MPN with SF3B1 mutation (MDS/MPN-T-SF3B1), MDS/MPN with ring sideroblasts and thrombocytosis not otherwise specified (MDS/MPN-RS-T-NOS), and MDS/MPN-NOS. These disorders exhibit a diverse range of genetic alterations involving various transcription factors (e.g., RUNX1), signaling molecules (e.g., NRAS, JAK2), splicing factors (e.g., SF3B, SRSF2), and epigenetic regulators (e.g., TET2, ASXL1, DNMT3A), as well as specific cytogenetic abnormalities (e.g., 8 trisomies, 7 deletions/monosomies). Clinical studies exploring therapeutic options for higher-risk MDS/MPN overlap syndromes mostly involve hypomethylating agents, but other treatments such as lenalidomide and targeted agents such as JAK inhibitors and inhibitors targeting PARP, histone deacetylases, and the Ras pathway are under investigation. While these treatment modalities can provide partial disease control, allogeneic bone marrow transplantation (allo-BMT) is the only potentially curative option for patients. Important prognostic factors correlating with outcomes after allo-BMT include comorbidities, splenomegaly, karyotype alterations, and the bone marrow blasts percentage at the time of transplantation. Future research is imperative to optimizing therapeutic strategies and enhancing patient outcomes in MDS/MPN neoplasms. In this review, we summarize MDS/MPN diagnostic criteria, biology, and current and future treatment options, including bone marrow transplantation.