No abstract

Somatic mutations contribute to the heterogeneous prognosis of chronic myelomonocytic leukemia (CMML). Hypomethylating agents (HMAs) are active in CMML, but analyses of small series failed to identify mutations predicting response or survival. We analyzed a retrospective multi-center cohort of 174 CMML patients treated with a median of 7 cycles of azacitidine (n = 68) or decitabine (n = 106). Sequencing data before treatment initiation were available for all patients, from Sanger (n = 68) or next generation (n = 106) sequencing. Overall response rate (ORR) was 52%, including complete response (CR) in 28 patients (17%). In multivariate analysis, ASXL1 mutations predicted a lower ORR (Odds Ratio [OR] = 0.85, p = 0.037), whereas TET2mut/ASXL1wt genotype predicted a higher CR rate (OR = 1.18, p = 0.011) independently of clinical parameters. With a median follow-up of 36.7 months, overall survival (OS) was 23.0 months. In multivariate analysis, RUNX1mut (Hazard Ratio [HR] = 2.00, p = .011), CBLmut (HR = 1.90, p = 0.03) genotypes and higher WBC (log10(WBC) HR = 2.30, p = .005) independently predicted worse OS while the TET2mut/ASXL1wt predicted better OS (HR = 0.60, p = 0.05). CMML-specific scores CPSS and GFM had limited predictive power. Our results stress the need for robust biomarkers of HMA activity in CMML and for novel treatment strategies in patients with myeloproliferative features and RUNX1 mutations.

DDX41 germline mutations (DDX41MutGL) are the most common genetic predisposition to myelodysplastic syndrome and acute myeloid leukemia (AML). Recent reports suggest that DDX41MutGL myeloid malignancies could be considered as a distinct entity, even if their specific presentation and outcome remain to be defined. We described here the clinical and biological features of 191 patients with DDX41MutGL AML. Baseline characteristics and outcome of 86 of them, treated with intensive chemotherapy in 5 prospective ALFA/FILO trials were compared with those of 1604 DDX41 wild-type (DDX41WT) AML patients, representing a prevalence of 5%. DDX41MutGL AML patients were mostly males (75%) in their seventh decade, with low leukocyte count (median, 2x109/L), low bone marrow blast infiltration (median, 33%), normal cytogenetics (75%) and few additional somatic mutations (median, 2). A second somatic DDX41 mutation (DDX41MutSom) was found in 82% of patients and clonal architecture inference suggested that it could be the main driver for AML progression. DDX41MutGL patients displayed higher complete remission (CR) rates (94% vs. 69%, p<0.0001) and longer restricted mean overall survival (OS) censored at hematopoietic stem cell transplantation (HSCT) than ELN-2017 intermediate/adverse (Int/Adv) DDX41WT patients (5-year ΔRMST of 13.6 months, p < 0.001). Relapse rates censored at HSCT were lower at 1 year in DDX41MutGL patients (15% vs. 44%) but later increased to join that of Int/Adv DDX41WT patients at 3 years (82% vs 75%). HSCT in first CR was associated with prolonged relapse-free survival (RFS; HR, 0.43 [95%CI, 0.21-0.88]; p = 0.02) but not with longer OS (HR=0.77 [95%CI, 0.35-1.68], p=0.5).