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32 result(s) for "Marzac, Christophe"
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Genetic hierarchy and temporal variegation in the clonal history of acute myeloid leukaemia
In acute myeloid leukaemia (AML) initiating pre-leukaemic lesions can be identified through three major hallmarks: their early occurrence in the clone, their persistence at relapse and their ability to initiate multilineage haematopoietic repopulation and leukaemia in vivo . Here we analyse the clonal composition of a series of AML through these characteristics. We find that not only DNMT3A mutations, but also TET2 , ASXL1 mutations, core-binding factor and MLL translocations, as well as del(20q) mostly fulfil these criteria. When not eradicated by AML treatments, pre-leukaemic cells with these lesions can re-initiate the leukaemic process at various stages until relapse, with a time-dependent increase in clonal variegation. Based on the nature, order and association of lesions, we delineate recurrent genetic hierarchies of AML. Our data indicate that first lesions, variegation and treatment selection pressure govern the expansion and adaptive behaviour of the malignant clone, shaping AML in a time-dependent manner. Pre-leukaemic clones, together with the propensity to cause disease in mice, are characterized by appearing early in myeloid leukaemia and being found at relapse. Here, the authors identify clones in human samples and find that they are characterized by hierarchically organized genetic lesions, which can be used to track evolution of the disease.
A Web-Based Delphi Study for Eliciting Helpful Criteria in the Positive Diagnosis of Hemophagocytic Syndrome in Adult Patients
The diagnosis of the reactive form of hemophagocytic syndrome in adults remains particularly difficult since none of the clinical or laboratory manifestations are specific. We undertook a study in order to elicit which features constitute helpful criteria for a positive diagnosis. In this Delphi study, the features investigated in the questionnaire and the experts invited to participate in the survey were issued from a bibliographic search. The questionnaire was iteratively proposed to experts via a web-based application with a feedback of the results observed at the preceding Delphi round. Experts were asked to label each investigated criterion in one of the following categories: absolutely required, important, of minor interest, or not assessable in the routine practice environment. A positive consensus was a priori defined as at least 75% answers observed in the categories absolutely required and important. The questionnaire investigated 26 criteria and 24 experts originating from 13 countries participated in the second and final Delphi round. A positive consensus was reached for the nine following criteria: unilineage cytopenia, bicytopenia, pancytopenia, presence of hemophagocytosis pictures on a bone marrow aspirate or on a tissue biopsy, high ferritin level, fever, organomegaly, presence of a predisposing underlying disease, and high level of lactate dehydrogenase. A negative consensus was reached for 13 criteria, and an absence of consensus was observed for 4 criteria. The study constitutes the first initiative to date for defining international guidelines devoted to the positive diagnosis of the reactive form of hemophagocytic syndrome.
Reduced venetoclax exposure to 7 days vs standard exposure with hypomethylating agents in newly diagnosed AML patients
Hypomethylating agent (HMA) plus venetoclax (VEN) regimens are standard of care in patients with acute myeloid leukemia (AML) ineligible for intensive chemotherapy. While the VEN label recommends continuous 28-day cycles, shortened VEN durations may induce similar response rates and improve tolerability. It is unknown how a VEN exposure reduced to 7 days during cycles compares to standard HMA + VEN. We retrospectively compared newly diagnosed AML patients treated with azacitidine (AZA) x 7 days plus VEN x 7 days (“7 + 7” regimen) from the first cycle ( n  = 82) vs patients treated with standard dose HMA + VEN (std-HMA/VEN) ( n  = 166). Composite complete remission rate was similar between cohorts (72% vs 72%; p  = 0.95) and a median number of cycles to best response was 2 with “7 + 7” vs 1 with std-HMA/VEN ( p  = 0.03). Concerning toxicity, platelet transfusion rates during cycle 1 as well as early mortality at 8-weeks (6% vs 16%; p  = 0.03) were lower in “7 + 7” cohort. Finally, the median OS was 11.2 months (2-year 28%) with “7 + 7” vs 10.3 months (2-year 34%) with “std-HMA/VEN” ( p  = 0.75). In summary, acknowledging limitations of a retrospective comparison, a shortened course of VEN used for 7 days every 28 days resulted in similar response rates and survival when compared to standard VEN exposure.
Molecular aspects of myeloproliferative neoplasms
During these past 5 years several studies have provided major genetic insights into the pathogenesis of the so-called classical myeloproliferative neoplasms (MPNs): polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). The discovery of the JAK2V617F mutation first, then of the JAK2 exon 12 and MPLW515 mutations, have modified the understanding of these diseases, their diagnosis, and management. Now it is established that almost 100% of PV patients present a JAK2 mutation. Nearly 60% of ET patients and 50% of patients with PMF have the JAK2V617F mutation. The MPLW515 mutations are also present in a small proportion of ET and PMF patients. These mutations are oncogenic events that cause these disorders; however, they do not explain the heterogeneity of the entities in which they occur. Genetic defects have not been yet identified in around 40% of ET and PMF. There are likely additional somatic genetic factors important for the MPN phenotype like the recently described TET2 , ASXL1 , and CBL mutations. Moreover, polymorphisms in the JAK2 gene have been recently described as associated with MPN. Additional studies of large cohorts are required to dissect the genetic events in MPNs and the mechanisms of these oncogenic cooperations.
Different impact of calreticulin mutations on human hematopoiesis in myeloproliferative neoplasms
Mutations of calreticulin (CALRm) define a subtype of myeloproliferative neoplasms (MPN). We studied the biological and genetic features of CALR-mutated essential thrombocythemia and myelofibrosis patients. In most cases, CALRm were found in granulocytes, monocytes, B and NK cells, but also in T cells. However, the type 1 CALRm spreads more easily than the type 2 CALRm in lymphoid cells. The CALRm were also associated with an early clonal dominance at the level of hematopoietic stem and progenitor cells (HSPC) with no significant increase during granulo/monocytic differentiation in most cases. Moreover, we found that half of type 2 CALRm patients harbors some homozygous progenitors. Those patients were associated with a higher clonal dominance during granulo/monocytic differentiation than patients with only heterozygous type 2 CALRm progenitors. When associated mutations were present, CALRm were the first genetic event suggesting that they are both the initiating and phenotypic event. In blood, type 1 CALRm led to a greater increased number of all types of progenitors compared with the type 2 CALRm. However, both types of CALRm induced an increase in megakaryocytic progenitors associated with a ruxolitinib-sensitive independent growth and with a mild constitutive signaling in megakaryocytes. At the transcriptional level, type 1 CALRm seems to deregulate more pathways than the type 2 CALRm in megakaryocytes. Altogether, our results show that CALRm modify both the HSPC and megakaryocyte biology with a stronger effect for type 1 than for type 2 CALRm.
Olutasidenib for mutated IDH1 acute myeloid leukemia: final five-year results from the phase 2 pivotal cohort
Background Olutasidenib is an oral, selective inhibitor of mutant isocitrate dehydrogenase 1 (mIDH1), FDA-approved for relapsed/refractory (R/R) acute myeloid leukemia (AML) based on a registrational, phase 2, open-label, multicenter trial. Methods Results from the pre-planned interim analysis were previously published (data cut-off [DCO]: June 2021). In this final-follow up analysis, we report an additional 2 years of efficacy and safety data (DCO: June 2023). Results At study completion, the overall population included 153 patients (median age, 71 years); 66% had received ≥ 2 prior treatment regimens, and 39% with a hypomethylating agent. Among the 147 efficacy-evaluable patients, 51 achieved complete remission (CR) or CR with partial hematologic recovery (CRh), resulting in a CR/CRh rate of 35% ( P  < 0.001; 95% CI, 27–43), with 32% of responders achieving CR. The median time to CR/CRh was 1.9 months (range, 0.9–5.6 months). Among responders, 33% achieved CR/CRh within 2–4 months and 12% required ≥ 4 months. The overall response rate (ORR) was 48% ( n  = 71; 95% CI, 40–56.7). Median duration of CR/CRh was 25.3 months (95% CI, 13.5–not reached), and median overall survival (OS) was 11.5 months (95% CI, 8.3–15.5). Patients with 1–2 prior regimens had a higher CR/CRh rate (41%) and longer median OS (13 months) than those with ≥ 3 prior regimens (CR/CRh: 24%; median OS: 8.9 months). CR/CRh rates were higher among patients with R132C (42%) and R132L/G/S mutations (33%) compared with those harboring R132H mutations (17%). Response rates decreased with increasing numbers of co-mutations. Few new adverse events (AEs) and no treatment discontinuations due to AEs occurred beyond Year 3. Conclusion These 5-year data support the durable efficacy and manageable safety profile of olutasidenib in R/R m IDH1 AML, including heavily pretreated patients. Findings highlight the potential role of olutasidenib in earlier lines of treatment, and support sustaining therapy for at least 6 months to allow for a clinical response. Further research is warranted to optimize treatment sequencing and patient selection. Trial registration NCT02719574.
Higher risk profile among patients with TET2-mutated giant cell arteritis: a cluster analysis
ObjectiveWe aimed to assess the prevalence of clonal haematopoiesis (CH) in patients with giant cell arteritis (GCA) compared with controls and individuals with other autoimmune diseases (AIDs) and to identify high-risk clinical/genetic profiles that could influence disease outcomes.MethodsIn a prospective observational study at three hospitals, we included 49 patients diagnosed with GCA, 48 patients with other AIDs and 27 control participants. We used next-generation sequencing to detect clonal haematopoiesis (CH) among them.ResultsCH was detected in 55.1% of patients with GCA, 59.3% of controls and 18.8% of patients with other AIDs. The most commonly mutated genes in GCA and control groups were DNMT3A and TET2. No significant differences in CH prevalence were found between patients with GCA and controls or other AID when adjusted for age and sex. Cluster analysis revealed two distinct groups within the patients with GCA, one of which displayed a higher prevalence of TET2 and JAK2 variants, and was associated with worse prognosis.ConclusionsCH is prevalent among patients with GCA but does not differ significantly from controls or other autoimmune conditions. However, specific genetic profiles, particularly mutations in TET2 and JAK2, are associated with a higher risk cluster within the GCA cohort. This observation highlights the interest of detecting CH in patients with GCA in both routine practice and clinical trials for better risk stratification. Further prospective studies are needed to determine if management tailored to the genetic profile would improve outcomes.