Adult Low-Hypodiploid Acute Lymphoblastic Leukemia Emerges from Preleukemic TP53-Mutant Clonal Hematopoiesis

UNLABELLED Low hypodiploidy defines a rare subtype of B-cell acute lymphoblastic leukemia (B-ALL) with a dismal outcome. To investigate the genomic basis of low-hypodiploid ALL (LH-ALL) in adults, we analyzed copy-number aberrations, loss of heterozygosity, mutations, and cytogenetics data in a prospective cohort of Philadelphia (Ph)-negative B-ALL patients (n = 591, ages 18-84 years), allowing us to identify 80 LH-ALL cases (14%). Genomic analysis was critical for evidencing low hypodiploidy in many cases missed by cytogenetics. The proportion of LH-ALL within Ph-negative B-ALL dramatically increased with age, from 3% in the youngest patients (under 40 years old) to 32% in the oldest (over 55 years old). Somatic TP53 biallelic inactivation was the hallmark of adult LH-ALL, present in virtually all cases (98%). Strikingly, we detected TP53 mutations in posttreatment remission samples in 34% of patients. Single-cell proteogenomics of diagnosis and remission bone marrow samples evidenced a preleukemic, multilineage, TP53-mutant clone, reminiscent of age-related clonal hematopoiesis. SIGNIFICANCE We show that low-hypodiploid ALL is a frequent entity within B-ALL in older adults, relying on somatic TP53 biallelic alteration. Our study unveils a link between aging and low-hypodiploid ALL, with TP53-mutant clonal hematopoiesis representing a preleukemic reservoir that can give rise to aneuploidy and B-ALL. See related commentary by Saiki and Ogawa, p. 102. This article is highlighted in the In This Issue feature, p. 101

A Phase 2 Study of Coltuximab Ravtansine (SAR3419) Monotherapy in Patients with Relapsed or Refractory Acute Lymphoblastic Leukemia (ALL)

International audienceBackground Long-term disease-free survival in adult patients with acute lymphoblastic leukemia (ALL) remains unsatisfactory, and treatment options are limited for those patients who relapse or fail to respond following initial therapy. We conducted a dose-escalation/expansion phase 2, multicenter, single-arm study to determine the optimal dose of coltuximab ravtansine (SAR3419), an anti-CD19 antibody-drug conjugate, in this setting. Patients and Methods The dose-escalation part of the study determined the selected dose of coltuximab ravtansine for evaluation of efficacy and safety in the dose-expansion phase. Patients received coltuximab ravtansine induction therapy (up to 8 weekly doses); responding patients were eligible for maintenance therapy (biweekly administrations for up to 24 weeks). Three dose levels of coltuximab ravtansine were examined: 55, 70, and 90 mg/m2. The primary endpoint was objective response rate (ORR). Secondary endpoints included duration of response (DOR) and safety. Results A total of 36 patients were treated: 19 during dose escalation; 17 during dose expansion. One dose-limiting toxicity was observed at 90 mg/m2 (grade 3 peripheral motor neuropathy), and therefore 70 mg/m2 was selected for the dose-expansion phase. Five patients discontinued therapy due to adverse events (AEs). The most common AEs were pyrexia, diarrhea, and nausea. Of 17 evaluable patients treated at the selected dose, 4 responded (estimated ORR using Bayesian methodology: 25.47% [80% confidence interval: 14.18-39.6%]); DOR was 1.94 (range: 1-5.6) months. Based on these results, the study was prematurely discontinued. Conclusions Coltuximab ravtansine is well tolerated but is associated with a low clinical response rate in patients with relapsed/refractory AL

Apport de l'imatinib mesylate dans le traitement de la leucémie myéloïde chronique en phase chronique

BORDEAUX2-BU Santé (330632101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Reproduction and offspring defects after exposure to PAHs mixtures.

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Reproduction and offspring defects after exposure to PAHs mixtures.

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Unsupervised Flow Cytometry Analysis Allows for an Accurate Identification of Minimal Residual Disease Assessment in Acute Myeloid Leukemia

The assessment of minimal residual disease (MRD) is increasingly considered to monitor response to therapy in hematological malignancies. In acute myeloblastic leukemia (AML), molecular MRD (mMRD) is possible for about half the patients while multiparameter flow cytometry (MFC) is more broadly available. However, MFC analysis strategies are highly operator-dependent. Recently, new tools have been designed for unsupervised MFC analysis, segregating cell-clusters with the same immunophenotypic characteristics. Here, the Flow-Self-Organizing-Maps (FlowSOM) tool was applied to assess MFC-MRD in 96 bone marrow (BM) follow-up (FU) time-points from 40 AML patients with available mMRD. A reference FlowSOM display was built from 19 healthy/normal BM samples (NBM), then simultaneously compared to the patient’s diagnosis and FU samples at each time-point. MRD clusters were characterized individually in terms of cell numbers and immunophenotype. This strategy disclosed subclones with varying immunophenotype within single diagnosis and FU samples including populations absent from NBM. Detectable MRD was as low as 0.09% in MFC and 0.051% for mMRD. The concordance between mMRD and MFC-MRD was 80.2%. MFC yielded 85% specificity and 69% sensitivity compared to mMRD. Unsupervised MFC is shown here to allow for an easy and robust assessment of MRD, applicable also to AML patients without molecular markers

Monitoring of asparagine depletion and anti-L-asparaginase antibodies in adult acute lymphoblastic leukemia treated in the pediatric-inspired GRAALL-2005 trial

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