Ludovic Lhermitte

Toward a NOTCH1/FBXW7/RAS/PTEN–Based Oncogenetic Risk Classification of Adult T-Cell Acute Lymphoblastic Leukemia: A Group for Research in Adult Acute Lymphoblastic Leukemia Study

PURPOSE The Group for Research in Adult Acute Lymphoblastic Leukemia (GRAALL) recently reported a significantly better outcome in T-cell acute lymphoblastic leukemia (T-ALL) harboring NOTCH1 and/or FBXW7 (N/F) mutations compared with unmutated T-ALL. Despite this, one third of patients with N/F-mutated T-ALL experienced relapse. PATIENTS AND METHODS In a series of 212 adult T-ALLs included in the multicenter randomized GRAALL-2003 and -2005 trials, we searched for additional N/K-RAS mutations and PTEN defects (mutations and gene deletion). RESULTS N/F mutations were identified in 143 (67%) of 212 patients, and lack of N/F mutation was confirmed to be associated with a poor prognosis. K-RAS, N-RAS, and PTEN mutations/deletions were identified in three (1.6%) of 191, 17 (8.9%) of 191, and 21 (12%) of 175 patients, respectively. The favorable prognostic significance of N/F mutations was restricted to patients without RAS/PTEN abnormalities. These observations led us to propose a new T-ALL oncogenetic classifier defining low-risk patients as those with N/F mutation but no RAS/PTEN mutation (97 of 189 patients; 51%) and all other patients (49%; including 13% with N/F and RAS/PTEN mutations) as high-risk patients. In multivariable analysis, this oncogenetic classifier remained the only significant prognostic covariate (event-free survival: hazard ratio [HR], 3.2; 95% CI, 1.9 to 5.15; P < .001; and overall survival: HR, 3.2; 95% CI, 1.9 to 5.6; P < .001). CONCLUSION These data demonstrate that the presence of N/F mutations in the absence of RAS or PTEN abnormalities predicts good outcome in almost 50% of adult T-ALL. Conversely, the absence of N/F or presence of RAS/PTEN alterations identifies the remaining cohort of patients with poor prognosis.

Mast cell leukemia

Mast cell leukemia (MCL) is a very rare form of aggressive systemic mastocytosis accounting for < 1% of all mastocytosis. It may appear de novo or secondary to previous mastocytosis and shares more clinicopathologic aspects with systemic mastocytosis than with acute myeloid leukemia. Symptoms of mast cell activation-involvement of the liver, spleen, peritoneum, bones, and marrow-are frequent. Diagnosis is based on the presence of ≥ 20% atypical mast cells in the marrow or ≥ 10% in the blood; however, an aleukemic variant is frequently encountered in which the number of circulating mast cells is < 10%. The common phenotypic features of pathologic mast cells encountered in most forms of mastocytosis are unreliable in MCL. Unexpectedly, non-KIT D816V mutations are frequent and therefore, complete gene sequencing is necessary. Therapy usually fails and the median survival time is < 6 months. The role of combination therapies and bone marrow transplantation needs further investigation.

Amazonia!: An Online Resource to Google and Visualize Public Human whole Genome Expression Data

Available transcriptome data accumulate in public repositories, individual web pages or as various supplemen- tal data, but these published data cannot be routinely accessed. We have developed the web based tool Amazonia! to over- come this hurdle and provide the possibility to query and to visualize the expression of a given gene in representative and selected human transcriptome datasets. This expression atlas provides expression bar plots for single genes, across sam- ples selected from a wide range of normal tissues and malignancies, including pluripotent stem cells. When produced by the same platform type, datasets were renormalized and combined in order to generate series of several hundreds samples. Samples types are colored and ordered, and grouped in thematic pages for ease of navigation. We also integrated gene lists provided by original publications describing these microarray data, allowing the scientific community to challenge the expression of genes in datasets other than those for which they were initially published. To illustrate the powerfulness of this simple tool, we show how Amazonia! reveals the specific expression of the tight junction protein Claudin 6 in hu- man embryonic stem cells and human induced stem cells (iPS), or the tissue specific expression of some chemokines and their receptors such as CCL16 in liver and CX3CR1 in central nervous system samples. Thus, Amazonia! advantageously complements large public repositories by providing a simple way to query a compilation of selected human transcriptome data. The tool is freely available at http://www.amazonia.transcriptome.eu/

JAK1 mutations are not frequent events in adult T-ALL: a GRAALL study

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Mast cell leukemia: identification of a new c-Kit mutation, dup(501-502), and response to masitinib, a c-Kit tyrosine kinase inhibitor.

Objective:  Most patients with systemic mastocytosis bear mutations in the tyrosine kinase receptor gene c‐Kit. Limited treatment options exist for mast cell leukemia, a rare form of systemic mastocytosis associated with a dire prognosis. Our aim was to investigate c‐Kit mutations associated with mast cell leukemia and find new treatment for this severe form of mastocytosis.

ASXL1 but Not TET2 Mutations Adversely Impact Overall Survival of Patients Suffering Systemic Mastocytosis with Associated Clonal Hematologic Non-Mast-Cell Diseases

Systemic mastocytosis with associated hematologic clonal non-mast cell disease (SM-AHNMD) is a rare and heterogeneous subtype of SM and few studies on this specific entity have been reported. Sixty two patients with Systemic mastocytosis with associated hematologic clonal non-mast cell disease (SM-AHNMD) were presented. Myeloid AHNMD was the most frequent (82%) cases. This subset of patients were older, had more cutaneous lesions, splenomegaly, liver enlargement, ascites; lower bone mineral density and hemoglobin levels and higher tryptase level than lymphoid AHNMD. Defects in KIT, TET2, ASXL1 and CBL were positive in 87%, 27%, 14%, and 11% of cases respectively. The overall survival of patients with SM-AHNMD was 85.2 months. Within the myeloid group, SM-MPN fared better than SM-MDS or SM-AML (p = 0.044,). In univariate analysis, the presence of C-findings, the AHNMD subtypes (SM-MDS/CMML/AML versus SM-MPN/hypereosinophilia) (p = 0.044), Neutropenia (p = 0.015), high monocyte level (p = 0.015) and the presence of ASXL1 mutation had detrimental effects on OS (p = 0.007). In multivariate analysis and penalized Cox model, only the presence of ASXL1 mutation remained an independent prognostic factor that negatively affected OS (p = 0.035). SM-AHNMD is heterogeneous with variable prognosis according to the type of the AHNMD. ASXL1 is mutated in a subset of myeloid AHNMD and adversely impact on OS.

Long-term efficacy and safety of cladribine (2-CdA) in adult patients with mastocytosis

Mastocytosis (M) is a clonal myeloid-disabling disorder for which no curative therapy is currently available. Cladribine (2-chlorodeoxyadenosine [2-CdA]) is a synthetic purine analog cytoreductive treatment, for which efficacy is mostly reported in advanced M. Here we report, with a long-term follow-up period (>10 years) efficacy and safety in 68 adult patients with M (36 [53%] had indolent M and 32 [47%] had advanced M) treated by 2-CdA (0.14 mg/kg in infusion or subcutaneously, days 1-5; repeated at 4-12 weeks until 1 to 9 courses). Median 2-CdA courses number was 3.7 (1-9). The overall response rate was 72% (complete remission [R]/major/partial R: 0%/47%/25%) and according to indolent/advanced M was 92% (major/partial R: 56%/36%) and 50% (major/partial R: 37.5%/12.5%), respectively. Clinical improvement was observed for 10 of 11 mediator release and 6 of 7 mast cell infiltration-related symptoms including urticaria pigmentosa and organomegaly (P < .02). Serum tryptase levels decreased (P = .01). Median durations of response were 3.71 (0.1-8) and 2.47 (0.5-8.6) years for indolent and aggressive M, respectively. The most frequent grade 3/4 toxicities were lymphopenia (82%), neutropenia (47%), and opportunistic infections (13%). 2-CdA appears to provide a significant efficacy with some toxicity in various M subtypes, mostly in indolent M, refractory to multiple symptomatic therapies.

Masitinib for treatment of severely symptomatic indolent systemic mastocytosis: a randomised, placebo-controlled, phase 3 study

BACKGROUND Indolent systemic mastocytosis, including the subvariant of smouldering systemic mastocytosis, is a lifelong condition associated with reduced quality of life. Masitinib inhibits KIT and LYN kinases that are involved in indolent systemic mastocytosis pathogenesis. We aimed to assess safety and efficacy of masitinib versus placebo in severely symptomatic patients who were unresponsive to optimal symptomatic treatments. METHODS In this randomised, double-blind, placebo-controlled, phase 3 study, we enrolled adults (aged 18-75 years) with indolent or smouldering systemic mastocytosis, according to WHO classification or documented mastocytosis based on histological criteria, at 50 centres in 15 countries. We excluded patients with cutaneous or non-severe systemic mastocytosis after a protocol amendment. Patients were centrally randomised (1:1) to receive either oral masitinib (6 mg/kg per day over 24 weeks with possible extension) or matched placebo with minimisation according to severe symptoms. The primary endpoint was cumulative response (≥75% improvement from baseline within weeks 8-24) in at least one severe baseline symptom from the following: pruritus score of 9 or more, eight or more flushes per week, Hamilton Rating Scale for Depression of 19 or more, or Fatigue Impact Scale of 75 or more. We assessed treatment effect using repeated measures methodology for rare diseases via the generalised estimating equation model in a modified intention-to-treat population, including all participants assigned to treatment minus those who withdrew due to a non-treatment-related cause. We assessed safety in all patients who received at least one dose of study drug. This trial is registered with ClinicalTrials.gov, number NCT00814073. FINDINGS Between Feb 19, 2009, and July 15, 2015, 135 patients were randomly assigned to masitinib (n=71) or placebo (n=64). By 24 weeks, masitinib was associated with a cumulative response of 18·7% in the primary endpoint (122·6 responses of 656·5 possible responses [weighted generalised estimating equation]) compared with 7·4% for placebo (48·9 of 656·5; difference 11·3%; odds ratio 3·6; 95% CI 1·2-10·8; p=0·0076). Frequent severe adverse events (>4% difference from placebo) were diarrhoea (eight [11%] of 70 in the masitinib group vs one [2%] of 63 in the placebo group), rash (four [6%] vs none), and asthenia (four [6%] vs one [2%]). The most frequent serious adverse events were diarrhoea (three patients [4%] vs one [2%]) and urticaria (two [3%] vs none), and no life-threatening toxicities occurred. One patient in the placebo group died (unrelated to study treatment). INTERPRETATION These study findings indicate that masitinib is an effective and well tolerated agent for the treatment of severely symptomatic indolent or smouldering systemic mastocytosis. FUNDING AB Science (Paris, France).

Blood CD34−c-Kit+ cell rate correlates with aggressive forms of systemic mastocytosis and behaves like a mast cell precursor

Mastocytosis is a heterogeneous disease characterized by the accumulation of mast cells in one or more organs. Our objective was to identify a peripheral mast cell precursor and assess its variation rate in mastocytosis. A peripheral blood phenotypic analysis was performed among 50 patients with mastocytosis who were enrolled in a prospective multicentric French study, and the phenotypic analysis results of the patients were compared with those of healthy donors. The rate of peripheral blood CD34(-)c-Kit(+) cells correlated with the severity of mastocytosis. This cellular population was isolated from healthy donors as well as from patients with systemic mastocytosis. After 30 days of culture, the CD34(-)c-Kit(+) cells gave birth to mature mast cells, indicating that this cellular population constitutes a mast cell circulating precursor. Monitoring peripheral CD34(-)c-Kit(+) cells by flow cytometry could be a useful and low-invasive tool to determine the disease severity and the relapses and to assess treatment efficiency.

Midostaurin in Advanced Systemic Mastocytosis

The use of midostaurin, a multikinase inhibitor, has been associated with a response in 60% of patients with systemic mastocytosis, including mast-cell leukemia; the median overall survival was 28 months. A second, smaller trial in France showed a 71% response rate.