Investigation of constitutional biomarkers in patients with acute myeloid leukemia treated with cytarabine

La Cytarabine (AraC) est actuellement l’un des piliers du traitement de la Leucémie Aigüe Myéloïde (LAM) en association lors de l’induction puis en monothérapie durant les cures de consolidation. Le métabolisme de l’AraC fait intervenir deux enzymes, la deoxyCytidine Kinase (dCK) et la cytidine déaminase (CDA). La CDA est soumise à une forte variabilité inter-individuelle.L’objectif de ce projet était de préciser l’impact de l’activité de la CDA sur la pharmacocinétique (PK) et la pharmacodynamie (PD) de l'AraC utilisée de façon standard ou liposomale, chez ces patients. Après avoir développé des techniques bioanalytiques séparatives permettant de mesurer les concentrations d'AraC dans le plasma, développé le génotypage des gènes de la CDA/dCK. Les patients LAM étaient évalués (phéno/génotypage) sur l’activité CDA, génotypés sur la dCK, et ont fait l’objet d’un suivi PK après traitement par AraC standard ou liposomale. Nos résultats ont permis de confirmer la variabilité inter-individuelle de l’activité de la CDA, de montrer une forte prévalence du statut CDA déficient au sein de notre population de patients. Nos données ont mis en évidence que la PK de l'AraC standard ou liposomale dépendait essentiellement du statut CDA des patients au moment de la cure. Les patients déficitaires présentaient une exposition plasmatique supérieure en AraC, une plus grande propension à développer des toxicités sévères voire mortelles, des réductions de doses consenties à la suite des toxicités observées et enfin une efficacité moindre. Nos données suggèrent que le statut CDA pourrait être utilisé comme une variable d’ajustement des schémas posologiques des patients LAM traités par AraCCytarabine (Ara-C) is currently one of the mainstays of treatment for acute myeloid leukemia (AML), prescribed in combination (anthracyclines + Ara-C), according to the so-called "7+3" regimen during the induction treatment, and then most often as monotherapy during the consolidation treatment. Cytidine deaminase (CDA) is the enzyme responsible for the catabolism of Ara-C and is subject to extreme inter-individual variability. The objective of this project was to clarify the impact of CDA variability on the pharmacokinetics and pharmacodynamics (efficacy, toxicity) of Cytarabine used in standard or liposomal form in patients with AML. After developing separative bioanalytical techniques to measure Cytarabine concentrations in plasma, we developed genotyping of the genes coding for CDA and deoxyCytidine Kinase (dCK). AML patients were then evaluated (phenotyping + genotyping) depending on CDA activity, genotyped for dCK, and pharmacokinetics study after treatment with standard or liposomal Cytarabine. Our results showed that CDA-deficiency was very frequently found in our patient population (between 50% and 80%), that the dCK genotype was not directly contributing to the understanding of pharmacodynamic phenomena, and that the pharmacokinetics of standard or liposomal Cytarabine depended essentially on CDA status. Deficient patients had a higher plasma exposure to cytarabine, a greater propensity to develop severe and even fatal toxicities, but also a lower efficacy, probably due to dose reductions following the observed toxicities. Our data suggest that CDA status could be used as an adjustment variable for Cytarabine-treated AML patient

Approche intégrative du VYXEOS® : du flacon au patient

La Leucémie Aigüe Myéloïde (LAM), est une hémopathie maligne caractérisée par une prolifération de cellules myéloïdes immatures présentant une différenciation variable. Les LAM représentent un groupe de maladies biologiques hétérogènes impliquant le plus souvent la moelle osseuse et le sang périphérique. Elles peuvent toutefois se manifester dans les tissus extra-médullaires.Aujourd’hui et ce, depuis plusieurs décennies, la Cytarabine est un des deux piliers dans le traitement de la LAM en association avec des Anthracyclines selon un schéma « 7+3 » lors de la cure d’induction et le plus souvent en monothérapie durant les cures de consolidation. La Cytarabine et les Anthracyclines se présentent sous forme de solutions et sont administrées par voie intra-veineuse (IV). Leur activité n’est pas ciblée, par conséquent, celle-ci peut s’accompagner d’effets secondaires généraux comme des pancytopénies ou encore des toxicités cardiaques décrites pour les Anthracyclines. Ces toxicités pouvant conduire parfois jusqu’au décès toxique du patient, d’où l’intérêt des recherches qui ont conduit à une nouvelle formulation : le Vyxeos®.En effet, en août 2017, la Food and Drug Administration (FDA), a approuvé le Vyxeos® (Jazz Pharmaceutical), une formulation liposomale caractérisée par une co-encapsulation de Daunorubicine et Cytarabine (44mg/100 mg, respectivement) avec un ratio molaire fixe de 5 : 1), indiquée dans le traitement des patients adultes présentant une LAM nouvellement diagnostiquée, secondaire à un traitement (LAM-t) ou avec des anomalies associées aux myélodysplasies (LAM-MRC). Le Vyxeos® a obtenu une autorisation temporaire d’utilisation (ATU) de cohorte en France en juillet 2018, puis l’AMM pour cette même indication en août 2018

CDA as a predictive marker for life-threatening toxicities in patients with AML treated with cytarabine

International audienceKey Points Ara-C is the mainstay of treatment for patients with AML, and life-threatening toxicities are common. We demonstrated that cytidine deaminase downregulation predicts severe/lethal toxicities with cytarabine

Pharmacokinetics and pharmacogenetics of liposomal cytarabine in AML patients treated with CPX-351

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Simultaneous determination of cytosine arabinoside and its metabolite uracil arabinoside in human plasma by LC-MS/MS: Application to pharmacokinetics-pharmacogenetics pilot study in AML patients

International audiencePurine analogs like aracytine (AraC) are a mainstay for treating acute myeloid leukemia (AML). There are marked differences in drug dosing and scheduling depending on the protocols when treating AML patients with AraC. Large inter-patient pharmacokinetics variability has been reported, and genetic polymorphisms affecting cytidine deaminase (CDA), the liver enzyme responsible for the conversion of Ara-C to inactive uracil arabinoside (AraU) could be a culprit for either life-threatening toxicities or poor efficacy related to substantial changes in plasma exposure levels among patients. The quantitative determination of Ara-C in plasma is challenging due the required sensitivity because of the short half-life of this drug (i.e., <10 min) and the metabolic instability in biological matrix upon sampling possibly resulting in erratic values. We developed and validated a liquid chromatography tandem mass spectrometry method (UPLC-MS/MS) for the simultaneous determination of Ara-C and Ara-U metabolite in human plasma. After simple and rapid precipitation, analytes were successfully separated and quantitated over a 1-500 ng/ml range for Ara-C and 250-7500 ng/ml range for AraU. The performance and reliability of this method was tested as part of an investigational study in AML patients treated with low dose cytarabine and confirmed marked differences in drug exposure levels and metabolic ratio, depending on the CDA status of the patients. Overall, this new method meets the requirements of current bioanalytical guidelines and could be used to monitor drug levels in AML patients with respect to their CDA phenotypes

A New Thienopyrimidinone Chemotype Shows Multistage Activity against Plasmodium falciparum, Including Artemisinin-Resistant Parasites

International audienceHuman malaria infection begins with a one-time asymptomatic liver stage followed by a cyclic symptomatic blood stage. For decades, the research for novel antimalarials focused on the high-throughput screening of molecules that only targeted the asexual blood stages. In a search for new effective compounds presenting a triple action against erythrocytic and liver stages in addition to the ability to block the transmission of the disease via the mosquito vector, 2-amino-thienopyrimidinone derivatives were synthesized and tested for their antimalarial activity. One molecule, named gamhepathiopine (denoted as “M1” herein), was active at submicromolar concentrations against both erythrocytic (50% effective concentration [EC50] = 0.045 μM) and liver (EC50 = 0.45 μM) forms of Plasmodium falciparum. Furthermore, gamhepathiopine efficiently blocked the development of the sporogonic cycle in the mosquito vector by inhibiting the exflagellation step. Moreover, M1 was active against artemisinin-resistant forms (EC50 = 0.227 μM), especially at the quiescent stage. Nevertheless, in mice, M1 showed modest activity due to its rapid metabolization by P450 cytochromes into inactive derivatives, calling for the development of new parent compounds with improved metabolic stability and longer half-lives. These results highlight the thienopyrimidinone scaffold as a novel antiplasmodial chemotype of great interest to search for new drug candidates displaying multistage activity and an original mechanism of action with the potential to be used in combination therapies for malaria elimination in the context of artemisinin resistance.IMPORTANCE This work reports a new chemical structure that (i) displays activity against the human malaria parasite Plasmodium falciparum at 3 stages of the parasitic cycle (blood stage, hepatic stage, and sexual stages), (ii) remains active against parasites that are resistant to the first-line treatment recommended by the World Health Organization (WHO) for the treatment of severe malaria (artemisinins), and (iii) reduces transmission of the parasite to the mosquito vector in a mouse model. This new molecule family could open the way to the conception of novel antimalarial drugs with an original multistage mechanism of action to fight against Plasmodium drug resistance and block interhuman transmission of malaria

Enteric pathogenic bacteria and resistance gene carriage in the homeless population in Marseille, France

International audienceAbstract We aimed to assess the prevalence of pathogenic bacteria and resistance genes in rectal samples collected among homeless persons in Marseille, France. In February 2014 we enrolled 114 sheltered homeless adults who completed questionnaires and had rectal samples collected. Eight types of enteric bacteria and 15 antibiotic resistance genes (ARGs) were sought by real-time polymerase chain reaction (qPCR) performed directly on rectal samples. ARG-positive samples were further tested by conventional PCR and sequencing. We evidenced a 17.5% prevalence of gastrointestinal symptoms, a 9.6% prevalence of enteric pathogenic bacteria carriage, including Escherichia coli pathotypes (8.7%) and Tropheryma whipplei (0.9%). Only 2 persons carried bla CTX-M-15 resistance genes (1.8%), while other genes, including carbapenemase-encoding genes and colistin-resistance genes, ( mcr -1 to mcr - 6, mcr-8 ) were not detected. Our results suggest that sheltered homeless persons in Marseille do not have a high risk of harbouring gastrointestinal antibiotic resistant bacteria