Publications by authors named "Noel Zahr"

Background: Ceftobiprole is a broad-spectrum cephalosporin. It is currently approved for the treatment of community- and hospital-acquired pneumonia. However, the recommended dosage regimen of ceftobiprole may not be sufficient to achieve the optimal pharmacokinetic/pharmacodynamic criterion in critically ill patients.

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Background: Kidney transplant recipients are prescribed an immunosuppressive therapy (IST) and some of them follow a high fat diet (HFD) despite medical recommendations. Both are frequently associated with gut microbiota changes and metabolic disorders. We aimed at precisely identifying the effect of the IST and the HFD on metabolic parameters and the gut microbiota in mice, and at establishing correlations between the latters.

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Background: Immune checkpoint inhibitor (ICI)-induced myocarditis is a life-threatening adverse drug reaction. Abatacept (a CTLA-4-immunoglobulin fusion protein) has been proposed as a compassionate-use treatment for ICI myocarditis (in combination with corticosteroids and ruxolitinib) but no clinical trial has yet been performed. The abatacept dose can be adjusted using real-time assessment of its target, the CD86 receptor occupancy on circulating monocytes (CD86RO).

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Objective: Previous studies have provided evidence that the discontinuation of hydroxychloroquine (HCQ), and chloroquine (CQ), in patients with systemic lupus erythematosus (SLE) is associated with an increased risk of disease flares, with limited information on the level of disease activity at the time of HCQ/CQ discontinuation. Here we aimed to describe the risk of SLE flare after withdrawal of HCQ or CQ in patients with SLE in remission.

Methods: Case-control study (1:2) comparing the evolution of patients with SLE after HCQ/CQ withdrawal for antimalarial retinopathy (cases) with patients with SLE matched for sex, antimalarial treatment duration and age at SLE diagnosis, whose antimalarial treatment was continued throughout the entire follow-up period (controls).

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Background: Long-term hydroxychloroquine (HCQ) or chloroquine (CQ) intake causes retinal toxicity in 0.3-8 % of patients with rheumatic diseases. Numerous risk factors have been described, eg, daily dose by weight, treatment duration, chronic kidney disease, concurrent tamoxifen therapy and pre-existing retinal or macular disease.

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Therapeutic drug monitoring (TDM) involves measuring and interpreting drug concentrations in biological fluids to adjust drug dosages. In onco-hematology, TDM guidelines for oral molecular targeted therapies (oMTTs) are varied. This study evaluates a quantitative approach with a score to predict the clinical usefulness of TDM for oMTTs.

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Introduction: Aromatase inhibitors such as anastrozole, letrozole, exemestane and selective estrogen down-regulator (SERD) fulvestrant are used mostly to treat breast cancer estrogen receptor positive in post-menopausal women. These drugs are given either through the oral route or by intramuscular injection. They have shown great inter-individual variability with a risk of cardiometabolic disorders.

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Article Synopsis
  • Belimumab is a monoclonal antibody effective in treating systemic lupus erythematosus (SLE), available in both intravenous and subcutaneous forms, prompting a study to develop a reliable method for measuring its levels in human serum.
  • The study utilized a technique called nano-surface and molecular-orientation limited (nSMOL) proteolysis combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) for quantification, achieving a total assay time of 10 minutes with high accuracy and precision.
  • Results revealed that belimumab concentrations were significantly higher in patients receiving subcutaneous administration compared to intravenous, and the developed method can enhance future research on belimumab's effectiveness and safety in SLE treatment
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Cefiderocol is a broad-spectrum cephalosporin antibiotic and is indicated in patients with difficult-to-treat Gram-negative bacterial infections. Cefiderocol is applied as a 2-4-times daily prolonged 3-h infusion. The therapeutic target of cefiderocol suggests that continuous infusion (CI) may be advantageous, since it is more likely to achieve 100% of time of the unbound concentration above the minimal inhibitory concentration (MIC).

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Introduction: The number of cancer patients receiving long-term hemodialysis (HD) is increasing, and HD could jeopardize treatments' safety and efficacy. Therefore, managing anticancer drugs is critical in this frail population. In addition, evidence of HD safety or risk is regularly released both for cytotoxic chemotherapy (CT) or hormone therapy (HT) as well as new therapies with molecularly targeted therapies (MTT), immune checkpoint inhibitors (ICI), and a summary of current knowledge is needed.

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Therapeutic antibodies targeting immune checkpoints have shown limited efficacy in clinical trials in glioblastoma (GBM) patients. Ultrasound-mediated blood-brain barrier opening (UMBO) using low-intensity pulsed ultrasound improved drug delivery to the brain. We explored the safety and the efficacy of UMBO plus immune checkpoint inhibitors in preclinical models of GBM.

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Article Synopsis
  • The study investigates the connection between immune-checkpoint inhibitor (ICI)-associated myotoxicity, specifically looking at myocarditis and myositis, which can be life-threatening.
  • It details a treatment strategy that involved the use of mechanical ventilation for respiratory muscle issues and the administration of the drugs abatacept and ruxolitinib in patients diagnosed with severe ICI myocarditis.
  • Results showed a significant drop in myotoxicity-related fatalities from 60% in the initial patient group to just 3.4% in the later group, indicating the effectiveness of early intervention and specific treatment adjustments.
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  • - The study investigated the pharmacokinetics of ceftobiprole in patients with ECMO-related cannula infections, comparing blood levels in patients on ECMO versus those after ECMO removal.
  • - Among 35 patients studied, 29 had confirmed infections, with a high susceptibility of isolated pathogens to ceftobiprole, and blood levels were similar in both ECMO and non-ECMO patients.
  • - Ceftobiprole blood levels were lower in patients with acute renal failure needing renal replacement therapy, and in those with high renal clearance, but overall pharmacokinetics remained unchanged during and after ECMO.
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Background: Cefiderocol is a siderophore cephalosporin antibiotic active against Gram-negative bacteria, including extended-spectrum beta-lactamase and carbapenemase-producing strains. The pharmacokinetics of cefiderocol has been studied in healthy subjects and particularly in phase II and III studies. This retrospective study investigated intravenous cefiderocol population pharmacokinetics in adult patients treated by cefiderocol.

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Objectives: All guidelines recommend LC-MS/MS as the analytical method of choice for the quantification of immunosuppressants in whole blood. Until now, the lack of harmonization of methods and the complexity of the analytical technique have prevented its widespread use in clinical laboratories. This can be seen in international proficiency schemes, where more than half of the participants used immunoassays.

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Objectives: Type-I interferons (IFNs-I) have potent antiviral effects. IFNs-I are also overproduced in patients with systemic lupus erythematosus (SLE). Autoantibodies (AAbs) neutralising IFN-α, IFN-β and/or IFN-ω subtypes are strong determinants of hypoxemic COVID-19 pneumonia, but their impact on inflammation remains unknown.

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Immune-checkpoint inhibitors (ICI) have revolutionized cancer therapy but are associated with infrequent but lethal myocarditis, for which management remains uncertain. Abatacept, a CTLA-4 fusion protein targeting CD86 on antigen presenting cells and leading to global T-cell anergy, has been described as a potential treatment in individual reports. Yet, abatacept treatment dosage, schedule and optimal combination with other immunosuppressive therapies are unclear.

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The MYOMEX study was a multicentre, randomised, double-blind, placebo-controlled, cross-over study aimed to compare the effects of mexiletine vs. placebo in patients with myotonia congenita (MC) and paramyotonia congenita (PC). The primary endpoint was the self-reported score of stiffness severity on a 100 mm visual analogic scale (VAS).

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Background And Objectives: To describe the marked clinical and biological responses of a targeted treatment with anti-interleukin-6 (IL-6)-receptor antibody and Janus kinase (JAK) inhibitors in a patient with a severe, corticoresistant CNS toxicity of immune-checkpoint inhibitor (ICI) therapy.

Methods: A 58-year-old man was admitted for subacute paraparesis, urinary retention, and ascending paresthesia. He was under treatment with ipilimumab and nivolumab for metastatic melanoma.

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Background: Ciprofloxacin is an antibiotic used in osteoarticular infections owing to its very good bone penetration. Very few pharmacokinetic data are available in this population.

Objectives: To investigate oral ciprofloxacin population pharmacokinetics in adult patients treated for osteoarticular infections and propose guidance for more effective dosing.

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Article Synopsis
  • Cefiderocol and ceftobiprole are advanced antibiotics with variable plasma concentrations that could affect their effectiveness, prompting the need for a reliable method to monitor their levels in patients, especially those critically ill.
  • A new, efficient UPLC-MS/MS method was developed for simultaneously measuring both drugs in human plasma, featuring fast analysis times and high accuracy across various metrics.
  • The validated method demonstrated robust performance in quantifying drug levels in critically ill patients, aiding in therapeutic drug monitoring and the optimization of antibiotic treatment.
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