Suboptimal exposure to fluconazole in critically ill patients: Pharmacokinetic analysis and determinants.

OBJECTIVES: This study aims at evaluating fluconazole exposure in critically ill patients and identifying variables associated with the latter. PATIENTS AND METHODS: This was a 2-year (2018-2019) retrospective multicenter cohort study. Adult patients > 18 years-old with at least one fluconazole concentration measurement during their ICU stay were included. RESULTS: Twenty patients were included. Only 11 patients had a fluconazole trough concentration (Cmin) within the target range (≥15 mg/L). According to bivariable analysis, SOFA score, GGT, fluconazole clearance, Ke, and Vd, were independently associated with a decrease in fluconazole Cmin. The median loading dose required to achieve the Cmin target appeared to be greater in patients with higher SOFA or GGT level and in patients undergoing renal replacement therapy. CONCLUSIONS: This study supports recommendation for routine fluconazole therapeutic drug monitoring in ICU patients so as to avoid underexposure, especially if SOFA score is ≥ 7 and/or GGT is ≥ 100 U/L.

Thesaurus for off-label indications for systemic antifungal agents.

OBJECTIVES: Following the removal of temporary treatment protocol procedures, we developed a thesaurus for off-label indications for systemic antifungals at our facility to update clinical practices and to control off-label prescriptions. MATERIALS AND METHODS: Clinical practice guidelines and literature data were analyzed. This work was part of an antifungal stewardship program. RESULTS: Off-label wording (prophylaxis, preemptive, empirical, curative) and corresponding antifungals and references were validated by the multidisciplinary group for antifungal agents under the aegis of the Commission for the use of drugs and sterile medical devices and of the anti-infective committee. CONCLUSION: Considering the complexity of invasive fungal infection management, this thesaurus needs to be shared and used as a helping tool to review off-label situations.

[How to act when an alpha-blocker is associated with a potent inhibitor of CYP3A4]. / Conduite à tenir en cas d'association d'un alpha-bloquant et d'un inhibiteur puissant du cytochrome 3A4.

OBJECTIVE: Combination of alpha-blockers with potent CYP3A4 inhibitors is either contra-indicated or not recommended. We searched data supporting this classification and guiding prescribers when such an interaction occurs. METHODS: We analyzed reports published by the French agency for drug safety, reference books and performed search in databases of pharmacokinetics studies and case or case series related with these interactions. RESULTS: The classification of the potential severity of these interactions defined by the French agency for drug safety evolved over time. Our literature search did not identify any cases or case series reporting serious clinical consequences of such interactions and no pharmacoepidemiological studies on the association between alpha-blockers and inhibitors of CYP3A4. The content of the summaries of product characteristics indicate that the combination of ketoconazole with alfuzosin, silodosin and tamsulosin increases the area under the curve of the alpha-blocker 3 fold. CONCLUSION: Data demonstrating the clinical consequences of an association between alpha-blocker and a potent CYP3A4 inhibitor are lacking. The 3 fold increase of the area under the curve for alfuzosin, silodosin and tamsulosin associated with ketoconazole while the association with the two first is contra-indicated and is not recommended with the third raises questions. This lack of data leaves doctors and pharmacists in a situation of uncertainty on how to proceed when such an interaction occurs.

A Model for Predicting the Interindividual Variability of Drug-Drug Interactions.

Pharmacokinetic drug-drug interactions are frequently characterized and quantified by an AUC ratio (Rauc). The typical value of the AUC ratio in case of cytochrome-mediated interactions may be predicted by several approaches, based on in vitro or in vivo data. Prediction of the interindividual variability of Rauc would help to anticipate more completely the consequences of a drug-drug interaction. We propose and evaluate a simple approach for predicting the standard deviation (sd) of Ln(Rauc), a metric close to the interindividual coefficient of variation of Rauc. First, a model was derived to link sd(Ln Rauc) with the substrate fraction metabolized by each cytochrome and the potency of the interactors, in case of induction or inhibition. Second, the parameters involved in these equations were estimated by a Bayesian hierarchical model, using the data from 56 interaction studies retrieved from the literature. Third, the model was evaluated by several metrics based on the fold prediction error (PE) of sd(Ln Rauc). The median PE was 0.998 (the ideal value is 1) and the interquartile range was 0.96-1.03. The PE was in the acceptable interval (0.5 to 2) in 52 cases out of 56. Fourth, a surface plot of sd(Ln Rauc) as a function of the characteristics of the substrate and the interactor has been built. The minimal value of sd(Ln Rauc) was about 0.08 (obtained for Rauc = 1) while the maximal value, 0.7, was obtained for interactions involving highly metabolized substrates with strong interactors.

[Identification of knowledge deficits of pharmacy students at the beginning of the fifth year of pharmacy practice experience: Proposals to change the content of academic programs]. / Identification des lacunes de connaissances des étudiants en filière officine débutant le stage de 5(e) année : propositions pour modifier le contenu de l'enseignement.

INTRODUCTION: In France, community pharmacy students performed a hospital pharmacy practice experience during the 5th year of the university curriculum. The purpose of a part of the content of the academic teaching program delivered before this practice experience is to prepare the students for their future hospital activities. It should enable them for the practical use of knowledge in order to improve pharmacotherapy, laboratory diagnosis and monitoring of patients' care. The aim of this study was to show if there are gaps in this program. METHODS: Fourteen students performing their clerkship in a teaching hospital were invited to highlight these gaps when they were gradually immersed in the pharmaceutical care. They did so under the careful observation of hospital pharmacist preceptors. These practitioners referred to professional guidelines, documentary tools used in daily clinical practice and publications supporting their pharmaceutical care practices. RESULTS: Shortcomings and gaps identified were: how to communicate with other healthcare professionals and the content of verbal exchanges, how to conduct a patient-centered consultation, documentation tools required for relevant pharmacist' interventions, codification of pharmacist's interventions, risks related to drug packaging and benefit risk assessment of health information technologies. DISCUSSION: These gaps represent a handicap by delaying the process that led to move from student to healthcare professional. Hospital pharmacist preceptors have to fill in these gaps before engaging students in pharmaceutical care. CONCLUSION: These results invite to revise partly the content of the academic teaching program delivered before the 5th year hospital pharmacy practice experience.

A Joint Model for the Kinetics of CTC Count and PSA Concentration During Treatment in Metastatic Castration-Resistant Prostate Cancer.

Assessment of treatment efficacy in metastatic castration-resistant prostate cancer (mCRPC) is limited by frequent nonmeasurable bone metastases. The count of circulating tumor cells (CTCs) is a promising surrogate marker that may replace the widely used prostate-specific antigen (PSA). The purpose of this study was to quantify the dynamic relationships between the longitudinal kinetics of these markers during treatment in patients with mCRPC. Data from 223 patients with mCRPC treated by chemotherapy and/or hormonotherapy were analyzed for up to 6 months of treatment. A semimechanistic model was built, combining the following several pharmacometric advanced features: (1) Kinetic-Pharmacodynamic (K-PD) compartments for treatments (chemotherapy and hormonotherapy); (2) a latent variable linking both marker kinetics; (3) modeling of CTC kinetics with a cell lifespan model; and (4) a negative binomial distribution for the CTC random sampling. Linked with survival, this model would potentially be useful for predicting treatment efficacy during drug development or for therapeutic adjustment in treated patients.

Modeling and predicting optimal treatment scheduling between the antiangiogenic drug sunitinib and irinotecan in preclinical settings.

We present a system of nonlinear ordinary differential equations used to quantify the complex dynamics of the interactions between tumor growth, vasculature generation, and antiangiogenic treatment. The primary dataset consists of longitudinal tumor size measurements (1,371 total observations) in 105 colorectal tumor-bearing mice. Mice received single or combination administration of sunitinib, an antiangiogenic agent, and/or irinotecan, a cytotoxic agent. Depending on the dataset, parameter estimation was performed either using a mixed-effect approach or by nonlinear least squares. Through a log-likelihood ratio test, we conclude that there is a potential synergistic interaction between sunitinib when administered in combination with irinotecan in preclinical settings. Model simulations were then compared to data from a follow-up preclinical experiment. We conclude that the model has predictive value in identifying the therapeutic window in which the timing between the administrations of these two drugs is most effective.

Role of the lean body mass and of pharmacogenetic variants on the pharmacokinetics and pharmacodynamics of sunitinib in cancer patients.

INTRODUCTION: Sunitinib is a multikinase inhibitor active in various cancers types including renal cancers and endocrine tumors. The study analyzed the influence of the lean body mass (LBM) and of pharmacogenetic variants on the exposure to sunitinib and its active metabolite, SU12662, and on sunitinib toxicity and clinical activity. MATERIALS AND METHODS: Exposure to sunitinib and SU12662 was assessed on days 10 and 21 during the first treatment cycle. Acute toxicity was graded using the NCI 4.0 CTCAE ver. 4.0. The LBM and 14 common single nucleotide polymorphisms in the CYP3A4/3A5, NR1I2, NR1I3, ABCB1, and ABCG2 genes were analyzed according to the drug exposure at day 10. Determinants (including sunitinib exposure and pharmacogenetic variants) for toxicities were assessed, as well as the relationship between drug exposure and survival in renal cancer patients. RESULTS: Ninety-two patients (60 % with renal cancer) were assessable for pharmacokinetics, toxicity and survival, and 66 for genetic analysis. The LBM (p < 0.0001) and a polymorphism in the ABCG2 transporter (421C>A) (p = 0.014) were two independent parameters accounting for the variability of composite (sunitinib + SU12662) exposure. Advanced age (OR = 1.47 [1.01-2.15], p = 0.048) and high sunitinib exposure (OR = 1.16 [1.05-1.28], p = 0.005) were independently associated with any grade ≥ 3 acute toxicity, and high SU12662 exposure was associated with grade ≥ 2 thrombocytopenia (OR = 1.27 [1.03-1.57], p = 0.028). A high composite area under the curve (AUC) >1,973 ng/mL∙h at day 21 was associated with a doubled survival (35.2 vs 16.7 months; log-rank p = 0.0051) in renal cancer patients. CONCLUSIONS: This study indicates that LBM and drug monitoring may be helpful in the management of sunitinib-treated patients.

Nonequilibrium dynamics of one-dimensional hard-core anyons following a quench: complete relaxation of one-body observables.

We demonstrate the role of interactions in driving the relaxation of an isolated integrable quantum system following a sudden quench. We consider a family of integrable hard-core lattice anyon models that continuously interpolates between noninteracting spinless fermions and strongly interacting hard-core bosons. A generalized Jordan-Wigner transformation maps the entire family to noninteracting fermions. We find that, aside from the singular free-fermion limit, the entire single-particle density matrix and, therefore, all one-body observables relax to the predictions of the generalized Gibbs ensemble (GGE). This demonstrates that, in the presence of interactions, correlations between particles in the many-body wave function provide the effective dissipation required to drive the relaxation of all one-body observables to the GGE. This relaxation does not depend on translational invariance or the tracing out of any spatial domain of the system.

Prediction of tumour response induced by chemotherapy using modelling of CA-125 kinetics in recurrent ovarian cancer patients.

BACKGROUND: The main objective of the present study was to establish the relationships between CA-125 kinetics and tumour size changes during treatment. METHODS: The data from the CALYPSO-randomised phase III trial, comparing two platinum-based regimens in recurrent ovarian cancer (ROC) patients, was randomly split into a 'learning data set' to estimate model parameters and a 'validation data set' to validate model performances. A kinetic-pharmacodynamic semi-mechanistic model was built to describe tumour size and CA-125 kinetics during chemotherapy. The ability of the model to predict tumour response induced by chemotherapy, based on CA-125 values, was assessed. RESULTS: Data from 535 ROC patients were used to model CA-125 kinetics and tumour size changes during the first 513 days after treatment initiation. Using the validated model, we could predict with accuracy the tumour size changes induced by chemotherapy based on the baseline imaging assessment and longitudinal CA-125 values (mean prediction error: 0.3%, mean absolute prediction error: 10.6%). CONCLUSIONS: Using a semi-mechanistic model, the dynamic relationships between tumour size changes and CA-125 kinetics induced by chemotherapy were established in ROC patients. A modelling approach allowed CA-125 to be assessed as a biomarker for tumour size dynamics, to predict treatment efficacy for research and clinical purposes.

A critical review of the analytical approaches for circulating tumor biomarker kinetics during treatment.

Changes in serum tumor biomarkers may indicate treatment efficacy. Traditional tumor markers may soon be replaced by novel serum biomarkers, such as circulating tumor cells (CTCs) or circulating tumor nucleic acids. Given their promising predictive values, studies of their kinetics are warranted. Many methodologies meant to assess kinetics of traditional marker kinetics during anticancer treatment have been reported. Here, we review the methodologies, the advantages and the limitations of the analytical approaches reported in the literature. Strategies based on a single time point were first used (baseline value, normalization, nadir, threshold at a time t), followed by approaches based on two or more time points [half-life (HL), percentage decrease, time-to-events…]. Heterogeneities in methodologies and lack of consideration of inter- and intra-individual variability may account for the inconsistencies and the poor utility in routine. More recently, strategies based on a population kinetics approach and mathematical modeling have been reported. The identification of equations describing individual kinetic profiles of biomarkers may be an alternative strategy despite its complexity and higher number of necessary measurements. Validation studies are required. Efforts should be made to standardize biomarker kinetic analysis methodologies to ensure the optimized development of novel serum biomarkers and avoid the pitfalls of traditional markers.

Early prediction of treatment resistance in low-risk gestational trophoblastic neoplasia using population kinetic modelling of hCG measurements.

BACKGROUND: In low-risk gestational trophoblastic neoplasia (GTN) patients, a predictive marker for early identification of methotrexate (MTX) resistance would be useful. We previously demonstrated that kinetic modelling of human chorionic gonadotrophin (hCG) measurements could provide such a marker. Here we validate this approach in a large independent patient cohort. METHODS: Serum hCG measurements of 800 low-risk GTN patients treated with MTX were analysed. The cohort was divided into Model and Test data sets. hCG kinetics were described from initial treatment day to day 50 using: '(hCG(time))=hCG0*exp(-k*time)+hCGres', where hCGres is the modelled residual production, hCG0 is the baseline hCG level, and k is the rate constant. HCGres-predictive value was investigated against previously reported predictors of MTX resistance. RESULTS: Declining hCG measurements were well fitted by the model. The best discriminator of MTX resistance in the Model data set was hCGres, categorised by an optimal cut-off value of >20.44 IU l(-1): receiver-operating characteristic (ROC) area under the curve (AUC)=0.87; Se=0.91; Sp=0.83. The predictive value of hCGres was reproducible using the Test data set: ROC AUC=0.87; Se=0.88; Sp=0.86. Multivariate analyses revealed hCGres as a better predictor of MTX resistance (HR=1.01, P<0.0001) and MTX failure-free survival (HR=13.25, P<0.0001) than other reported predictive factors. CONCLUSION: hCGres, a modelled kinetic parameter calculated after fully dosed three MTX cycles, has a reproducible value for identifying patients with MTX resistance.

Theoretical investigation of the efficacy of antiangiogenic drugs combined to chemotherapy in xenografted mice.

Antiangiogenic drugs were developed with the aim to inhibit the formation of intratumoral blood vessels and in consequence the growth of solid tumors. As these drugs are generally combined with classical cytotoxic drugs in the treatment of cancer patients, finding the optimal combinations remains a complex challenge due to possible interactions of the antiangiogenic compound with the hemodynamic property of the treated tumor. To analyze this problem, we developed a multi-scale model of vascular tumor growth combining a molecular model of VEGF signaling pathways and a tissue model of the tumor expansion including the dynamics of cellular and tissue processes of tumor growth and response to treatments. We addressed the potential impact of antiangiogenic drug by defining a new index of vasculature quality which depends on the balance between stable and unstable vessels within the tumor mass. Our goal was to investigate the interactions between a chemotherapy and a antiangiogenic treatment, and, by simulating the model, to identify the optimal delay of chemotherapy delivery after the administration of the antiangiogenic compound. This theoretical analysis could be used in the future to optimize antiangiogenic drug delivery in preclinical settings and to facilitate the translation from preclinical to clinical studies.

Eye pain: 5 cases to test your skill.

The ability to distinguish between ophthalmic emergencies and benign eye conditions is crucial for a family physician. Find out how your skills stack up.

Overdosed prescription of paracetamol (acetaminophen) in a teaching hospital.

INTRODUCTION: Paracetamol is the most commonly used analgesic and antipyretic. Reviews of hospital use of paracetamol are scarce. Little is known about the appropriateness of the dose of paracetamol prescribed for hospitalized adults. The aim of this study was to report on the nature and the frequency of the overdosed prescription of paracetamol observed in adult patients over a 4.5-year period in a teaching hospital. METHODS: Prescription analysis by pharmacists was performed once a week in six medical and three surgical departments and daily in a post-emergency unit. In cases of prescription error, the pharmacist notified the physician through an electronic alert when a computerized prescription order entry system was available or otherwise by face-to-face discussion. For each drug-related problem detected, the pharmacists recorded relevant details in a database. RESULTS: From October 2006 to April 2011, 44,404 prescriptions were reviewed and 480 alerts related to the overdosed prescription of paracetamol were made (1% of analyzed prescriptions). The extent of errors of dosage was within the intervals [90-120 mg/kg/d] and greater than 120 mg/kg/d for 87 and 11 patients respectively, who were prescribed a single non-combination paracetamol containing product. Sixty alerts concerned co-prescription of at least two paracetamol containing products with similar frequency for computerized (1.4/1000) or handwritten (1.2/1000) prescriptions. DISCUSSION: Prescriptions of paracetamol for hospitalized adults frequently exceed the recommended dosage. CONCLUSION: These results highlight the need for increased awareness of unintentional paracetamol overdose and support the initiation of an educational program aimed at physicians and nurses.

Sorafenib in advanced melanoma: a critical role for pharmacokinetics?

BACKGROUND: Inter-patient pharmacokinetic variability can lead to suboptimal drug exposure, and therefore might impact the efficacy of sorafenib. This study reports long-term pharmacokinetic monitoring of patients treated with sorafenib and a retrospective pharmacodynamic/pharmacokinetic analysis in melanoma patients. PATIENTS AND METHODS: Heavily pretreated patients with stage IV melanoma were started on sorafenib 400 mg twice daily (bid). In the absence of limiting toxicity, dose escalation of 200 mg bid levels was done every 2 weeks. Plasma sorafenib measurement was performed at each visit, allowing a retrospective pharmacodynamic/pharmacokinetic analysis for safety and efficacy. RESULTS: In all, 19 of 30 patients underwent dose escalation over 400 mg bid, and 28 were evaluable for response. The overall disease control rate was 61% (95% confidence interval (CI): 42.6-78.8), including three confirmed responses (12%). Disease control rate and progression-free survival (PFS) were improved in patients with high vs low exposure (80% vs 32%, P=0.02, and 5.25 vs 2.5 months, P=0.005, hazard ratio (HR)=0.28 (95% CI: 0.11-0.73)). In contrast, drug dosing had no effect on PFS. In multivariate analysis, drug exposure was the only factor associated with PFS (HR=0.36 (95% CI: 0.13-0.99)). Diarrhoea and anorexia were correlated with drug dosing, while hypertension and hand-foot skin reaction were correlated with drug exposure. CONCLUSIONS: Although sorafenib had modest efficacy in melanoma, these results suggest a correlation between exposure and efficacy of sorafenib. Therefore, dose optimisation in patients with low exposure at standard doses should be evaluated in validated indications.

Genotype-based quantitative prediction of drug exposure for drugs metabolized by CYP2D6.

We propose a framework to enable quantitative prediction of the impact of CYP2D6 polymorphisms on drug exposure. It relies mostly on in vivo data and uses two characteristic parameters: one for the drug and the other for the genotype. The metric of interest is the ratio of drug area under the curve (AUC) in patients with mutant genotype to the AUC in patients with wild-type genotype. Any combination of alleles, as well as duplications, may be accommodated in the framework. Estimates of the characteristic parameters were obtained by orthogonal regression for 40 drugs and five classes of genotypes, respectively, including poor, intermediate, and ultrarapid metabolizers (PMs, IMs, and UMs). The mean prediction error of AUC ratios was -0.05, and the mean prediction absolute error was 0.20. An external validation was also carried out. The model may be used to predict the variations in exposure induced by all drug-genotype combinations. An application of this model to a rare combination of alleles (*4*10) is described.