Impact of model-informed precision dosing in adults receiving vancomycin via continuous infusion: a randomized, controlled clinical trial.

BACKGROUND: Vancomycin is a commonly prescribed antibiotic to treat gram-positive infections. The efficacy of vancomycin is known to be directly related to the pharmacokinetic/pharmacodynamic (PK/PD) index of the area under the concentration-time curve (AUC) divided by the minimal inhibitory concentration (MIC) of the pathogen. However, in most countries, steady-state plasma concentrations are used as a surrogate parameter of target AUC/MIC, but this practice has some drawbacks. Hence, direct AUC-guided monitoring of vancomycin using model-informed precision dosing (MIPD) tools has been proposed for earlier attainment of target concentrations and reducing vancomycin-related nephrotoxicity. However, solid scientific evidence for these benefits in clinical practice is still lacking. This randomized controlled trial (RCT) aims to investigate the clinical utility of MIPD dosing of vancomycin administered via continuous infusion in hospitalized adults. METHODS: Participants from 11 wards at two Belgian hospitals are randomly allocated to the intervention group or the standard-of-care comparator group. In the intervention group, clinical pharmacists perform dose calculations using CE-labeled MIPD software and target an AUC24h of 400 to 600 mg × h/L, whereas patients in the comparator group receive standard-of-care dosing and monitoring according to the institutional guidelines. The primary endpoint is the proportion of patients reaching the target AUC24h/MIC of 400-600 between 48 and 72 h after start of vancomycin treatment. Secondary endpoints are the proportion of patients with (worsening) acute kidney injury (AKI) during and until 48 h after stop of vancomycin treatment, the proportion of patients reaching target AUC24h/MIC of 400-600 between 72 and 96 h after start of vancomycin treatment, and the proportion of time within the target AUC24h/MIC of 400-600. DISCUSSION: This trial will clarify the propagated benefits and provide new insights into how to optimally monitor vancomycin treatment. TRIAL REGISTRATION: EudraCT number: 2021-003670-31. Registered June 28, 2021. CLINICALTRIALS: gov identifier: NCT05535075. Registered September 10, 2022. Protocol version 3, protocol date: April 21, 2023.

Model-informed precision dosing of vancomycin via continuous infusion: a clinical fit-for-purpose evaluation of published PK models.

BACKGROUND: Model-informed precision dosing is an innovative approach used to guide bedside vancomycin dosing. The use of Bayesian software requires suitable and externally validated population pharmacokinetic (popPK) models. OBJECTIVES: This study aimed to identify suitable popPK models for a priori prediction and a posteriori forecasting of vancomycin in continuous infusion. Additionally, model averaging (MAA) and model selection approach (MSA) were compared with the identified popPK models. METHODS: Clinical pharmacokinetic data were retrospectively collected from patients receiving continuous vancomycin therapy and admitted to a general ward of three large Belgian hospitals. The predictive performance of the popPK models, identified in a systematic literature search, as well as the MAA/MSA were evaluated for the a priori and a posteriori scenarios using bias, root mean square errors, normalised prediction distribution errors and visual predictive checks. RESULTS: The predictive performance of 23 popPK models was evaluated based on clinical data from 169 patients and 923 therapeutic drug monitoring samples. Overall, the best predictive performance was found using the Okada et al. model (bias < -0.1 mg/L) followed by the Colin et al. MODEL: The MAA/MSA predicted with a constantly high precision and low inaccuracy and were clinically acceptable in the Bayesian forecasting. CONCLUSION: This study identified the two-compartmental models of Okada et al. and Colin et al. as most suitable for non-ICU patients to forecast individual exposure profiles after continuous vancomycin infusion. The MAA/MSA performed equally as well as the individual popPK models; therefore, both approaches could be used in clinical practice to guide dosing decisions.

A Large Retrospective Assessment of Voriconazole Exposure in Patients Treated with Extracorporeal Membrane Oxygenation.

BACKGROUND: Voriconazole is one of the first-line therapies for invasive pulmonary aspergillosis. Drug concentrations might be significantly influenced by the use of extracorporeal membrane oxygenation (ECMO). We aimed to assess the effect of ECMO on voriconazole exposure in a large patient population. METHODS: Critically ill patients from eight centers in four countries treated with voriconazole during ECMO support were included in this retrospective study. Voriconazole concentrations were collected in a period on ECMO and before/after ECMO treatment. Multivariate analyses were performed to evaluate the effect of ECMO on voriconazole exposure and to assess the impact of possible saturation of the circuit's binding sites over time. RESULTS: Sixty-nine patients and 337 samples (190 during and 147 before/after ECMO) were analyzed. Subtherapeutic concentrations (<2 mg/L) were observed in 56% of the samples during ECMO and 39% without ECMO (p = 0.80). The median trough concentration, for a similar daily dose, was 2.4 (1.2-4.7) mg/L under ECMO and 2.5 (1.4-3.9) mg/L without ECMO (p = 0.58). Extensive inter-and intrasubject variability were observed. Neither ECMO nor squared day of ECMO (saturation) were retained as significant covariates on voriconazole exposure. CONCLUSIONS: No significant ECMO-effect was observed on voriconazole exposure. A large proportion of patients had voriconazole subtherapeutic concentrations.

Mycoplasma genitalium acquisition and macrolide resistance after initiation of HIV pre-exposure prophylaxis in men who have sex with men.

OBJECTIVES: Recent evidence shows that patients using HIV pre-exposure prophylaxis (PrEP) have an increased rate of bacterial STIs, including syphilis, chlamydia and gonorrhoea. Our study aimed to describe the acquisition and the susceptibility for macrolides of Mycoplasma genitalium in men who have sex with men (MSM) on PrEP. METHODS: We studied all MSM who started PrEP in the AZ Sint-Jan Hospital Bruges from 1 June 2017 to 31 March 2019 with at least one follow-up visit. Patients were screened for M. genitalium and other STIs with pooled rectal swabs, pharyngeal swabs and first-voided urine, and blood samples at baseline and quarterly intervals after initiating PrEP. TaqMan Array Card technology was used to detect M. genitalium and determine macrolide-resistance mediating mutations in region V of the 23S rRNA gene (A2058G, A2059G, A2058C and others). Patients with an STI were treated based on a national guideline. RESULTS: 131 MSM (median age 40 years, range 20-79) were included in the study. The median follow-up time was 12 months (IQR 6.1-17). Baseline prevalence of M. genitalium was 6.9% and incidence rate after PrEP initiation was 28.8 per 100 person-years (95% CI 21.7 to 37.2), without significant differences in proportions between the first four quarterly intervals. All but one acquisitions were asymptomatic. Younger age and positivity for M. genitalium at baseline were significantly associated with incident M. genitalium acquisition. The observed proportion of macrolide resistance increased not significantly from 44% at baseline to 57%-86% after PrEP initiation. None of the 27 macrolide-resistant M. genitalium acquisitions could be linked to azithromycin exposure in the three preceding months. CONCLUSIONS: After initiation of PrEP, we found a stable incidence of almost exclusively asymptomatic M. genitalium. However, a non-significant trend of an increased percentage of macrolide-resistant strains was observed.

Augmented renal clearance in the critically ill: how to assess kidney function.

BACKGROUND: Augmented renal clearance in critically ill patients can result in underdosing of life-saving drugs, potentially leading to therapeutic failure. To detect this phenomenon, correct assessment of the kidney function is essential. Currently, little is known about the validity of mathematical formulas to estimate renal function in this subset of patients. OBJECTIVE: To evaluate the validity of different methods to estimate kidney function in critically ill patients with augmented renal clearance by comparing measured renal clearance with estimated clearance using different formulas. METHODS: An observational, retrospective, single-center study was conducted in a 34-bed surgical intensive care unit (SICU) of the University Hospitals Leuven, Leuven, Belgium. Adults admitted to the SICU in 2010 with a measured creatinine clearance (CrCl) of 120 mL/min or more (based on 24-hour urinary collection) were included. The measured clearance values were compared with estimated clearance values as calculated by the Cockcroft-Gault (CrCl(CG)) method and the reexpressed 4-variable Modification of Diet in Renal Disease estimated glomerular filtration rate (eGFR) formula. Spearman rank order correlation was performed to determine the relationship between measured and estimated clearances. Bland-Altman plots were evaluated to assess bias and limits of agreement between the 2 methods. RESULTS: Records on 1317 patients were screened. Augmented renal clearance was present in 390 patients. Spearman correlation showed fair correlation between measured and estimated clearances (r(s) = 0.343; p < 0.001 [CrCl(CG)] and r(s) = 0.290; p < 0.001 [eGFR]). Bias was -11.2 mL/min with limits of agreement (-131.7; 109.3 mL/min [CrCl(CG)]) and -19.9 mL/min with limits of agreement (-170.4; 130.7 mL/min [eGFR]). CONCLUSIONS: Estimated renal clearances, such as the eGFR estimated by the MDRD formula or CrCl estimated by CG, showed poor agreement with measured CrCl values in our critically ill population displaying augmented renal clearance. Clinicians should be cautious when interpreting kidney function based on estimating equations in this subset of patients. Instead, measured CrCl using urinary collection is recommended in patients suspected of displaying augmented renal clearance.