RPEM: Randomized Monte Carlo parametric expectation maximization algorithm

Inspired from quantum Monte Carlo, by sampling discrete and continuous variables at the same time using the Metropolis-Hastings algorithm, we present a novel, fast, and accurate high performance Monte Carlo Parametric Expectation Maximization (MCPEM) algorithm. We named it Randomized Parametric Expectation Maximization (RPEM). We compared RPEM with NONMEM's Importance Sampling Method (IMP), Monolix's Stochastic Approximation Expectation Maximization (SAEM), and Certara's Quasi-Random Parametric Expectation Maximization (QRPEM) for a realistic two-compartment voriconazole model with ordinary differential equations using simulated data. We show that RPEM is as fast and as accurate as the algorithms IMP, QRPEM, and SAEM for the voriconazole model in reconstructing the population parameters, for the normal and log-normal cases.

Comparison of daptomycin and glycopeptide efficacy and safety for the treatment of Gram-positive infections: a systematic review and meta-analysis

BACKGROUND

The indications of daptomycin have been extended to off-label indications including prosthesis-related infection, and bone and joint infection (BJI). However, efficacy and safety have not been thoroughly demonstrated compared with the standard of care. This systematic review and meta-analysis aimed to compare the treatment effect of daptomycin and glycopeptides for complicated infections.

MATERIALS AND METHODS

MEDLINE, Embase and Web of Science were searched for randomized controlled trials (RCTs) comparing daptomycin and standard of care for Gram-positive infections, published until 30 June 2021. The primary outcome was defined as all-cause mortality. Secondary outcomes were clinical and microbiological success. The main safety outcome was any severe adverse event (SAE) (grade  ≥3).

RESULTS

Overall, eight RCTs were included in the meta-analysis, totalling 1095 patients. Six (75%) were in complicated skin and soft-structure infections, one (12.5%) in bacteraemia and one (12.5%) in a BJI setting. Six RCTs used vancomycin as a comparator and two used either vancomycin or teicoplanin. All-cause mortality and clinical cure were not different between groups. The microbiological cure rate was superior in patients who received daptomycin [risk ratio (RR) = 1.17 (95% CI: 1.01-1.35)]. The risk of SAEs [RR = 0.57 (95% CI: 0.36-0.90)] was lower in the daptomycin arm.

CONCLUSIONS

While daptomycin is associated with a significantly lower risk of SAEs and a better microbiological eradication, substantial uncertainty remains about the best treatment strategy in the absence of good-quality evidence, especially in bacteraemia and endocarditis where further RCTs should be conducted.

What are the available online resources targeting psychosocial burden among stroke survivors and their informal caregivers: A scoping review

Background

After discharge home, stroke survivors and their informal caregivers face a significant lack of support and information which accentuates their psychosocial burden. Online resources might provide this support and address psychosocial needs, but existing online stroke programmes mainly target functional rehabilitation. We aimed to map the existing literature on online resources that have been evaluated in stroke rehabilitation and aimed at reducing psychosocial impact in stroke survivors and informal caregivers.

Methods

MEDLINE was searched (2010-2024) to identify studies investigating online resources targeting psychosocial health. Studies were selected and extracted independently by two reviewers. We described the content, use, and psychosocial impact of these interventions using a narrative approach.

Results

Eleven studies were included in the review, reporting 10 online resources (two studies relating to the same resource). Online resources were heterogeneous: eight information/resources websites, one mobile app, and one forum. Five online resources were dedicated to stroke survivors, four to stroke survivors and their informal caregivers, and one to informal caregivers. Two randomized controlled trials reported a significant decrease in depressive symptoms associated with the use of online resources. Stroke survivors and informal caregivers find online resources useful and acceptable to address their psychosocial needs.

Conclusions

Few online stroke resources have been designed and evaluated to support post-stroke psychosocial rehabilitation. Further larger-scale research needs to study the impact of these interventions on psychosocial recovery over time.

Daptomycin Exposure as a Risk Factor for Daptomycin-Induced Eosinophilic Pneumonia and Muscular Toxicity

BACKGROUND

High-dose daptomycin is increasingly used in patients with bone and joint infection (BJI). This raises concerns about a higher risk of adverse events (AEs), including daptomycin-induced eosinophilic pneumonia (DIEP) and myotoxicity. We aimed to examine pharmacokinetic and other potential determinants of DIEP and myotoxicity in patients with BJI receiving daptomycin.

METHODS

All patients receiving daptomycin for BJI were identified in a prospective cohort study. Cases were matched at a 1:3 ratio, with controls randomly selected from the same cohort. Bayesian estimation of the daptomycin daily area under the concentration-time curve over 24 hours (AUC24h) was performed with the Monolix software based on therapeutic drug monitoring (TDM) data. Demographic and biological data were also collected. Risk factors of AEs were analyzed using Cox proportional hazards model.

RESULTS

From 1130 patients followed over 7 years, 9 with DIEP, 26 with myotoxicity, and 106 controls were included in the final analysis. Daptomycin AUC24h, C-reactive protein, and serum protein levels were associated with the risk of AEs. The adjusted hazard ratio of DIEP or myotoxicity was 3.1 (95% confidence interval [CI], 1.48-6.5; P < .001) for daptomycin AUC24h > 939 mg/h/L, 9.8 (95% CI, 3.94-24.5; P < .001) for C-reactive protein > 21.6 mg/L, and 2.4 (95% CI, 1.02-5.65; P = .04) for serum protein <72 g/L.

CONCLUSIONS

We identified common determinants of DIEP and myotoxicity in patients with BJI. Because the risk of AEs was associated with daptomycin exposure, daptomycin TDM and model-informed precision dosing may help optimize the efficacy and safety of daptomycin treatment in this setting. A target AUC24h range of 666 to 939 mg/h/L is suggested.

621. Pharmacokinetics Determinant and Risk Factors of Daptomycin Induced Eosinophilic Pneumonia and Muscular Toxicity: A Survival Analysis in patients treated for Bone and Joint Infection

Background

Daptomycin prescription for patients suffering from Bone and Joint infections increased in recent years. However, the implication between daptomycin exposure, concomitant factor, and the occurrence of either daptomycin-induced eosinophilic pneumonia (DIEP) or CPK elevation is not clearly understood.

Methods

All patients treated for a bone and joint infection (BJI) between 2014 and 2021 were screened and classified into cases if they experienced a CPK elevation or DIEP. The controls were randomly selected at a 1:3 ratio within the same period of inclusion. Daptomycin levels were obtained from routine therapeutic drug monitoring. In addition, demographic and biology data were also obtained from the computerized file of patients. Those data were used to compute the area under the concentration-time curve (AUC) of daptomycin using a previously developed population pharmacokinetic model. Finally, a univariate analysis was performed and all data with a p-value &lt; 0.1 were included in the multivariate survival analysis using a proportional Cox hazard model.

Results

A total of 1130 patients were screened from which 16 patients with DIEP, 42 with CPK elevation, and 107 control were included in the final analysis. Age, CRP, Creatinine, Creatinine Clearance, Serum protein, AUC, and through concentrations were significantly different between case and controls. Summary of univariate analysis is available in table 1. After multivariate analysis, only 3 predictors remained significantly associated with the occurrence of DIEP or CPK elevation. The adjusted hazard ratio of developing DIEP of CPK elevation, were 3.1 (95% CI: 1.48 – 6.5, p &lt; 0.001) for a daptomycin AUC &gt; 939 mg.h/L, 9.8 (95% CI 3.94 – 24.5, p &lt; 0.001) for CRP &gt; 21.6mg/L and 2.4 (95% CI 1.02 – 5.65, p = 0.04] for Protein &lt; 72g/L. Survival curves are shown in figure1. Variable identified in the whole population remained significant in DIEP or CPK subgroup analyses. Table 1.Patients characteristics at time of inclusionFigure 1.Survival analysis of the whole population according to AUC and CRP levels.

Conclusion

The risk of experiencing DIEP or CPK elevation was greater in patients with an AUC0-24 above 939 mg.h/L and a CRP &gt; 21.6mg/L. Daptomycin Therapeutic drug monitoring should be performed and an AUC range of 666 to 939 mg.h/L should be targeted in order to maximize efficacy and minimize the risk of adverse events, especially for patients with an inflammatory syndrome.

Disclosures

All Authors: No reported disclosures.

Seventeen Cases of Daptomycin-Induced Eosinophilic Pneumonia in a Cohort of Patients Treated for Bone and Joint Infections: Proposal for a New Algorithm

BACKGROUND

Daptomycin is increasingly used in the treatment of bone and joint infections (BJIs) and may be responsible for daptomycin-induced eosinophilic pneumonia (DIEP), a potentially severe adverse drug reaction. The aim of this study was to describe DIEP in patients treated at a referral center for the management of BJI, and to revisit current definitions of this disease.

METHODS

Patients treated from 1 January 2012 to 31 March 2021 were included in a prospective cohort (NCT02817711), in which all potential serious adverse events are prospectively recorded. Patients diagnosed with DIEP were retrospectively analyzed using different definitions.

RESULTS

In a total of 4664 patients included in the cohort during the study period, 1021 patients (21.9%) received daptomycin, of whom 17 (1.7%) were diagnosed with DIEP. Most patients were male (n = 11 [64.7%]), and periprosthetic joint infection was the commonest BJI (n = 12 [70.6%]). Only 1 patient had bronchoalveolar lavage (BAL) eosinophil count ≥25%, while most patients had peripheral blood eosinophilia (n = 15 [88.2%]). Chest computed tomography (CT) was compatible with eosinophilic pneumonia in 13 of 14 cases (92.9%). All patients recovered upon discontinuation of daptomycin. Using the different definitions available, only a minority of cases fulfilled existing criteria for DIEP. We propose a new algorithm that includes specific CT scan signs, and systemic instead of BAL eosinophilia.

CONCLUSIONS

DIEP is a rare event that requires prompt discontinuation of the causative antibiotic. Current criteria to diagnose definite DIEP are too restrictive and not easily applicable in clinical practice. A new algorithm is proposed here (Lyon algorithm) to facilitate the early identification of DIEP.

Implementation of Model-Based Dose Adjustment of Tobramycin in Adult Patients with Cystic Fibrosis

Therapeutic drug monitoring (TDM) of tobramycin is widely performed in patients with cystic fibrosis (CF), but little is known about the value of model-informed precision dosing (MIPD) in this setting. We aim at reporting our experience with tobramycin MIPD in adult patients with CF. We analyzed data from adult patients with CF who received IV tobramycin and had model-guided TDM during the first year of implementation of MIPD. The predictive performance of a pharmacokinetic (PK) model was assessed. Observed maximal (Cmax) and minimal (Cmin) concentrations after initial dosing were compared with target values. We compared the initial doses and adjusted doses after model-based TDM, as well as renal function at the beginning and end of therapy. A total of 78 tobramycin courses were administered in 61 patients. After initial dosing set by physicians (mean, 9.2 ± 1.4 mg/kg), 68.8% of patients did not achieve the target Cmax ≥ 30 mg/L. The PK model fit the data very well, with a median absolute percentage error of 4.9%. MIPD was associated with a significant increase in tobramycin doses (p < 0.001) without significant change in renal function. Model-based dose suggestions were wellaccepted by the physicians and the expected target attainment for Cmax was 83%. To conclude, the implementation of MIPD was effective in changing prescribing practice and was not associated with nephrotoxic events in adult patients with CF.

Population Pharmacokinetics and Dosing Simulation of Vancomycin Administered by Continuous Injection in Critically Ill Patient

Background: Vancomycin is widely used for empirical antimicrobial therapy in critically ill patients with sepsis. Continuous infusion (CI) may provide more stable exposure than intermittent infusion, but optimal dosing remains challenging. The aims of this study were to perform population pharmacokinetic (PK) analysis of vancomycin administered by CI in intensive care unit (ICU) patients to identify optimal dosages. Methods: Patients who received vancomycin by CI with at least one measured concentration in our center over 16 months were included, including those under continuous renal replacement therapy (CRRT). Population PK was conducted and external validation of the final model was performed in a dataset from another center. Simulations were conducted with the final model to identify the optimal loading and maintenance doses for various stages of estimated creatinine clearance (CRCL) and in patients on CRRT. Target exposure was defined as daily AUC of 400-600 mg·h/L on the second day of therapy (AUC24-48 h). Results: A two-compartment model best described the data. Central volume of distribution was allometrically scaled to ideal body weight (IBW), whereas vancomycin clearance was influenced by CRRT and CRCL. Simulations performed with the final model suggested a loading dose of 27.5 mg/kg of IBW. The maintenance dose ranged from 17.5 to 30 mg/kg of IBW, depending on renal function. Overall, simulation showed that 55.8% (95% CI; 47-64%) of patients would achieve the target AUC with suggested dosages. Discussion: A PK model has been validated for vancomycin administered by CI in ICU patients, including patients under CRRT. Our model-informed precision dosing approach may help for early optimization of vancomycin exposure in such patients.

Population pharmacokinetics of daptomycin in patients with bone and joint infection: minimal effect of rifampicin co-administration and confirmation of a sex difference

BACKGROUND

Daptomycin is increasingly used in the treatment of bone and joint infection (BJI), but its pharmacokinetics (PK) and dosage requirements have not been thoroughly investigated in this indication. Daptomycin may be co-administered with rifampicin, which raises questions about a potential drug interaction.

OBJECTIVES

To investigate the population PK and dosage requirements of daptomycin in patients with BJI, and examine the influence of rifampicin co-administration.

METHODS

A population approach was used to analyse PK data from patients who received daptomycin in our regional reference for BJI. We examined the influence of available covariates, including rifampicin co-administration on daptomycin PK. Simulations performed with the final model investigated the influence of dosages and covariates on PTA for both efficacy and safety.

RESULTS

A total of 1303 daptomycin concentrations from 183 patients were analysed. A two-compartment model best described the data. Significant intra-individual variability was observed. Daptomycin clearance was influenced by renal function and sex, with females having a 26% lower typical clearance than males. Central volume of distribution (V1) was influenced by body weight, age, sex and rifampicin co-administration. Typical V1 was 11% lower in patients who were co-administered rifampicin. In PK/PD simulations, sex influenced the probability of AUC24/MIC target attainment, while rifampicin had a marginal effect.

CONCLUSIONS

A daptomycin dosage of 8 mg/kg/24 h in women and 10 mg/kg/24 h in men should optimize efficacy but may lead to excessive trough concentrations in many patients, especially in women. Therapeutic drug monitoring appears necessary for precision dosing of daptomycin.

Economic impact of clinical pharmaceutical activities in hospital wards: A systematic review

BACKGROUND

The positive impact of clinical pharmacy services (CPS) in improving clinical outcomes such as reduction of drug related problems is well demonstrated. Despite these results, the deployment of these activities is not systematically observed in the hospital setting.

OBJECTIVES

This systematic review first aimed to describe existing evidence regarding economic evaluation of ward-based CPS focusing on the entire treatment of a patient in a hospital setting. Secondly, the quality of economic evaluations of existing evidence was assessed.

METHODS

A comprehensive literature search was performed in PubMed/Medline, Science Direct and the NHS Economic Evaluation databases from January 2000 to March 2019. English or French language articles describing an economic evaluation of ward-based CPS on inpatients in hospital settings were included. Articles not describing a single study, dealing with a CPS not considering the entire medication regimen of the patient or presenting both inpatient and outpatient CPS were excluded. Selected articles were analyzed according to Drummond's check-list for assessing economic evaluations.

RESULTS

Forty-one studies were included. About one third were American publications. CPS implemented in ICU represented about half of the selected articles. Pharmacist-to-bed ratios varied according to countries and care unit type with the most favorable ratios in ICU and in American studies. Cost-avoidance was mostly used to express economic impact and ranged from €1579 to €3,089 328. Studies yielding the greater economic impact were conducted in the USA with implementation of full-time equivalents pharmacists or establishing of collaborative practice agreements. Only 6 articles dealt correctly with at least 7 of the 10 Drummond's checklist assessment criteria.

CONCLUSION

This review suggests that the existing evidence is not sufficient to conclude to a positive economic impact of CPS conducted according to clinical pharmacy guidelines. Funding resources, remuneration of clinical pharmacy activities and provision of standardized national clinical and economic databases appear to be essential evolutions to improve CPS development.