An initial dosing method for teicoplanin based on the area under the serum concentration time curve required for MRSA eradication

Teicoplanin in peritoneal dialysis: efficacy, safety, and pharmacological considerations

Peritoneal dialysis (PD) is a vital treatment modality for renal failure patients, facilitating the removal of excess fluid and unwanted substances. However, peritonitis, a significant complication experienced by PD patients, necessitates careful selection of antibiotics to ensure successful treatment. Commonly used antibiotics in PD patients, such as cephalosporins and glycopeptides like vancomycin, have been associated with undesirable side effects and high failure rates. In response to these challenges, teicoplanin, a novel glycopeptide antibiotic, has gained attention due to its similar range of activity to vancomycin, extended half-life, reduced side effects, and improved elimination. The objective of this study is to comprehensively review the efficacy, mechanism of action, adverse effects, and pharmacological benefits of teicoplanin in peritoneal dialysis patients. Our research involved an extensive review of 21 articles from reputable databases, including Google Scholar, PubMed, and ScienceDirect. The data extracted from these studies was meticulously evaluated to comprehensively understand teicoplanin's clinical profile in this specific patient population. Major findings of these studies are that glycopeptide-based regimens have higher cure rates over first-generation cephalosporins or fluoroquinolones, and teicoplanin demonstrated several advantages over vancomycin, such as a higher therapeutic index, good tolerance, longer half-life, lower rates of nephrotoxicity, improved elimination while being equally effective. Teicoplanin is typically administered to peritoneal dialysis patients with a loading dose of 400 mg, aiming to achieve a trough concentration of 10-15 mg/dl. Teicoplanin's improved tolerability and lack of regular serum level monitoring requirements make it a promising alternative to traditional antibiotics for clinical use.

Beyond One-Size-Fits-All: Tailoring Teicoplanin Regimens for Normal Renal Function Patients Using Population Pharmacokinetics and Monte Carlo Simulation

In patients with normal renal function, significant teicoplanin dose adjustments are often necessary. This study aimed to develop a population pharmacokinetic (PK) model for teicoplanin in healthy adults and use it to recommend optimal dosage regimens for patients with normal renal function. PK samples were obtained from 12 subjects and analyzed using a population approach. The derived parameters informed Monte Carlo simulations for dosing recommendations. The PK profile was best described using a three-compartment model, in which the estimated glomerular filtration rate calculated via the CKD-EPI equation and adjusted for body surface area was identified as a significant covariate affecting total clearance. For pathogens with a minimum inhibitory concentration of 1 mg/L, a loading dose (LD) of 14 mg/kg administered every 12 h for four doses, followed by a maintenance dose (MD) of 16 mg/kg administered every 24 h, is recommended. These findings indicate the need for dosage adjustments, such as increasing the LD and MD or decreasing the dosing interval of MD in patients with normal renal function. Because of the long half-life of teicoplanin and the requirement for long-term administration, therapeutic drug monitoring at strategic intervals is important to avoid nephrotoxicity associated with elevated trough concentrations.

Individualized antibiotic dosage regimens for patients with augmented renal clearance

Objectives: Augmented renal clearance (ARC) is a state of enhanced renal function commonly observed in 30%-65% of critically ill patients despite normal serum creatinine levels. Using unadjusted standard dosing regimens of renally eliminated drugs in ARC patients often leads to subtherapeutic concentrations, poor clinical outcomes, and the emergence of multidrug-resistant bacteria. We summarized pharmaceutical, pharmacokinetic, and pharmacodynamic research on the definition, underlying mechanisms, and risk factors of ARC to guide individualized dosing of antibiotics and various strategies for optimizing outcomes. Methods: We searched for articles between 2010 and 2022 in the MEDLINE database about ARC patients and antibiotics and further provided individualized antibiotic dosage regimens for patients with ARC. Results: 25 antibiotic dosage regimens for patients with ARC and various strategies for optimization of outcomes, such as extended infusion time, continuous infusion, increased dosage, and combination regimens, were summarized according to previous research. Conclusion: ARC patients, especially critically ill patients, need to make individualized adjustments to antibiotics, including dose, frequency, and method of administration. Further comprehensive research is required to determine ARC staging, expand the range of recommended antibiotics, and establish individualized dosing guidelines for ARC patients.

Target Therapeutic Ranges of Anti-MRSA Drugs, Linezolid, Tedizolid and Daptomycin, and the Necessity of TDM

The target therapeutic ranges of vancomycin, teicoplanin, and arbekacin have been determined, and therapeutic drug monitoring (TDM) is performed in clinical practice. However, TDM is not obligatory for daptomycin, linezolid, or tedizolid. In this study, we examined whether TDM will be necessary for these 3 drugs in the future. There was no significant difference in therapeutic effects on acute bacterial skin and skin structure infection between linezolid and tedizolid by meta-analysis. Concerning the therapeutic effects on pneumonia, the rate of effectiveness after treatment with tedizolid was significantly lower than with linezolid. With respect to safety, the incidences of gastrointestinal adverse events and blood/lymphatic system disorders related to tedizolid were significantly lower than those related to linezolid. Linezolid exhibits potent therapeutic effects on pneumonia, but the appearance of adverse reactions is indicated as a problem. There was a dose-dependent decrease in the platelet count, and the target trough concentration (C_trough) was estimated to be 4-6 or 2-7 µg/mL in accordance with the patient's condition. The efficacy of linezolid may be obtained while minimizing the appearance of adverse reactions by performing TDM. The target therapeutic range of tedizolid cannot be achieved in immunocompromised or severe patients. Therefore, we concluded that TDM was unnecessary, considering step-down therapy with oral drugs, use in non-severe patients, and high-level safety. Concerning daptomycin, high-dose administration is necessary to achieve an area under the curve (AUC) of ≥666 as an index of efficacy. To secure its safety, C_trough (<20 µg/mL) monitoring is important. Therefore, TDM is necessary.

Pharmacokinetics and pharmacodynamics of peptide antibiotics

Antimicrobial resistance is a major global health challenge. As few new efficacious antibiotics will become available in the near future, peptide antibiotics continue to be major therapeutic options for treating infections caused by multidrug-resistant pathogens. Rational use of antibiotics requires optimisation of the pharmacokinetics and pharmacodynamics for the treatment of different types of infections. Toxicodynamics must also be considered to improve the safety of antibiotic use and, where appropriate, to guide therapeutic drug monitoring. This review focuses on the pharmacokinetics/pharmacodynamics/toxicodynamics of peptide antibiotics against multidrug-resistant Gram-negative and Gram-positive pathogens. Optimising antibiotic exposure at the infection site is essential for improving their efficacy and minimising emergence of resistance.

Therapeutic Drug Monitoring of Antibiotics: Defining the Therapeutic Range

PURPOSE

In the present narrative review, the authors aimed to discuss the relationship between the pharmacokinetic/pharmacodynamic (PK/PD) of antibiotics and clinical response (including efficacy and toxicity). In addition, this review describes how this relationship can be applied to define the therapeutic range of a particular antibiotic (or antibiotic class) for therapeutic drug monitoring (TDM).

METHODS

Relevant clinical studies that examined the relationship between PK/PD of antibiotics and clinical response (efficacy and response) were reviewed. The review (performed for studies published in English up to September 2021) assessed only commonly used antibiotics (or antibiotic classes), including aminoglycosides, beta-lactam antibiotics, daptomycin, fluoroquinolones, glycopeptides (teicoplanin and vancomycin), and linezolid. The best currently available evidence was used to define the therapeutic range for these antibiotics.

RESULTS

The therapeutic range associated with maximal clinical efficacy and minimal toxicity is available for commonly used antibiotics, and these values can be implemented when TDM for antibiotics is performed. Additional data are needed to clarify the relationship between PK/PD indices and the development of antibiotic resistance.

CONCLUSIONS

TDM should only be regarded as a means to achieve the main goal of providing safe and effective antibiotic therapy for all patients. The next critical step is to define exposures that can prevent the development of antibiotic resistance and include these exposures as therapeutic drug monitoring targets.

Clinical practice guidelines for therapeutic drug monitoring of teicoplanin: a consensus review by the Japanese Society of Chemotherapy and the Japanese Society of Therapeutic Drug Monitoring

Background

Owing to its low risk of adverse effects, teicoplanin has been extensively used in patients with infections caused by MRSA. To promote the better management of patients receiving teicoplanin, we have updated the guidelines for therapeutic drug monitoring (TDM).

Methods

The guidelines were developed by a committee following the methodology handbook published by the Japanese Medical Information Distribution Service. Nine clinical questions were selected. The committee conducted a systematic review and meta-analysis to establish evidence-based recommendations for the target trough concentration (C_min). An initial electronic database search returned 515 articles, and 97 articles qualified for a full review. Four and five studies were included for the efficacy evaluation of cut-off C_min values of 15 and 20 mg/L, respectively.

Results

Compared with C_min < 15 mg/L, a target C_min value of 15–30 mg/L resulted in increased clinical efficacy in patients with non-complicated MRSA infections (OR = 2.68; 95% CI = 1.14–6.32) without an increase in adverse effects. Although there was insufficient evidence, target C_min values of 20–40 mg/L were suggested in patients with complicated or serious MRSA infections. A 3 day loading regimen followed by maintenance treatment according to renal function was recommended to achieve the target trough concentrations. Because of the prolonged half-life of teicoplanin, measurement of the C_min value on Day 4 before reaching steady state was recommended.

Conclusions

The new guideline recommendations indicate the target C_min value for TDM and the dosage regimen to achieve this concentration and suggest practices for specific subpopulations.

Enhanced loading dose of teicoplanin for three days is required to achieve a target trough concentration of 20 μg/mL in patients receiving continuous venovenous haemodiafiltration with a low flow rate

INTRODUCTION

Because of its lower risk of renal toxicity than vancomycin, teicoplanin is the preferred treatment for methicillin-resistant Staphylococcus aureus infection in patients undergoing continuous venovenous haemodiafiltration (CVVHDF) in whom renal function is expected to recover. The dosing regimen for achieving a trough concentration (C_min) of ≥20 μg/mL remains unclear in patients on CVVHDF using the low flow rate adopted in Japan.

METHODS

The study was conducted in patients undergoing CVVHDF with a flow rate of <20 mg/kg/h who were treated with teicoplanin. We adopted three loading dose regimens for the initial 3 days: the conventional regimen, a high-dose regimen (four doses of 10 mg/kg), and an enhanced regimen (four doses of 12 mg/kg). The initial C_min was obtained at 72 h after the first dose.

RESULTS

Overall, 60 patients were eligible for study inclusion. The proportion of patients achieving the C_min target was significantly higher for the enhanced regimen than for the high-dose regimen (52.9% versus 8.3%, p = 0.003). In multivariate analysis, the enhanced regimen (odds ratio [OR] = 39.93, 95% confidence interval [CI] = 5.03-317.17) and hypoalbuminaemia (OR = 0.04, 95% CI = 0.01-0.44) were independent predictors of the achievement of C_min ≥ 20 μg/mL.

CONCLUSIONS

An enhanced teicoplanin regimen was proposed to treat complicated or invasive infections by methicillin-resistant Staphylococcus aureus in patients receiving CVVHDF even with a low flow rate.

Physiologically Based Pharmacokinetic Modeling and Dose Adjustment of Teicoplanin in Pediatric Patients With Renal Impairment

The pharmacokinetics of teicoplanin differs in children as compared with adults, and especially in renally impaired pediatric patients. Inappropriate empirical antibacterial therapy may lead to treatment-related antibacterial resistance and increased toxicity, making adjustment of the dosage regimen essential. In the present study, physiologically based pharmacokinetic (PBPK) models were developed to define the appropriate dosage regimen for pediatric patients with differing renal function. Our PBPK models accurately predicted teicoplanin exposures in both adult and pediatric subjects after single and multiple intravenous infusions, with a <1.36-fold error between predicted and observed data, and all observed data were within minimal and maximal data of the corresponding population simulation. The area under the plasma concentration-time curve was predicted to increase 1.25-fold, 1.95-fold, and 2.82-fold in pediatric patients with mild, moderate, and severe renal impairment, respectively, relative to that of healthy children. Subsequently, the results of Monte Carlo simulations indicated that the recommended dosing of 12, 9.5, 6, and 4 mg/kg at 12-hour intervals would be appropriate in pediatric patients with normal renal function and in those with mild, moderate, and severe renal impairment, respectively, at a susceptible minimum inhibitory concentration <2 mg/L. In conclusion, our PBPK model with an incorporated Monte Carlo simulation can provide improved guidance on dosing in pediatric patients with differing renal function and provide a basis for precision therapy with teicoplanin.

Teicoplanin Therapeutic Drug Monitoring and Treatment Outcomes in Children With Gram-Positive Infections

This is a retrospective audit of teicoplanin dosing, drug-level monitoring, and outcomes in 29 children who received 31 courses of teicoplanin. Our study of noncritically ill children showed that the majority (35/43, 81%) of trough concentrations were within the therapeutic range (10-30 mg/L) contrasting previous studies in children. Overall, 21 of the 24 (88%) children with Gram-positive infections achieved cure.

Evaluation of a thrice weekly administration of teicoplanin in the outpatient setting: a retrospective observational multicentre study

Introduction

The glycopeptide teicoplanin is commonly utilized to facilitate outpatient parenteral antimicrobial therapy (OPAT). Licensed for once daily maintenance dosing, teicoplanin’s long half-life allows for less frequent dosing (e.g. thrice weekly) following successful loading. This service evaluation reviews the safety and effectiveness of a novel thrice weekly teicoplanin dosing regimen.

Methods

A retrospective, observational study was conducted at Chelsea and Westminster Hospital (March 2018 to July 2020), evaluating trough serum teicoplanin concentrations for patients receiving >5 days of teicoplanin in the OPAT setting. Teicoplanin dosing and administration (once daily versus thrice weekly), clinical outcomes and therapeutic levels were analysed for all patients. The project was registered with clinical governance locally.

Results

A total of 82 patients treated with teicoplanin in the OPAT service were included; 53/82 receiving thrice weekly and 29/82 receiving once daily dosing. Mean teicoplanin trough levels were similar in both groups (26.2 mg/L and 25.8 mg/L in once daily and thrice weekly groups, P = 0.8895). High clinical success rates were recorded in both groups (25/29 [86.2%] versus 50/53 [94.3%]). No correlation with clinical outcomes and initial teicoplanin serum levels was identified. Normal renal function (>90 mL/min) was associated with lower teicoplanin serum concentrations (mean [±SD] 21.4 mg/L [±10.1] versus 29.7 mg/L [±14], P = 0.0178) in the thrice weekly dosed group but not with the once daily dosed group (mean [±SD] 28.2 mg/L [±9.4] versus 23.7 mg/L [±9.9], P = 0.2201).

Conclusions

This study supports thrice weekly teicoplanin as a convenient and effective OPAT for administration in the OPAT setting. Therapeutic drug monitoring is advised to adjust for intra-patient variability.

Population Pharmacokinetics and Model-Based Dosing Optimization of Teicoplanin in Pediatric Patients

Objectives: The pharmacokinetics (PK) of teicoplanin differs in children compared with adults. Our aim was to determine the PK of teicoplanin in an Asian pediatric population and to optimize dosage regimens. Methods: This was a retrospective PK study and all the data were collected from hospitalized children. We developed a population PK model using sparse data, and Monte Carlo simulation was used to assess the ability of standard teicoplanin regimen and other different dosage regimens. The optimal dosing regimens were defined as achieving the target trough concentration (C _min) of 10 mg/L and pharmacokinetic/pharmacodynamic (PK/PD, [AUC₂₄/MIC]) of 125 for moderate infection. For severe infection, the optimal dosing regimens were defined as achieving the target 15 mg/L and AUC₂₄/MIC of 345. Results: 159 children were included and 1.5 samples/children on average were provided. Estimated clearance of teicoplanin was 0.694 L/h (0.784/L/h/70 kg) and volume of distribution was 1.39 L. Teicoplanin standard loading dose was adequate for moderate infection, while 13 mg/kg was needed for severer infection. With standard maintenance doses, both patients with moderate and severe infection failed to achieve the target C _min. 12 and 16 mg/kg/day were required to achieve a C _min ≥ 10 and 15 mg/L, respectively. However, standard maintenance dose was adequate to achieve AUC₂₄/MIC ≥ 125 for moderate infection, and 12 mg/kg/day was needed to achieve AUC₂₄/MIC ≥ 345 for severe infection. Lower weight and serum creatinine were associated with higher dose. Conclusion: Optimal doses based on the target C _min were higher than that based on the PK/PD target. To achieve the C _min and PK/PD targets simultaneously, a standard loading dose was adequate for moderate infection based on simulation, while dosing higher than standard doses were required in other situation. Further clinical studies with rich sampling from children is required to confirm our findings.

Pharmacokinetic/pharmacodynamic evaluation of teicoplanin against Staphylococcus aureus in a murine thigh infection model

OBJECTIVES

Pharmacokinetic/pharmacodynamic (PK/PD) analysis using murine infection models is a well-established methodology for optimising antimicrobial therapy. Therefore, we investigated the PK/PD indices of teicoplanin againstStaphylococcus aureus using a murine thigh infection model.

METHODS

Mice were rendered neutropenic by administration of a two-step dosing of cyclophosphamide. Then, isolates of methicillin-susceptibleS. aureus (MSSA) or methicillin-resistant S. aureus (MRSA) were inoculated into the thighs of neutropenic mice. PK/PD analyses were performed by non-linear least-squared regression using the MULTI program.

RESULTS

Target values offC_max/MIC (r² = 0.94) of teicoplanin for static effect and 1 log₁₀ kill against MSSA were 4.44 and 15.44, respectively. Target values of fAUC₂₄/MIC (r² = 0.92) of teicoplanin for static effect and 1 log₁₀ kill against MSSA were 30.4 and 70.56, respectively. Target values of fC_max/MIC (r² = 0.91) of teicoplanin for static effect and 1 log₁₀ kill against MRSA were 8.92 and 14.16, respectively. Target values of fAUC₂₄/MIC (r² = 0.92) of teicoplanin for static effect and 1 log₁₀ kill against MRSA were 54.8 and 76.4, respectively.

CONCLUSION

These results suggest thatfC_max/MIC and fAUC₂₄/MIC are useful PK/PD indices of teicoplanin against MSSA and MRSA.

Population Pharmacokinetics of Unbound and Total Teicoplanin in Critically Ill Pediatric Patients

BACKGROUND AND OBJECTIVES

Teicoplanin is a highly protein-bound antibiotic, increasingly used to treat serious Gram-positive infections in critically ill children. Maturational and pathophysiological intensive care unit-related changes often lead to altered pharmacokinetics. In this study, the objectives were to develop a pediatric population-pharmacokinetic model of unbound and total teicoplanin concentrations, to investigate the impact of plasma albumin levels and renal function on teicoplanin pharmacokinetics, and to evaluate the efficacy of the current weight-based dosing regimen.

METHODS

An observational pharmacokinetic study was performed and blood samples were collected for quantification of unbound and total concentrations of teicoplanin after the first dose and in assumed steady-state conditions. A population-pharmacokinetic analysis was conducted using a standard sequential approach and Monte Carlo simulations were performed for a probability of target attainment analysis using previously published pharmacokinetic-pharmacodynamic targets.

RESULTS

A two-compartment model with allometric scaling of pharmacokinetic parameters and non-linear plasma protein binding best described the data. Neither the inclusion of albumin nor the renal function significantly improved the model and no other covariates were supported for inclusion in the final model. The probability of target attainment analysis showed that the standard dosing regimen does not satisfactory attain the majority of the proposed targets.

CONCLUSIONS

We successfully characterized the pharmacokinetics of unbound and total teicoplanin in critically ill pediatric patients. The highly variable unbound fraction of teicoplanin could not be predicted using albumin levels, which may support the use of therapeutic drug monitoring of unbound concentrations. Poor target attainment was shown for the most commonly used dosing regimen, regardless of the pharmacokinetic-pharmacodynamic target evaluated.

Population Pharmacokinetics of Teicoplanin in Preterm and Term Neonates: Is It Time for a New Dosing Regimen?

Our objective was to develop a population pharmacokinetic (PK) model in order to evaluate the currently recommended dosing regimen in term and preterm neonates. By using an optimal design approach, a prospective PK study was designed and implemented in 60 neonates with postmenstrual ages (PMA) of 26 to 43 weeks. A loading dose of 16 mg/kg was administered at day 1, followed by a maintenance dose of 8 mg/kg daily. Plasma concentrations were quantified by high-pressure liquid chromatography-mass spectrometry. Population PK (popPK) analysis was performed using NONMEM software. Monte-Carlo (MC) simulations were performed to evaluate currently recommended dosing based on a pharmacodynamic index of area under the concentration-time curve (AUC)/MIC ratio of ≥400. A two-compartment model with linear elimination best described the data by the following equations: clearance (CL) = 0.0227 × (weight [wt]/1,765)^0.75 × (estimated creatinine clearance [eCRCL]/22)^0.672, central compartment volume of distribution (V1) = 0.283 (wt/1,765), intercompartmental clearance (Q) = 0.151 (wt/1,765)^0.75, and peripheral compartment volume (V2) = 0.541 (wt/1,765). The interindividual variability estimates for CL, V1, and V2 were 36.5%, 45.7%, and 51.4%, respectively. Current weight (wt) and estimated creatinine clearance (eCRCL) significantly explained the observed variability. MC simulation demonstrated that, with the current dosing regimen, an AUC/MIC ratio of ≥400 was reached by only 68.5% of neonates with wt of <1 kg when the MIC was equal to 1 mg/kg, versus 82.2%, 89.7%, and 92.7% of neonates with wt of 1 to <2, 2 to <3, or ≥3 kg, respectively. Augmentation of a maintenance dose up to 10 or 11 mg/kg for preterm neonates with wt of 1 to <2 or <1 kg, respectively, increases the probability of reaching the therapeutic target; the recommended doses seem to be adequate for neonates with wt of ≥2 kg. Teicoplanin PK are variable in neonates, with wt and eCRCL having the most significant impact. Neonates with wt of <2 kg need higher doses, especially for Staphylococcus spp. with an MIC value of ≥1 mg/liter.

Pharmacodynamics of teicoplanin against MRSA

Objectives

The overall study aim was to identify the relevant preclinical teicoplanin pharmacokinetic (PK)/pharmacodynamic (PD) indices to predict efficacy and suppression of resistance in MRSA infection.

Methods

A hollow-fibre infection model and a neutropenic murine thigh infection model were developed. The PK/PD data generated were modelled using a non-parametric population modelling approach with Pmetrics. The posterior Bayesian estimates derived were used to study the exposure-effect relationships. Monte Carlo simulations from previously developed population PK models in adults and children were conducted to explore the probability of target attainment (PTA) for teicoplanin dosage regimens against the current EUCAST WT susceptibility range.

Results

There was a concentration-dependent activity of teicoplanin in both the in vitro and in vivo models. A total in vivo AUC/MIC of 610.4 (total AUC of 305.2 mg·h/L) for an MRSA strain with an MIC of 0.5 mg/L was needed for efficacy (2 log10 cell kill) against a total bacterial population. A total AUC/MIC ratio of ∼1500 (total AUC of ∼750 mg·h/L) was needed to suppress the emergence of resistance. The PTA analyses showed that adult and paediatric patients receiving a standard regimen were only successfully treated for the in vivo bactericidal target if the MIC was ≤0.125 mg/L in adults and ≤0.064 mg/L in children.

Conclusions

This study improves our understanding of teicoplanin PD against MRSA and defines an in vivo AUC/MIC target for efficacy and suppression of resistance. Additional studies are needed to further corroborate the PK/PD index in a variety of infection models and in patients.

Tools for the Individualized Therapy of Teicoplanin for Neonates and Children

The aim of this study was to develop a population pharmacokinetic (PK) model for teicoplanin across childhood age ranges to be used as Bayesian prior information in the software constructed for individualized therapy. We developed a nonparametric population model fitted to PK data from neonates, infants, and older children. We then implemented this model in the BestDose multiple-model Bayesian adaptive control algorithm to show its clinical utility. It was used to predict the dosages required to achieve optimal teicoplanin predose targets (15 mg/liter) from day 3 of therapy. We performed individual simulations for an infant and a child from the original population, who provided early first dosing interval concentration-time data. An allometric model that used weight as a measure of size and that also incorporated renal function using the estimated glomerular filtration rate (eGFR), or the ratio of postnatal age (PNA) to serum creatinine concentration (SCr) for infants <3 months old, best described the data. The median population PK parameters were as follows: elimination rate constant (Ke) = 0.03 · (wt/70)^−0.25 · Renal (h⁻¹); V = 19.5 · (wt/70) (liters); Renal = eGFR^0.07 (ml/min/1.73 m²), or Renal = PNA/SCr (μmol/liter). Increased teicoplanin dosages and alternative administration techniques (extended infusions and fractionated multiple dosing) were required in order to achieve the targets safely by day 3 in simulated cases. The software was able to predict individual measured concentrations and the dosages and administration techniques required to achieve the desired target concentrations early in therapy. Prospective evaluation is now needed in order to ensure that this individualized teicoplanin therapy approach is applicable in the clinical setting. (This study has been registered in the European Union Clinical Trials Register under EudraCT no. 2012-005738-12.)

Optimal teicoplanin dosage regimens for methicillin-resistant Staphylococcus aureus infections in endocarditis patients and renal failure patients

This study aimed to assess whether traditional initial loading and maintenance doses of teicoplanin were appropriate in endocarditis and renal failure patients with methicillin-resistant Staphylococcus aureus (MRSA) infections and to recommend optimal dosage regimens. Pharmacokinetic parameters and physicochemical properties of teicoplanin were performed to develop pharmacokinetic models using GastroPlus^TM. Concentration-time curves of teicoplanin in endocarditis and renal failure patients with MRSA infections were simulated by changing clearance (CL) and volume of distribution of the central compartment (V_c). Different teicoplanin dosage regimens were assessed according to the target trough concentration, and optimal teicoplanin dosage regimens were recommended. Dosage regimen of four teicoplanin doses of 6 mg/kg q12 h followed by 6 mg/kg qd is recommended for renal failure patients infected by MRSA. And optimal dosage regimen is five teicoplanin doses of 15 mg/kg q12 h followed by doses of 12 mg/kg qd for endocarditis patients infected by MRSA.

Population pharmacokinetics of teicoplanin and attainment of pharmacokinetic/pharmacodynamic targets in adult patients with haematological malignancy

OBJECTIVES

To describe the population pharmacokinetics of teicoplanin in adult patients with haematological malignancies receiving higher than standard doses, and to perform Monte Carlo simulations to determine dosing regimens associated with optimal teicoplanin concentrations.

METHODS

This was a hospital-based clinical trial (EudraCT 2013-004535-72). Nine blood samples were collected on Day 3, plus single trough samples on Days 7 and 10, and 24 and 48 hours after the last dose. Teicoplanin minimum inhibitory concentrations were determined for Gram-positive isolates from study patients. Population pharmacokinetic analyses and Monte Carlo dosing simulations were undertaken using Pmetrics.

RESULTS

Thirty adult haematological malignancy patients were recruited with a mean (SD) loading dose, age, total body weight, and creatinine clearance of 9.5 (1.9) mg/kg, 63 (12) years, 69.1 (15.8) kg, and 72 (41) mL/min, respectively. A three-compartment linear pharmacokinetic model best described the teicoplanin concentration data. Covariates supported for inclusion in the final model were creatinine clearance for clearance and total body weight for volume of the central compartment. The median (IQR) area under the concentration-time curve from 48 to 72 hours (AUC_48-72h) was 679 (319) mg.h/L. There was a strong correlation between the AUC_48-72h and trough concentration at 72 hours (Pearson correlation coefficient 0.957, p <0.001). Dosing simulations showed that administration of five loading doses at 12-hourly intervals, stratified by total body weight and creatinine clearance, increased the probability of achieving target concentrations within 72 hours.

CONCLUSIONS

To increase the number of patients achieving optimal teicoplanin concentrations an individualized dosing approach, based on body weight and creatinine clearance, is recommended.

Pharmacokinetic/pharmacodynamic analysis of teicoplanin in patients with MRSA infections

Background

Teicoplanin is a glycopeptide antibiotic that has been used to treat serious, invasive infections caused by Gram-positive bacteria. The area under the drug concentration–time curve (AUC)/minimum inhibitory concentration (MIC) was identified as a pharmacokinetic–pharmacodynamic (PK–PD) parameter of glycopeptide antibiotics that correlated with bacteriological responses and clinical outcomes. Although optimized dosing regimens based on PK–PD are needed, a PK–PD analysis of teicoplanin against methicillin-resistant Staphylococcus aureus (MRSA) infections has not yet been performed. Thus, this study examined patients with MRSA infections, who were administered with teicoplanin in order to determine the target AUC/MIC ratio.

Methods

This study retrospectively assessed data obtained as part of our routine therapeutic drug monitoring (TDM) of teicoplanin therapy in 46 patients with MRSA infections at Kagoshima University Hospital. Serum concentrations of teicoplanin were determined using a fluorescence polarization immunoassay system and used for a Bayesian PK estimation to estimate AUC for 24 hours (AUC₂₄). The MIC value for teicoplanin was determined using a standardized agar dilution method. The effects of teicoplanin were evaluated in terms of bacteriological responses by a quantitative assessment.

Results

The estimated AUC₂₄/MIC ratios with and without bacteriological responses were 926.6±425.2 µg·h/mL (n=34) and 642.2±193.9 µg·h/mL, respectively (n=12; P<0.05). On the basis of a logistic regression analysis, AUC₂₄/MIC ratios of 500 µg·h/mL, 700 µg·h/mL, and 900 µg·h/mL gave probabilities of treatment success of 0.50, 0.72, and 0.87, respectively. Furthermore, using the Kaplan–Meier curve analysis, an AUC₂₄/MIC ratio of ≥900 led to a significantly stronger bacteriological response than an AUC₂₄/MIC ratio of <900.

Conclusion

These results suggest that an AUC₂₄/MIC ratio of ≥900 µg·h/mL is required to ensure a sufficient bacteriological response.

Population pharmacokinetics and dosing optimization of teicoplanin in children with malignant haematological disease

AIM

Children with haematological malignancy represent an identified subgroup of the paediatric population with specific pharmacokinetic parameters. In these patients, inadequate empirical antibacterial therapy may result in infection-related morbidity and increased mortality, making optimization of the dosing regimen essential. As paediatric data are limited, our aim was to evaluate the population pharmacokinetics of teicoplanin in order to define the appropriate dosing regimen in this high risk population.

METHODS

The current dose of teicoplanin was evaluated in children with haematological malignancy. Population pharmacokinetics of teicoplanin were analyzed using nonmem software. The dosing regimen was optimized based on the final model.

RESULTS

Eighty-five children (age range 0.5 to 16.9 years) were included. Therapeutic drug monitoring and opportunistic samples (n = 143) were available for analysis. With the current recommended dose of 10 mg kg(-1) day(-1) , 41 children (48%) had sub-therapeutic steady-state trough concentrations (Css,min <10 mg l(-1) ). A two compartment pharmacokinetic model with first order elimination was developed. Systematic covariate analysis identified that bodyweight (size) and creatinine clearance significantly influenced teicoplanin clearance. The model was validated internally. Its predictive performance was further confirmed in an external validation. In order to reach the target AUC of 750 mg l(-1)  h 18 mg kg(-1) was required for infants, 14 mg kg(-1) for children and 12 mg kg(-1) for adolescents. A patient-tailored dose regimen was further developed and reduced variability in AUC and Css,min values compared with the mg kg(-1) basis dose, making the modelling approach an important tool for dosing individualization.

CONCLUSIONS

This first population pharmacokinetic study of teicoplanin in children with haematological malignancy provided evidence-based support to individualize teicoplanin therapy in this vulnerable population.

Population pharmacokinetics of teicoplanin in children

Teicoplanin is frequently administered to treat Gram-positive infections in pediatric patients. However, not enough is known about the pharmacokinetics (PK) of teicoplanin in children to justify the optimal dosing regimen. The aim of this study was to determine the population PK of teicoplanin in children and evaluate the current dosage regimens. A PK hospital-based study was conducted. Current dosage recommendations were used for children up to 16 years of age. Thirty-nine children were recruited. Serum samples were collected at the first dose interval (1, 3, 6, and 24 h) and at steady state. A standard 2-compartment PK model was developed, followed by structural models that incorporated weight. Weight was allowed to affect clearance (CL) using linear and allometric scaling terms. The linear model best accounted for the observed data and was subsequently chosen for Monte Carlo simulations. The PK parameter medians/means (standard deviation [SD]) were as follows: CL, [0.019/0.023 (0.01)] × weight liters/h/kg of body weight; volume, 2.282/4.138 liters (4.14 liters); first-order rate constant from the central to peripheral compartment (Kcp), 0.474/3.876 h(-1) (8.16 h(-1)); and first-order rate constant from peripheral to central compartment (Kpc), 0.292/3.994 h(-1) (8.93 h(-1)). The percentage of patients with a minimum concentration of drug in serum (Cmin) of <10 mg/liter was 53.85%. The median/mean (SD) total population area under the concentration-time curve (AUC) was 619/527.05 mg · h/liter (166.03 mg · h/liter). Based on Monte Carlo simulations, only 30.04% (median AUC, 507.04 mg · h/liter), 44.88% (494.1 mg · h/liter), and 60.54% (452.03 mg · h/liter) of patients weighing 50, 25, and 10 kg, respectively, attained trough concentrations of >10 mg/liter by day 4 of treatment. The teicoplanin population PK is highly variable in children, with a wider AUC distribution spread than for adults. Therapeutic drug monitoring should be a routine requirement to minimize suboptimal concentrations. (This trial has been registered in the European Clinical Trials Database Registry [EudraCT] under registration number 2012-005738-12.).

Daptomycin approved in Japan for the treatment of methicillin-resistant Staphylococcus aureus

Daptomycin is a lipoglycopeptide antibacterial drug that is rapidly bactericidal for methicillin-resistant Staphylococcus aureus (MRSA) infection and has antibiotic activity against a wide range of Gram-positive organisms. It has been approved by the Ministry of Health, Labor and Welfare in Japan for the treatment for bacteremia, right-sided endocarditis, and skin and skin-structure infections, such as necrotizing fasciitis, due to MRSA on the basis of a Phase III trial conducted in Japan since July, 2011. In Japanese Phase I and III trials, daptomycin therapy given at 4 mg/kg and 6 mg/kg once per day was well tolerated and effective as standard therapy for the treatment of acute bacterial skin and skin-structure infections and bacteremia caused by MRSA, but side effects remain to be evaluated in large-scale trials.