Expert Opinion on Dose Regimen and Therapeutic Drug Monitoring for Long-Term Use of Dalbavancin: Expert Review Panel

Liquid Chromatography-Tandem Mass Spectrometry Method for Therapeutic Drug Monitoring of Dalbavancin in Plasma of Pediatric and Young Adult Patients

BACKGROUND

Dalbavancin, an antimicrobial lipoglycopeptide, is authorized in Europe for treating acute bacterial infections of the skin and skin structures in adults and pediatric patients aged 3 months and older. However, off-label dosing regimens have been proposed for various indications beyond acute bacterial infections of the skin and skin structures. This study presents a novel bioanalytical method using liquid chromatography-tandem mass spectrometry to quantify dalbavancin in low-volume plasma samples (50 μL).

METHODS

The method underwent validation in accordance with international guidelines for bioanalytical method validation and was applied to 9 clinical samples obtained from pediatric and young adult patients undergoing dalbavancin therapy. Liquid chromatography-tandem mass spectrometry analyses were conducted at the G. Gaslini Institute in Genoa, Italy, utilizing an Ultimate 3000 ultra high performance liquid chromatography system coupled to a TSQ Quantiva Triple Quadrupole system (Thermo Fisher Scientific, Milan, Italy). The analytical procedure involved the addition of deuterated dalbavancin as internal standard and a rapid extraction from 50 µL of human plasma, followed by chromatographic separation on a Thermo Scientific Accucore Polar Premium column. Accurate quantification of the analyte was achieved through multiple reaction monitoring detection.

RESULTS

The assay exhibited linearity within the concentration range of 0.66-400 mcg/mL in plasma, demonstrating accuracy and reproducibility in the absence of matrix effects. Stability testing was conducted on both quality controls and real samples to establish a robust protocol under real-life conditions.

CONCLUSIONS

This fast and reliable dalbavancin quantitation method could improve current pediatric clinical practice by enabling data collection for future dose recommendations in special patient populations.

Trough levels of dalbavancin during long-term treatment of prosthetic joint infections

INTRODUCTION

Dalbavancin is a lipoglycopeptide with an exceptionally long half-life that allows simplified administration, which may be of value in long-term treatment of bone and joint infections, such as prosthetic joint infections (PJIs). The objective was to determine trough (Cmin) values of dalbavancin during long-term PJI treatment according to the recommendation of the Swedish National Guidelines for Bone and Joint Infections: a loading dose of 1,500 mg on day 1 and another 1,500 mg on days 8-14, followed by day 28 administration of 1,000 mg every two weeks or 500 mg per week.

PATIENTS/METHODS

Twelve patients with PJI treated with at least six doses of dalbavancin were prospectively followed up, serum samples were collected, and renal function was investigated. Dalbavancin concentrations were measured using ultra-high pressure liquid chromatography coupled with unispray tandem mass spectrometry (UHPLC-MS/MS).

RESULTS

The median serum concentration (Cmin) 14 days after the first 1,500 mg dose was 36.3 mg/L (range: 6.6-62.4 mg/L). The median trough value at the date of the last given dose (1,000 mg) after a total of 6-7 doses was 53.6 mg/L (range: 32.0-97.5 mg/L). Three patients showed a tendency towards successive accumulation of dalbavancin during treatment. None of the patients showed any significant impairment in renal function.

CONCLUSIONS

Therapeutic drug monitoring during long-term dalbavancin treatment is recommended to avoid the risk of accumulation and unnecessarily high trough levels. In many cases, such monitoring can allow the dosing interval to be extended.

Exploratory analysis of long-term suppressive therapy with dalbavancin in ventricular assist device infections caused by Staphylococcus aureus

To analyze dalbavancin's potential for long-term suppressive therapy in patients with infected ventricular assist devices (VAD), the VAD register of Heidelberg University Hospital was searched for patients who received dalbavancin for long-term suppression therapy. Clinical data, laboratory, and microbiological results were extracted. Healthcare utilization was analyzed by number of hospitalizations before and during dalbavancin therapy with a generalized linear mixed model. Drug safety was investigated with regard to liver and renal function, and thrombocyte count. Thirteen patients were included in the study; receiving a regimen of 1500 mg dalbavancin at day 1 and day 8 with repetition of the cycle at day 42. The mean follow-up time was 254 days (IQR 252). Eight patients were treated for driveline infection and five patients for driveline and blood stream infection, all of them caused by Staphylococcus aureus. The majority of patients (n = 11/13) underwent surgical wound debridement and intravenous antibiotic therapy before start of dalbavancin. Under dalbavancin therapy, no blood stream infection was observed and significantly fewer hospitalizations occurred with an odds ratio of 0.27 (p < 0.001). In four patients, elevations of liver transaminases were detected and led to discontinuation of dalbavancin therapy in one patient.

Gram-positive infections in special populations. Expert view on the role of dalbavancin

INTRODUCTION

This review considers special populations as those patients for whom Gram-positive infections are particularly challenging to treat. We examine the potential benefits of dalbavancin in these patients.

AREAS COVERED

We focus on patients with renal impairment, hepatic failure or obesity, and, also, pediatric patients, elderly patients and socially vulnerable individuals. Five independent experts conducted exhaustive literature searches on PubMed. Papers were selected for inclusion according to their relevance to the topic. For each special population, we outline the most significant characteristics for infection management, describing the challenges of the most frequent Gram-positive infections, and reviewing the potential role of dalbavancin.

EXPERT OPINION

Dalbavancin may be a valid alternative to overcome the difficulties of infection management in these populations. We hope our insights will prove useful for patient-centered care. A long half-life, evidence-based efficacy and good safety profile make dalbavancin an adequate option, particularly for patients for whom oral treatment or continued IV access may be challenging, or those for whom hospital stay is more impactful. [Figure: see text].

Effect of body mass index on the timing of therapeutic drug monitoring-guided dalbavancin dosing in patients with osteoarticular infections

BACKGROUND

Recently, we documented that proactive therapeutic drug monitoring (TDM) allowed the successful individualization of the timing of dalbavancin administration in patients requiring prolonged antibiotic treatment. Here, we aimed to identify variables associated with the timing of TDM-guided dalbavancin dosing in patients who underwent proactive dalbavancin TDM.

METHODS

Adult patients who received at least three 1500 mg doses of dalbavancin for osteoarticular infections were included in the study. Univariate and multivariate linear regression analyses were performed, considering the timing of dalbavancin administrations as the dependent variable and clinical features as dependent covariates.

RESULTS

Sixty-three patients [65% male, mean (SD) age 64 ± 16 years] fulfilling the inclusion criteria were included in the study. Patients were given a mean (SD) 6.4 ± 5.0 injections of dalbavancin over a mean (SD) period of 198 ± 213 days. Dalbavancin was administered every 40 ± 7 days (range:16-71 days). By univariate linear regression analyses, patient age (P = 0.002), BMI (P < 0.001), serum albumin (P = 0.011) and the duration of dalbavancin treatment (P = 0.012) was found to be associated with the timing of dalbavancin administration. The BMI was the only variable retained in the final multivariate model (P < 0.001). A highly significant reduction in timing of dalbavancin administration was observed between patients with obesity, overweight and normal weight [mean (SD) 30 ± 7 versus 38 ± 4 versus 43 ± 7 days].

CONCLUSIONS

Overweight and obesity significantly impacted on dalbavancin pharmacokinetics in patients with osteoarticular infections requiring prolonged antibiotic treatment. These effects can be handled by proactive TDM.

Management of methicillin-resistant Staphylococcus aureus bloodstream infections: a comprehensive narrative review of available evidence focusing on current controversies and the challenges ahead

INTRODUCTION

Bloodstream infections (BSIs) caused by Staphylococcus aureus are common worldwide, representing one of the most relevant issues in clinical infectious diseases practice. In particular, BSIs by methicillin-resistant S. aureus (MRSA-BSI) are still today a challenge since mortality burden remains elevated although decades of research.

AREAS COVERED

The following topics regarding MRSA-BSI were reviewed and discussed by resorting to best available evidence retrieved from PubMed/MEDLINE up to October 2024: i) epidemiology; ii) microbiology; iii) classification, with a focus on complicated and not complicated forms; iv) the structured approach to the patient; v) pharmacokinetics and pharmacodynamics of the main antimicrobial options; vi) controversies regarding the best therapeutic approach.

EXPERT OPINION

Despite ongoing efforts to better stratify and manage MRSA-BSI, there is no universally accepted classification system accurately distinguishing between uncomplicated/low risk and complicated/high risk forms. Biomarkers such as interleukin(IL)-10 hold promise in order to enable a more precise stratification, premise for an appropriate treatment plan. There is a theoretical rationale for implementing a combination therapy including a beta-lactam agent upfront, especially for patients considered at higher risk of unfavorable outcomes, but further data are necessary, and the same applies to newer adjuvants. Novel microbiological techniques may help in guiding antimicrobial duration.

Usefulness of a hub and spoke TDM-guided expert clinical pharmacological advice program of dalbavancin for optimizing very long-term curative or suppressive treatment of chronic staphylococcal infections

A hub and spoke model for optimizing long-term treatment of chronic staphylococcal infections with dalbavancin based on therapeutic drug monitoring (TDM)-guided expert clinical pharmacological advice (ECPA) was implemented. This multicentric retrospective cohort study included patients receiving dalbavancin monotherapy lasting >6 weeks at different spoke hospitals having treatment optimized by means of a TDM-guided ECPA program at a hub hospital. Optimal pharmacokinetic/pharmacodynamic target against staphylococci with an MIC up to 0.125 mg/L was defined as dalbavancin concentrations >8.04 mg/L. Patients received dalbavancin therapy for curative (curative group) or suppressive (suppressive group) purposes. Clinical outcome was assessed by means of repeated ambulatory visits. A total of 12 spoke hospitals applied for 414 TDM-based ECPA for 101 patients, of whom 64.4% (65/101) were treated for curative and 35.6% (36/101) were for suppressive purposes. In the curative and suppressive groups, TDM-based ECPA optimized treatment for up to 14 and 28 months, respectively, and ensured median optimal exposure of 95.7% and 100%, respectively. In the curative group, having <70% of treatment time with concentrations above the optimal target increased failure risk [odds ratio (OR), 6.71; confidence interval (CI), 0.97-43.3; P = 0.05]. In the suppressive group, infective endocarditis was associated with an increased risk of ineffective treatment (OR, 8.65; CI, 1.29-57.62; P = 0.046). Mild adverse events were reported in 4.5% (5/101) of cases. A hub and spoke TDM-guided ECPA program of dalbavancin may be cost-effective for optimizing long-term treatment of chronic staphylococcal infections and for patients admitted to hospitals lacking in-house MD clinical pharmacologists.

Central-venous-catheter-related bloodstream infections in adult patients with sickle cell disease: a retrospective, two-centre study

PURPOSE

Although catheter-related infections are the leading cause of bloodstream infections in patients with sickle cell disease (SCD), data are scarce in adult patients. The objectives of the present study were to describe central-venous-catheter-related bloodstream infections in patients with SCD and identify risk factors.

METHODS

We conducted a retrospective, observational study of adult patients with SCD diagnosed with central-venous-catheter-related bloodstream infections between 2011 and 2023 in two SCD reference centres. Each patient with SCD and a bloodstream infection related to a totally implantable venous access port was matched with two control patients with SCD and an infection-free totally implantable venous access port.

RESULTS

Thirty-five (6.6%) of the 534 patients experienced a total of 69 central-venous-catheter-related bloodstream infections. Concomitant vaso-occlusive crises were observed for 81.2% of the infections. The 30-day mortality rate was 2.8%, and the infection recurrence rate was 45.7%. We observed 26 totally implantable venous access port-related bloodstream infections in 19 patients, with an incidence rate of 0.31 per 1000 catheter-days. After adjustment, the frequency of hospital admission for a vaso-occlusive crisis (odds ratio (OR) [95% confidence interval (CI)] = 1.6 [1.2-2.4]) and the presence of a psychiatric comorbidity (19.8 [4.0-148.1]) remained significantly associated with totally implantable venous access port-related bloodstream infections. Suboptimal antibiotic levels were observed in five (39%) of the 13 patients having undergone therapeutic drug monitoring. The treatment failed in four (80%) of the five patients, who presented with glomerular hyperfiltration.

CONCLUSION

A central-venous-catheter-related bloodstream infection is a severe complication in adult patients with SCD and is associated with psychiatric comorbidities and severe SCD.

Dalbavancin to facilitate early discharge in the treatment of complex musculoskeletal infections: a multi-centre real-life application

Dalbavancin is a lipoglycopeptide with a half-life of 14 d, significantly reducing the need for daily antibiotic dosing. Although dalbavancin is approved for acute bacterial skin and skin structure infections, its off-label use in complex musculoskeletal infection (MSKI) is increasing. Evidence on its effectiveness for MSKI, especially in facilitating early discharge for patients unsuitable for oral or OPAT (outpatient parenteral antimicrobial therapy) treatments, is limited. This multi-centre observational study aims to evaluate dalbavancin's role in facilitating discharge and improving clinical outcomes in MSKI. Method: this study included adult patients treated with dalbavancin between January 2017 and December 2022 across five hospitals in the UK and France. Data on patient demographics, clinical characteristics, microbiology and treatment outcomes were collected using a standardised form. The study also compared treatment costs between dalbavancin and hypothetical alternatives involving either inpatient care or OPAT. Clinical success was defined as the absence of definite failure based on the OVIVA (oral versus intravenous antibiotics) trial criteria. Results: a total of 39 patients were included, with a median age of 51 years (interquartile range (IQR) 40-72). Prosthetic joint infections (38 %) and septic arthritis (31 %) were the most common indications for dalbavancin use. The primary pathogens identified were Staphylococcus aureus (51 %) and coagulase-negative staphylococci (44 %). Dalbavancin was primarily chosen due to poor adherence or lack of OPAT options in 77 % of cases and for convenience in 23 %. In the necessity group, the use of dalbavancin resulted in a median cost saving of GBP 8894 per patient, and 31 inpatient days were avoided. Of the 32 patients (82 %) assigned a definite outcome, 72 % achieved clinical success. No significant adverse drug reactions were reported. Conclusion: this study fills an important evidence gap by demonstrating that dalbavancin is a viable and cost-effective option for MSKI patients that are unsuitable for oral or OPAT treatments. Dalbavancin facilitates early discharge, reduces hospital stays and achieves comparable clinical outcomes to conventional therapies.

Real-world evidence of dalbavancin effectiveness as consolidation therapy in infective endocarditis due to Enterococcus spp

Enterococcal endocarditis (EIE) affects elderly patients, with high rates of complications and mortality, and dalbavancin (DBV) exhibits significant antimicrobial activity against most enterococci. However, data are lacking on the use of DBV in EIE. The main objective was to evaluate the outcomes of treatment with DBV in the consolidation therapy of IE by Enterococcus spp.

METHODS

Spanish-French retrospective observational study of patients with EIE enrolled between November 2016 and June 30, 2022 receiving DBV in consolidation phase and followed for ≥12 months.

RESULTS

Ninety-eight patients were enrolled, 69.4 % male, with mean age of 71.2 (±12.51) years and median Charlson index of 5 (IQR 3-7). Criteria for definite IE were met by 84.7%; 60.2 % had IE on native valve, 26.5 % late prosthetic IE, 8.2 % early prosthetic IE, 2 % cardiovascular implantable electronic-IE (CIE-IE), and 3.1 % CIE-IE and valve. Aortic valve involvement was observed in 66.3 %. E. faecalis was isolated in 86.7 %, E. faecium in 11.2 %; 32.6 % underwent surgery, and these had a higher cure rate (100 % vs 75.8 %; p = 0.005) and lower mortality (0 vs 13.6 %; p = 0.029). DBV was administered to facilitate discharge in 88.8 %. Total dose was 2500 mg (1500-3000) over 3.5 weeks (2-4). Loss to follow-up was 0 %, relapse rate 8.2 %, 1-year IE-related mortality 3.1 %, and clinical cure rate 81.2 %. Severe adverse events affected 1 % (acute tubular necrosis). Hospital stay was reduced by 21 days (14-28).

CONCLUSIONS

DBV appears to be highly effective, safe, and cost-effective as consolidation therapy in patients with IE caused by Enterococcus spp., with minimal adverse events.

Multidose Dalbavancin Population Pharmacokinetic Analysis for Prolonged Target Attainment in Patients Requiring Long-Term Treatment

Introduction: Dalbavancin (DAL) is a long-acting lipoglycopeptide active against Gram-positive bacteria, including multidrug-resistant isolates. A growing body of evidence supports its efficacy in various difficult-to-treat infections. DAL shows time-dependent bactericidal activity in vitro at free drug concentrations equal to 4×MIC values. However, the optimal dosing scheme for achieving the PK/PD target in multidose treatment has not been fully established. Methods: Pharmacokinetic analysis was based on a nonlinear mixed effects modelling approach performed in NONMEM v7.5/Pirana, while R was used for data management and graphical summaries. Final model parameters were used to simulate the plasma disposition of DAL by Monte Carlo simulations to determine the multidose DAL regimen associated with a 90% target attainment of 100% fT > 4×MIC. Results: A two-compartmental model with first-order elimination and allometric-scaled bodyweight best described DAL disposition in patients with CLcr > 30 mL/min. Monte Carlo simulations showed that two 1500 mg DAL doses 7 days apart granted an optimal PTA > 90% of 100% fT > 4×MIC up to 5, 4, and 3 weeks in patients weighting from 40-80 kg, 80-120 kg and 120-200 kg, respectively. An additional third 1500 mg dose at the above time points by weight bands may extend the optimal PTA up to 9, 7, and 6 weeks of total treatment. Conclusions: Two 1500 mg DAL doses administered 7 days apart could be a valuable starting strategy for patients of all weight classes with CLcr > 30 mL/min. In patients requiring long-term DAL treatment, the optimal timing of additional administrations should be guided by routine TDM or empirically through patients' total body weight when TDM is unavailable.

Long-Acting Antibiotics: New Opportunities Beyond Acute Bacterial Skin and Skin Structure Infections (ABSSSIs)!

Currently, two long-acting antibiotics are available: oritavancin (ORI) and dalbavancin (DBV) [...].

A systematic review of dalbavancin efficacy as a sequential therapy for infective endocarditis

INTRODUCTION

Dalbavancin is an antibiotic characterized by an extended half-life and efficacy against methicillin-resistant Staphylococci. Currently, there are only narrative reviews summarizing the evidence about the use of dalbavancin for infective endocarditis (IE), many of which are focused primarily on its use as consolidation therapy. For this reason, we conducted a systematic review to describe the clinical efficacy and the safety of dalbavancin in IE treatment.

METHODS

We searched for available evidence using the MEDLINE (PubMed), Embase, Scopus, Cochrane Library and Web of Science libraries, with no restrictions regarding the publication year. The risk of bias was performed using the Cochrane ROBINS-I tool for the comparative studies and the Newcastle-Ottawa Scale for descriptive studies.

RESULTS

Nine studies were included. All of them were observational. Native valve endocarditis was the most common kind of IE found in the studies' populations (128/263, 48.7%), followed by prosthetic valve endocarditis, and cardiovascular implantable electronic device-related endocarditis. Coagulase-negative Staphylococci were the most common pathogens isolated (83/269, 30.1%), followed by S. aureus, Enterococci spp and Streptococci spp. Five out of nine studies documented a clinical failure rate of less than 10%. Dalbavancin showed a favourable safety profile. Dalbavancin appears to be a promising option for the consolidation therapy of IE. However, further studies comparing dalbavancin with standard of care are needed.

PROSPERO REGISTRATION NUMBER

CRD42023430032.

Therapeutic drug monitoring of antibiotics for methicillin-resistant Staphylococcus aureus infections: an updated narrative review for clinicians

BACKGROUND

Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are associated with high mortality rates. Optimal antibiotic dosage plays a crucial role in reducing MRSA burden; thus, the use of therapeutic drug monitoring (TDM) in the clinical practice, especially of new drugs such as ceftobiprole, ceftaroline, dalbavancin, and oritavancin, should be implemented.

OBJECTIVES

We aim to examine and summarize the available evidence about TDM of anti-MRSA molecules, with a focus on pneumonia, endocarditis and vascular infections, and bone and joint infections.

SOURCES

We applied 'therapeutic drug monitoring' and 'Staphylococcus aureus' as search terms in PubMed, considering a time frame of 24 years (2001-2024). Articles in English language, non-duplicated, evaluating antibiotic therapeutic target, and role of TDM were included in the study.

CONTENT

In this review, available data for therapeutic target and TDM were critically analysed and summarized and suggestions about the use of old and new anti-MRSA antibiotics were provided, focusing on optimal dosages, tissue penetration according to infection types, and toxicity. Limitations to the widespread use of TDM in clinical practice were discussed.

IMPLICATIONS

The use of TDM may play an important role for the optimal management of patients with MRSA infections and may impact on patient outcomes by increasing efficacy and reducing the risk of adverse events. TDM may be implemented in clinical practice; however, several limitations such as the wide variability in the methodology and the need for skilled personnel need to be considered.

Bridging the Gap: A Systematic Review with Expert Opinion on the Use of Dalbavancin for In-Label and Off-Label Indications in Pediatric Patients

OBJECTIVES

The aim of this work was to perform a systematic review assessing the pharmacokinetic/pharmacodynamic (PK/PD) properties of dalbavancin and the clinical use for in-label and off-label indications in pediatric patients.

METHODS

Two authors independently searched the PubMed-MEDLINE and Scopus databases and clinicaltrials.gov up to 20 November 2024, to retrieve randomized controlled trials (RCTs), observational studies, PK studies, and case series/reports assessing dalbavancin PK/PD properties or the clinical use for both in-label and off-label indications in pediatric patients. Data were independently extracted by the two authors, and the quality of the included studies was independently assessed by means of specific tools according to study design. Clinical success was selected as the primary outcome. Descriptive statistics were used for summarizing the retrieved data. Subgroup analysis according to PK/PD data, as well as in-label and off-label indications, was performed.

RESULTS

After screening 206 articles, nine studies were included in the systematic review (one RCT, three PK studies, and five case series/reports; n = 267). Dalbavancin exposure was 30% lower in pediatric patients compared to adults. In acute bacterial skin and skin structure infections (ABSSSIs), the overall clinical success of dalbavancin was 96.1-97.3% and 92.9% in RCT and case series, respectively. Bone and joint infections (60.7%) and central-line-associated bloodstream infections (14.3%) represented the most common dalbavancin off-label indications in pediatric patients. Overall, the clinical success for off-label indications was 92.9%. The rate of adverse events ranged from 7.1% to 10.7%.

CONCLUSIONS

Our systematic review summarized evidence concerning the PK/PD properties of dalbavancin and its use for in-label or off-label indications in pediatric patients. The available findings suggest that dalbavancin may be a valuable alternative for the management of ABSSSIs and/or off-label indications in pediatric patients according to efficacy and safety data, allowing for a potential minimized duration of hospital stay.

Model-Based Dose Identification of Dalbavancin for Long-Term Suppressive Outpatient Treatment of Ventricular Assist Device Infections

Increasing evidence suggests that dalbavancin is an effective long-term treatment for ventricular assist device (VAD) infections, with various prolonged dosing regimens currently in use. This retrospective study aimed to assess dalbavancin pharmacokinetics in VAD patients and identify optimal, feasible dosing regimens for long-term suppressive outpatient therapy. Data from Heidelberg University Hospital's VAD register were analyzed using non-linear mixed-effects modeling for pharmacokinetic analysis and dosing simulations (Lixoft®). The probability of target attainment (PTA) and cumulative fraction of response (CFR) were calculated for different protein-binding scenarios considering the minimum inhibitory concentration (MIC) distribution of Staphylococcus aureus. Using data from 13 patients with 38 blood samples, a two-compartment model best described the dalbavancin pharmacokinetics, with a typical value for clearance of 0.050 L/h, central volume of distribution of 6.5 L, and peripheral volume of 15.4 L. No covariates significantly improved the model fit. The observed protein binding varied between 96 and 98%. Dosing simulations demonstrated that 1500 mg every 3 weeks ensured the target attainment for stasis at MIC values of 0.125 mg/L (PTA ≥ 90%) up to a protein binding of 99%. Considering the CRF, longer dosing intervals up to 5 weeks might be possible. Depending on individual MICs and protein binding, a dalbavancin regimen of 1500 mg every 3 to 5 weeks therefore appears to be a valuable option for outpatient therapy of VAD infections. Therapeutic drug monitoring should be considered to manage inter-individual variability and to support clinicians in long-term treatments of subacute and chronic infections.

Population Pharmacokinetics and Pharmacodynamics of Dalbavancin and C-Reactive Protein in Patients with Staphylococcal Osteoarticular Infections

BACKGROUND AND OBJECTIVE

Dalbavancin is increasingly used for the long-term treatment of chronic osteoarticular infections. A population pharmacokinetic/pharmacodynamic (PK/PD) analysis for assessing the relationship between dalbavancin exposure and C-reactive protein (C-RP) over time was conducted.

METHODS

Non-linear mixed-effect modeling was fitted to dalbavancin and C-RP concentrations. Monte Carlo simulations assessed the weekly percentage of C-RP reduction associated with different dosing regimens, starting from baseline to < 1 mg/dL.

RESULTS

A total of 45 patients were retrospectively included in the analysis. The PK of dalbavancin was described by a two-compartment model, and the PD of C-RP was described by an indirect turnover maximum inhibition model. The total dalbavancin concentration model estimate producing 50% of maximum C-RP production inhibition (IC50) was 0.70 mg/L. Monte Carlo simulations showed that in patients with staphylococcal osteoarticular infections targeting total dalbavancin concentrations at > 14.5 mg/L at any time point may achieve C-RP production inhibition over time in > 95% of patients. Based on this, the findings showed that a cumulative dose of 3000 mg administered in the first 3 weeks may lead to a > 90% C-RP decrease versus baseline in approximately 5-6 weeks. In patients needing treatment prolongation, an additional 1500 mg dose after this period may maintain C-RP concentrations < 1 mg/dL for other 3 weeks.

CONCLUSIONS

A decrease in C-RP is related to dalbavancin exposure in osteoarticular infections. Targeting dalbavancin plasma concentrations above the efficacy threshold may be associated with effective treatment.

Real-life experience with IV dalbavancin in Canada; results from the CLEAR (Canadian LEadership on Antimicrobial Real-life usage) registry

OBJECTIVES

We report the use of IV dalbavancin in Canadian patients using data captured by the national CLEAR registry.

METHODS

The CLEAR registry uses the web-based data management program, REDCap™ (online survey https://rcsurvey.radyfhs.umanitoba.ca/surveys/?s=TPMWJX98HL) to facilitate clinicians entering details associated with their clinical experiences using IV dalbavancin.

RESULTS

Data were available for 40 patients. The most common infections treated were acute bacterial skin and skin structure infection (ABSSSI) (62.5% of patients), bone/joint infection (22.5%), bloodstream/vascular infection (7.5%) and endocarditis (5.0%). Dalbavancin was used as directed (75.0%) and empiric therapy (25.0%). MRSA was the most common identified pathogen (70.0%). Dalbavancin was used both in outpatient (e.g., emergency department) (65.0%), and inpatient treatment settings (e.g., hospital ward) (35.0%). Dalbavancin was used due to the convenience of a single dose treatment (77.5%) as well as to facilitate hospital discharge (7.5%). Dalbavancin was primarily used alone (90.0%), and most commonly using a single 1500 mg dose (77.5%). Microbiological success (pathogen eradicated or presumed eradicated) occurred in 88.2% of known cases, while clinical success (cure and/or improvement) occurred in 93.3% of known cases. No adverse events were reported.

CONCLUSIONS

In Canada, IV dalbavancin is used as both directed and empiric therapy to treat ABSSSI as well as off-label (bone/joint, bacteremia/vascular, endocarditis, device-related) infections. It is used in both outpatient and inpatient settings due primarily to its convenience as a single-dose treatment regimen and to facilitate early hospital discharge. Dalbavancin use is associated with high microbiological and clinical cure rates along with an excellent safety profile.

Antimicrobial peptides: Opportunities and challenges in overcoming resistance

Antibiotic resistance represents a global health threat, challenging the efficacy of traditional antimicrobial agents and necessitating innovative approaches to combat infectious diseases. Among these alternatives, antimicrobial peptides have emerged as promising candidates against resistant pathogens. Unlike traditional antibiotics with only one target, these peptides can use different mechanisms to destroy bacteria, with low toxicity to mammalian cells compared to many conventional antibiotics. Antimicrobial peptides (AMPs) have encouraging antibacterial properties and are currently employed in the clinical treatment of pathogen infection, cancer, wound healing, cosmetics, or biotechnology. This review summarizes the mechanisms of antimicrobial peptides against bacteria, discusses the mechanisms of drug resistance, the limitations and challenges of AMPs in peptide drug applications for combating drug-resistant bacterial infections, and strategies to enhance their capabilities.

Proactive therapeutic monitoring of dalbavancin concentrations in the long-term management of chronic osteoarticular/periprosthetic joint infections

Here, we describe the use of proactive therapeutic drug monitoring (TDM) to individualize the optimal timing of drug injections in 16 adult patients with chronic osteoarticular infections receiving a median of 7 injections of dalbavancin (up to 12 injections in 15 months). Dalbavancin injections were repeated at medians of 39-47 days, with infusion intervals ranging from 26 to 69 days. TDM can facilitates a precise, targeted use of dalbavancin for infections requiring prolonged treatments.

The MIC distribution of dalbavancin differs between different coagulase-negative staphylococci

Background

CoNS constitute a significant part of the human microbiota of skin and mucous membranes. They can cause nosocomial infections, and have shown decreased susceptibility to several antibiotics. The few remaining treatment options include (lipo)glycopeptides such as dalbavancin. However, there is a lack of knowledge concerning whether susceptibility to lipoglycopeptides varies between different species of CoNS.

Objectives

To determine the susceptibility to dalbavancin in different species of CoNS.

Methods

We investigated 480 bacterial isolates from 10 CoNS species: Staphylococcus epidermidis, Staphylococcus capitis, Staphylococcus caprae, Staphylococcus haemolyticus, Staphylococcus lugdunensis, Staphylococcus warneri, Staphylococcus pettenkoferi, Staphylococcus hominis, Staphylococcus sciuri and Staphylococcus simulans. The isolates were randomly selected from different sources of infection, including blood isolates, as well as deep and superficial infections. Antibiotic susceptibility was tested with the gradient test method.

Results

There was a statistically significant difference (ANOVA; P < 0.0001) in the MIC distribution for dalbavancin between different CoNS species. S. sciuri was the least susceptible species, with 90% of the isolates having an MIC value for dalbavancin above the EUCAST breakpoint of 0.125 mg/L. The lowest MIC90 values were seen for S. capitis, S. simulans and S. caprae (all 0.032 mg/L).

Conclusions

This study demonstrated a difference in dalbavancin susceptibility between different CoNS species, suggesting that species-specific breakpoints for CoNS should be further investigated.

Optimizing Antibiotic Therapy for Intravenous Drug Users: A Narrative Review Unraveling Pharmacokinetics/Pharmacodynamics Challenges

Intravenous drug users (IVDUs) face heightened susceptibility to life-threatening gram-positive bacterial infections, particularly methicillin-resistant Staphylococcus aureus (MRSA). While the standard antibiotic dosing strategies for special patients, such as obese or critically ill individuals, are known to be inadequate, raising concerns about treatment efficacy, a similar sort of understanding has not been assessed for IVDUs yet. With this in mind, this review examines the pharmacokinetic/pharmacodynamic characteristics of antibiotics commonly used against gram-positive bacteria in IVDUs. Focusing on daptomycin, vancomycin, teicoplanin, aminoglycosides, and the novel lipoglycopeptide dalbavancin, the study reveals significant pharmacokinetic variations in IVDUs, suggesting the need for personalized dosing. Concomitant opioid substitution therapy and other factors, such as malnutrition, contribute to altered pharmacokinetics/pharmacodynamics, emphasizing the importance of targeted therapeutic drug monitoring. Overall, our study calls for increased awareness among clinicians regarding the unique pharmacokinetic/pharmacodynamic challenges in IVDUs and advocates for tailored antibiotic dosing strategies to enhance treatment outcomes in this marginalized population.

Implementation and validation of a Bayesian method for accurately forecasting duration of optimal pharmacodynamic target attainment with dalbavancin during long-term use for subacute and chronic staphylococcal infections

Dalbavancin is increasingly being used for long-term treatment of subacute and chronic staphylococcal infections. In this study, a new Bayesian model was implemented and validated using MwPharm software for accurately forecasting the duration of pharmacodynamic target attainment above the efficacy thresholds of 4.02 mg/L or 8.04 mg/L against staphylococci. Forecasting accuracy improved substantially with the a posteriori approach compared with the a priori approach, particularly when two measured concentrations were used. This strategy may help clinicians to estimate the duration of optimal exposure with dalbavancin in the context of long-term treatment.

Therapeutic drug monitoring of glycopeptide antimicrobials: An overview of liquid chromatography-tandem mass spectrometry methods

Therapeutic drug monitoring (TDM) is a critical clinical tool used to optimize the safety and effectiveness of drugs by measuring their concentration in biological fluids. These fluids are primarily plasma or blood. TDM, together with real-time dosage adjustment, contributes highly to the successful management of glycopeptide antimicrobial therapies. Understanding pharmacokinetic/pharmacodynamic (PK/PD) properties is vital for optimizing antimicrobial therapies, as the efficacy of these therapies depends on both the exposure of the patient to the drug (PK) and pharmacodynamic (PD) parameters such as the in vitro estimated minimum drug concentration that inhibits bacterial growth (MIC). Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) is widely recognized as the gold standard for measuring small molecules, such as antibiotics. This review provides a comprehensive overview of LC-MS/MS methods available for TDM of glycopeptide antibiotics, including vancomycin, teicoplanin, dalbavancin, oritavancin, and telavancin.

Therapeutic Drug Monitoring of Dalbavancin in Real Life: A Two-Year Experience

Dalbavancin is a long-acting lipoglycopeptide that is registered for the treatment of acute bacterial skin and skin structure infections, and it is also increasingly used for infections that require prolonged antibiotic treatment. Here, we present the results from the first 2 years of a service set up in December 2021 for the therapeutic drug monitoring (TDM) of dalbavancin in clinical settings. In particular, we compared the trough concentration (Cmin) to maximum concentration (Cmax) in patients with osteoarticular infections receiving prolonged treatment with dalbavancin. Log-linear regression models were used to estimate the timing of dalbavancin administration with the goal of maintaining Cmin concentrations of >8 mg/L in the two TDM-based strategies. From December 2021 to November 2023, 366 TDMs of dalbavancin from 81 patients were performed. The Cmin and Cmax concentrations of dalbavancin ranged from 4.1 to 70.5 mg/L and from 74.9 to 995.6 mg/L, respectively. With log-linear regression models, we estimated that each injection should be administered every 42-48 days to maintain the Cmin concentrations. Out of the 81 patients, 37 received at least three doses of dalbavancin for the treatment of osteoarticular infections. Despite there being no significant differences in the days of dalbavancin treatment (130 ± 97 versus 106 ± 102 days), the patients in the Cmax-based TDM group received a significantly lower number of dalbavancin injections (5.2 ± 1.8 versus 7.3 ± 2.6 injections, p = 0.005), and they were administered over a longer period of time (40 ± 10 versus 29 ± 14 days, p = 0.013) than in the Cmin-based TDM group. In conclusion, Cmax-based TDM was associated with a significant reduction in the inter-individual variability of dalbavancin concentrations and lower drug dosing frequency than those of Cmin-based TDM. This approach could, therefore, favor a more rational and targeted use of dalbavancin in patients requiring prolonged treatment.

Long-Term Suppressive Therapeutic-Drug-Monitoring-Guided Dalbavancin Therapy for Cardiovascular Prosthetic Infections

Dalbavancin represents a promising treatment for cardiovascular prosthetic infections due to its prolonged half-life, bactericidal activity, large spectrum of activity, and excellent biofilm penetration. However, the use of dalbavancin in this setting is limited, and only a few cases have performed therapeutic drug monitoring (TDM) analysis to optimize dosage in suppressive treatments longer than 4 weeks. Our retrospective case series reports the use of dalbavancin in a small cohort of patients with cardiovascular prosthetic infections (cardiac implantable electronic device infections (CEDIs), prosthetic valve endocarditis (PVE), prosthetic vascular graft infections (PVGIs)) treated with dalbavancin as sequential therapy. From May 2019 to May 2023, 14 patients were included: eight cases of PVE (57.1%), seven cases of PVGI (50%), three cases of CEDI (21.4%), and four cases with overlap of infection sites (28.6%). The main pathogen was Staphylococcus aureus (35.7%). Prosthesis replacement was obtained in four patients (28.6%). The median time between symptom onset and the end of treatment was 15 weeks (IQR 7-53), with a median duration of dalbavancin therapy of 8 weeks (IQR 1 to 45 weeks) and 3.5 doses per patient. Among patients managed with TDM-guided strategy, dalbavancin infusion intervals ranged from 4 to 9 weeks. The median length of follow-up was 65 weeks (IQR 23 to 144 weeks). Clinical success was achieved in 10 cases (76.9%); all clinical failures occurred in patients with the implant retained. Among patients monitored by TDM, clinical success was 87.5% vs. 60% in patients treated without TDM. Because of pharmacokinetic individual variability, dalbavancin TDM-guided administration could improve clinical outcomes by individualizing dosing and selecting dosing intervals. This case series seems to suggest a promising role of long-term suppressive dalbavancin treatment for difficult-to-treat cardiovascular prosthesis infection, also with limited surgical indications.