Once-Weekly Dalbavancin versus Standard-of-Care Antimicrobial Regimens for Treatment of Skin and Soft-Tissue Infections

Simulated Target Attainment of Multidose Regimens of Dalbavancin for Prolonged Durations of Therapy

Background

Dalbavancin is a long-acting lipoglycopeptide antibiotic that is increasingly utilized for infections that require prolonged treatment durations despite the lack of Food and Drug Administration approval for these indications. There is no consensus regarding optimal dosing of dalbavancin for these infections and no available pharmacokinetic studies to identify optimal dosing for long-term use.

Methods

An in silico pharmacokinetic simulation was performed to assess the predicted dalbavancin concentration resulting from commonly utilized dosing regimens, in addition to modified regimens. The primary endpoint evaluated was days of median 24-hour free area under the curve over the minimum inhibitory concentration (AUC/MIC) >27.1, the established PK target.

Results

A dosing regimen of 1500 mg on day 0 and day 7 resulted in median AUC/breakpoint value above the target for 57 days (lower 95% confidence interval [CI], 37 days). A modified regimen of 1500 mg on day 0 and day 21 resulted in an additional 11 days of median AUC/breakpoint target attainment. The other standard dosing regimen modeled was 1000 mg on day 0, then 500 mg weekly for 5 doses. This regimen achieved the AUC/breakpoint target for 76 days (lower 95% CI, 59 days). This regimen was modified to 1000 mg on day 0, then 500 mg on days 14 and 28, which shortened the median effective treatment duration by 14 days but required 3 fewer doses.

Conclusions

These simulated results, when combined with the favorable observational data, support the use of commonly reported dalbavancin regimens for prolonged therapy durations. In addition, these pharmacokinetic/pharmacodynamic data support extending the dosing interval beyond the frequently reported weekly regimens, which should be investigated further with a clinical trial.

Cost evaluation of continuation of therapy with dalbavancin compared to standard-of-care antibiotics alone in hospitalized persons who inject drugs with severe gram-positive infections

PURPOSE

Persons who inject drugs (PWID) are at risk for severe gram-positive infections and may require prolonged hospitalization and intravenous (IV) antibiotic therapy. Dalbavancin (DBV) is a long-acting lipoglycopeptide that may reduce costs and provide effective treatment in this population.

METHODS

This was a retrospective review of PWID with severe gram-positive infections. Patients admitted from January 1, 2017, to November 1, 2019 (standard-of-care [SOC] group) and from November 15, 2019, to March 31, 2022 (DBV group) were included. The primary outcome was the total cost to the healthcare system. Secondary outcomes included hospital days saved and treatment failure.

RESULTS

A total of 87 patients were included (37 in the DBV group and 50 in the SOC group). Patients were a median of 34 years old and were predominantly Caucasian (82%). Staphylococcus aureus (82%) was the most common organism, and bacteremia (71%) was the most common type of infection. Compared to the SOC group, the DBV group would have had a median of 14 additional days of hospitalization if they had stayed to complete their therapy (P = 0.014). The median total cost to the healthcare system was significantly lower in the DBV group than in the SOC group ($31,698.00 vs $45,093.50; P = 0.035). The rate of treatment failure was similar between the groups (32.4% in the DBV group vs 36% in the SOC group; P = 0.729).

CONCLUSION

DBV is a cost-saving alternative to SOC IV antibiotics for severe gram-positive infections in PWID, with similar treatment outcomes. Larger prospective studies, including other patient populations, may demonstrate additional benefit.

Priorities and Progress in Gram-positive Bacterial Infection Research by the Antibacterial Resistance Leadership Group: A Narrative Review

The Antibacterial Resistance Leadership Group (ARLG) has prioritized infections caused by gram-positive bacteria as one of its core areas of emphasis. The ARLG Gram-positive Committee has focused on studies responding to 3 main identified research priorities: (1) investigation of strategies or therapies for infections predominantly caused by gram-positive bacteria, (2) evaluation of the efficacy of novel agents for infections caused by methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci, and (3) optimization of dosing and duration of antimicrobial agents for gram-positive infections. Herein, we summarize ARLG accomplishments in gram-positive bacterial infection research, including studies aiming to (1) inform optimal vancomycin dosing, (2) determine the role of dalbavancin in MRSA bloodstream infection, (3) characterize enterococcal bloodstream infections, (4) demonstrate the benefits of short-course therapy for pediatric community-acquired pneumonia, (5) develop quality of life measures for use in clinical trials, and (6) advance understanding of the microbiome. Future studies will incorporate innovative methodologies with a focus on interventional clinical trials that have the potential to change clinical practice for difficult-to-treat infections, such as MRSA bloodstream infections.

Bayesian prediction-based individualized dosing of anti-methicillin-resistant Staphylococcus aureus treatment: Recent advancements and prospects in therapeutic drug monitoring

As one of the efficient techniques for TDM, the population pharmacokinetic (popPK) model approach for dose individualization has been developed due to the rapidly growing innovative progress in computer technology and has recently been considered as a part of model-informed precision dosing (MIPD). Initial dose individualization and measurement followed by maximum a posteriori (MAP)-Bayesian prediction using a popPK model are the most classical and widely used approach among a class of MIPD strategies. MAP-Bayesian prediction offers the possibility of dose optimization based on measurement even before reaching a pharmacokinetically steady state, such as in an emergency, especially for infectious diseases requiring urgent antimicrobial treatment. As the pharmacokinetic processes in critically ill patients are affected and highly variable due to pathophysiological disturbances, the advantages offered by the popPK model approach make it highly recommended and required for effective and appropriate antimicrobial treatment. In this review, we focus on novel insights and beneficial aspects of the popPK model approach, especially in the treatment of infectious diseases with anti-methicillin-resistant Staphylococcus aureus agents represented by vancomycin, and discuss the recent advancements and prospects in TDM practice.

Cost analysis of dalbavancin versus standard of care for the treatment of acute bacterial skin and skin structure infections (ABSSSIs) in two Italian hospitals

Objectives

Thanks to its long half-life, dalbavancin qualifies as an optimal drug for saving costs. We aimed to assess the cost and effectiveness of dalbavancin versus the standard of care (SoC).

Patients and methods

We conducted a multicentre retrospective study, including all hospitalized or outpatients diagnosed with ABSSSIs at Padua University Hospital, Padua and San Paolo Hospital, Milan (1 January 2016 to 31 July 2020). We compared patients according to antibiotic treatment (dalbavancin versus SoC), the number of lines of dalbavancin treatment, and monotherapy or combination (dalbavancin in association with other antibiotics). Primary endpoints were direct medical costs and length of hospital stay (LOS) associated with ABSSSI management; Student's t-test, chi-squared test and one-way ANOVA were used.

Results

One hundred and twenty-six of 228 (55.3%) patients received SoC, while 102/228 (44.7%) received dalbavancin. Twenty-seven of the 102 (26.5%) patients received dalbavancin as first-line treatment, 46 (45.1%) as second-line, and 29 (28.4%) as third- or higher-line treatment. Most patients received dalbavancin as monotherapy (62/102; 60.8%). Compared with SoC, dalbavancin was associated with a significant reduction of LOS (5 ± 7.47 days for dalbavancin, 9.2 ± 5.59 days for SoC; P < 0.00001) and with lower mean direct medical costs (3470 ± 2768€ for dalbavancin; 3493 ± 1901€ for SoC; P = 0.9401). LOS was also reduced for first-line dalbavancin, in comparison with second-, third- or higher-line groups, and for dalbavancin monotherapy versus combination therapy. Mean direct medical costs were significantly lower in first-line dalbavancin compared with higher lines, but no cost difference was observed between monotherapy and combination therapy.

Conclusions

Monotherapy with first-line dalbavancin was confirmed as a promising strategy for ABSSSIs in real-life settings, thanks to its property in reducing LOS and saving direct medical costs.

The Safety and Efficacy of Dalbavancin and Active Comparator in Pediatric Patients With Acute Bacterial Skin and Skin Structure Infections

BACKGROUND

Acute bacterial skin and skin structure infections (ABSSSIs) are a significant source of morbidity in children. Dalbavancin, approved for the treatment of adults and children with ABSSSI, has a well-established safety profile in adults. We report safety and descriptive efficacy data for the treatment of ABSSSI in children.

METHODS

Children with ABSSSI (birth-<18 years old) or sepsis (<3 months old) known/suspected to be caused by susceptible Gram-positive organisms were enrolled in this phase 3, multicenter, open-label, comparator-controlled study (NCT02814916). Children ≥3 months old were randomized 3:3:1 to receive single-dose dalbavancin, 2-dose dalbavancin, or a comparator antibiotic in 4 age cohorts; those <3 months old received single-dose dalbavancin. Clinical response and microbiologic efficacy were evaluated 48-72 hours and 14, 28 and 54 days posttreatment. Bowel flora testing and audiology were collected in a subset of patients at baseline and day 28. Adverse events (AEs) were collected throughout the study.

RESULTS

Treatment-emergent AEs occurred in 7.2%, 9.0% and 3.3% of patients in dalbavancin single-dose, dalbavancin 2-dose and comparator arms, respectively. Three serious AEs occurred in the dalbavancin single-dose arm; no treatment-related AEs, serious AEs, or AEs leading to study discontinuation were reported. Favorable clinical response at 48-72 hours was documented in 97.4%, 98.6% and 89.7% of patients. Safety and efficacy were comparable across age cohorts. The microbiologic intent-to-treat population had comparable clinical response for all baseline pathogens, including methicillin-resistant Staphylococcus aureus .

CONCLUSION

The safety profile of dalbavancin was consistent in children and adults with ABSSSI. No new safety signals were identified.

REDS study: Retrospective effectiveness study of dalbavancin and other standard of care of the same IV antibiotic class in patients with ABSSSI

OBJECTIVES

Acute bacterial skin and skin-structure infections (ABSSSIs) are a common source of morbidity in both the community and hospital settings. The current standard of care (SoC) requires multiple-dose intravenous (IV) regimens, which are associated with high hospitalisation rates, concomitant event risks and costs. Dalbavancin is a lipoglycopeptide, long-acting antibiotic that is effective against Gram-positive microorganisms, including methicillin-resistant Staphylococcus aureus (MRSA). Dalbavancin allows treatment of ABSSSIs with a single-shot IV administration or once weekly for 2 weeks, enabling clinicians to treat patients in an outpatient setting or to shorten the length of hospital stay.

METHODS

This multicentre, observational, retrospective study compared hospitalised patients who received dalbavancin and patients treated with the three most used IV antibiotics of the same or similar class: vancomycin, teicoplanin and daptomycin. The primary outcome was the time to discharge after starting the study antibiotics.

RESULTS

The primary endpoint, time to discharge from the study therapy start, was measured for both groups: the median number of days was 6.5 in the dalbavancin group vs. 11.0 days in the SoC group. Moreover, in subpopulations of patients receiving one or more concomitant antibiotics active for Gram-positives, MRSA and patients with the most prevalent comorbidity (i.e., diabetes), the advantage of dalbavancin in terms of length of stay was confirmed, with a halved time to discharge or more. Safety data on dalbavancin were consistent with data collected in clinical trials. No serious adverse drug reactions related to dalbavancin were reported and most of them were classified as skin and subcutaneous tissue disorders. One serious ADR was reported for daptomycin.

CONCLUSIONS

Although the analysis was only descriptive, it can be concluded that dalbavancin may enable a remarkable reduction in length of hospital stay, also confirming the clinical effectiveness and good safety profile demonstrated in clinical trials in a real-world setting.

Population Pharmacokinetic and Pharmacokinetic/Pharmacodynamic Target Attainment Analyses for Dalbavancin in Pediatric Patients

BACKGROUND

Dalbavancin, approved for the treatment of pediatric and adult patients with acute bacterial skin and skin structure infections, has a terminal half-life of >14 days allowing administration as a single-dose regimen.

METHODS

We developed a population pharmacokinetic (PK) model using 1124 dalbavancin concentrations from 211 pediatric patients, with allometric scaling of clearance and volume parameter exponents fixed at 0.75 and 1, respectively. Serum albumin was included as a covariate on all PK parameters; creatinine clearance or estimated glomerular filtration rate was a covariate on clearance. The final model, qualified by visual predictive checks and bootstrapping, was used to simulate 1000 PK profiles for a range of pediatric age groups. PK/pharmacodynamic target attainment (PTA) was calculated for targets associated with stasis, 1-log kill, and 2-log kill of Staphylococcus aureus (neutropenic murine thigh infection model).

RESULTS

Dalbavancin PK was well characterized by a three-compartment model. No additional significant covariates were identified. Simulations showed that single-dose (30-minute intravenous infusion) regimens of 22.5 mg/kg (patients <6 years) and 18 mg/kg (patients 6 years to <18 years) resulted in PTA ≥94% for minimal inhibitory concentrations ≤2 mg/L and ≤0.5 mg/L for the stasis and 2-log kill targets, respectively. PTA for pediatric patients was similar to adults with exposures within the range for adults administered 1500 mg dalbavancin.

CONCLUSION

Dalbavancin PK in pediatric patients was well characterized by a three-compartment model. Simulations with the final model demonstrated adequate PTA across the entire age range for the approved pediatric dalbavancin doses.

Emerging resistance in Staphylococcus epidermidis during dalbavancin exposure: a case report and in vitro analysis of isolates from prosthetic joint infections

BACKGROUND

Dalbavancin, a semisynthetic lipoglycopeptide with exceptionally long half-life and Gram-positive spectrum, is an attractive option for infections requiring prolonged therapy, including prosthetic joint infections (PJIs).

OBJECTIVES

To investigate the prevalence of reduced susceptibility to dalbavancin in a strain collection of Staphylococcus epidermidis from PJIs, and to investigate genomic variation in isolates with reduced susceptibility selected during growth under dalbavancin exposure.

METHODS

MIC determination was performed on S. epidermidis isolates from a strain collection (n = 64) and from one patient with emerging resistance during treatment (n = 4). These isolates were subsequently cultured on dalbavancin-containing agar and evaluated at 48 h; MIC determination was repeated if phenotypical heterogeneity was detected during growth. Population analysis profile (PAP-AUC) was performed in isolates where a  ≥ 2-fold increase in MIC was detected, together with corresponding parental isolates (n = 21). Finally, WGS was performed.

RESULTS

All strains grew at 48 h on agar containing 0.125 mg/L dalbavancin. PAP-AUC demonstrated significant differences between parental and derived strains in four of the eight analysed groups. An amino acid change in the walK gene coinciding with emergence of phenotypic resistance was detected in the patient isolates, whereas no alterations were found in this region in the in vitro derived strains.

CONCLUSIONS

Exposure to dalbavancin may lead to reduced susceptibility to dalbavancin through either selection of pre-existing subpopulations, epigenetic changes or spontaneous mutations during antibiotic exposure. Source control combined with adequate antibiotic concentrations may be important to prevent emerging reduced susceptibility during dalbavancin treatment.

Novel dalbavancin-PLLA implant coating prevents hematogenous Staphylococcus aureus infection in a minimally invasive mouse tail vein model

Infective/bacterial endocarditis is a rare but life-threatening disease with a hospital mortality rate of 22.7% and a 1-year mortality rate of 40%. Therefore, continued research efforts to develop efficient anti-infective implant materials are of the utmost importance. Equally important is the development of test systems that allow the performance of new materials to be comprehensively evaluated. In this study, a novel antibacterial coating based on dalbavancin was tested in comparison to rifampicin/minocycline, and the suitability of a recently developed mouse tail vein model for testing the implant coatings was validated. Small polymeric stent grafts coated with a poly-L-lactic acid (PLLA) layer and incorporated antibiotics were colonized with Staphylococcus (S.) aureus before implantation into the tail vein of mice. The main assessment criteria were the hematogenous spread of the bacteria and the local tissue reaction to the contaminated implant. For this purpose, colony-forming units (CFU) in the blood, spleen and kidneys were determined. Tail cross sections were prepared for histological analysis, and plasma cytokine levels and expression values of inflammation-associated genes were examined. Both antibiotic coatings performed excellently, preventing the onset of infection. The present study expands the range of available methods for testing the anti-infectivity of cardiovascular implants, and the spectrum of agents for effective surface coating.

Acute Bacterial Skin and Skin-Structure Infections, efficacy of Dalbavancin: a systematic review and meta-analysis

OBJECTIVES

To know the efficacy of different doses of dalbavancin in acute bacterial skin and skin-structure infections (ABSSSIs) and versus other antibiotics.

METHODS

We performed a systematic review of dalbavancin efficacy for ABSSSIs. We selected 10 clinical trials from MEDLINE and Cochrane databases for qualitative review. Of these, five trials compared one or two doses of dalbavancin versus other antibiotics such as vancomycin or linezolid.

RESULTS

Treatment outcomes with other antibiotics were not significantly different versus two doses of dalbavancin (OR 1.13; 95% CI 0.75-1.71; p = 0.55) or single dose dalbavancin (OR 0.98; 95% CI 0.19-5.17; p = 0.98). One dose versus two doses of dalbavancin did not show significant differences in any of the treatment groups. In contrast, the global microbiological assessment results indicated a favorable outcome for two doses of dalbavancin compared to the single dose of dalbavancin (OR 2.96; 95% CI 1.19-7.39; p = 0.02) in both methicillin-resistant and methicillin-susceptible Staphylococcus aureus.

CONCLUSION

Either single dose or two dose dalbavancin treatment is as clinically effective as other antibiotics such as vancomycin and linezolid for the treatment of ABSSSIs.Abbreviations ABSSI: acute bacterial skin and skin-structure infection; AUC: area under the concentration-time curve; CE: clinical evaluable; CI: confidence interval; EOT: end of treatment; ITT: intention-to-treat; LOS: length of stay; MIC: minimum inhibitory concentration; MIC₉₀: minimum concentration to inhibit growth of 90% of isolates; MR: methicillin resistant; MRSA: methicillin-resistant Staphylococcus aureus; MS: methicillin susceptible; MSSA: methicillin-susceptible Staphylococcus aureus; OPAT: Outpatient Parenteral Antimicrobial Therapy; OR: odds ratio; PI: penicillin intermediate; PR: penicillin resistant; PS penicillin susceptible; SIRS: systemic inflammatory response syndrome; SSTI: skin and soft tissue infection; TOC: test of cure; VR: vancomycin resistant; VS: vancomycin susceptible.

Dalbavancin in the treatment of acute bacterial skin and skin structure and other infections: a safety evaluation

INTRODUCTION

Dalbavancin is a second-generation lipoglycopeptide that was approved since 2014 to treat acute bacterial skin and skin-structure infections (ABSSSI). Dalbavancin is characterized by Gram-positive activity and novel pharmacokinetic properties that result in a prolonged terminal half-life, allowing once weekly dosing in adults. A good safety profile was reported by randomized clinical trials and meta-analyses.

AREAS COVERED

Dalbavancin safety and tolerability data from trials and post-marketing studies were reviewed. While most trials included predominantly ABSSSI, 2 clinical trials and recent observational studies have explored the use of dalbavancin for off-label indications, mainly including bloodstream and osteoarticular infections.

EXPERT OPINION

The occurrence of drug-related adverse effects (AE) was similar between dalbavancin and comparators in clinical trials enrolling patients with ABSSSI. Most common AE included gastrointestinal symptoms, infusion reaction, and hypersensitivity. Low rates of drug discontinuation and serious AE were reported across studies. In the past 5 years, several observational studies have reported safety data on the use of dalbavancin, confirming its favorable safety profile. Nevertheless, data from dalbavancin off-label use often derived from prolonged (> 2 weeks) treatments with variable dosing regimens, were mainly retrospective, and lacked comparators. Further research is required to allow a reliable analysis of short- and long-term dalbavancin-related AE in non-ABSSSI.

Antibiotic resistance in dermatology: The scope of the problem and strategies to address it

Antibiotic resistance is a growing health concern that has attracted increasing attention from clinicians and scientists in recent years. Although resistance is an inevitable consequence of bacterial evolution and natural selection, misuse and overuse of antibiotics play a significant role in its acceleration. Antibiotics are the mainstay of therapy for common dermatoses, including acne and rosacea, as well as for skin and soft tissue infections. Therefore, it is critical for dermatologists and physicians across all disciplines to identify, appropriately manage, and prevent cases of antibiotic resistance. This review explores dermatologic conditions in which the development of antibiotic resistance is a risk and discusses mechanisms underlying the development of resistance. We discuss disease-specific strategies for overcoming resistant strains and improving antimicrobial stewardship along with recent advances in the development of novel approaches to counter antibiotic resistance.

Dalbavancin as an option for treatment of S. aureus bacteremia (DOTS): study protocol for a phase 2b, multicenter, randomized, open-label clinical trial

Background

Staphylococcus aureus bacteremia is a life-threatening infection and leading cause of infective endocarditis, with mortality rates of 15–50%. Treatment typically requires prolonged administration of parenteral therapy, itself associated with high costs and potential catheter-associated complications. Dalbavancin is a lipoglycopeptide with potent activity against Staphylococcus and a long half-life, making it an appealing potential therapy for S. aureus bacteremia without the need for durable central venous access.

Methods

DOTS is a phase 2b, multicenter, randomized, assessor-blinded, superiority, active-controlled, parallel-group trial. The trial will enroll 200 adults diagnosed with complicated S. aureus bacteremia, including definite or possible right-sided infective endocarditis, who have been treated with effective antibiotic therapy for at least 72 h (maximum 10 days) and with subsequent clearance of bacteremia prior to randomization to study treatment. Subjects will be randomized 1:1 to complete their antibiotic treatment course with either two doses of dalbavancin on days 1 and 8, or with a total of 4–8 weeks of standard intravenous antibiotic therapy. The primary objective is to compare the Desirability of Outcome Ranking (DOOR) at day 70 for patients randomized to dalbavancin versus standard of care. Key secondary endpoints include quality of life outcomes and pharmacokinetic analyses of dalbavancin.

Discussion

The DOTS trial will establish whether dalbavancin is superior to standard parenteral antibiotic therapy for the completion of treatment of complicated S. aureus bacteremia.

Trial registration

US National Institutes of Health ClinicalTrials.govNCT04775953. Registered on 1 March 2021

Role of Extracellular DNA in Dalbavancin Activity against Methicillin-Resistant Staphylococcus aureus (MRSA) Biofilms in Patients with Skin and Soft Tissue Infections

Methicillin-resistant Staphylococcus aureus (MRSA) has become the leading cause of skin and soft tissue infections (SSTIs). Biofilm production further complicates patient treatment, contributing to increased bacterial persistence and antibiotic tolerance. The study aimed to explore the efficacy of different antibiotics on biofilm-producing MRSA isolated from patients with SSTI. A total of 32 MRSA strains were collected from patients with SSTI. The MIC and minimal biofilm eradication concentration (MBEC) were measured in planktonic and biofilm growth. The study showed that dalbavancin, linezolid, and vancomycin all inhibited MRSA growth at their EUCAST susceptible breakpoint. Of the MRSA strains, 87.5% (n = 28) were strong biofilm producers (SBPs), while only 12.5% (n = 4) were weak biofilm producers (WBPs). The MBEC90 values for dalbavancin were significantly lower than those of linezolid and vancomycin in all tested strains. We also found that extracellular DNA (eDNA) contributes to the initial microbial attachment and biofilm formation. The amount of eDNA differed among MRSA strains and was significantly higher in those isolates with high dalbavancin and vancomycin tolerance. Exogenously added DNA increased the MBEC90 and protection of biofilm cells from dalbavancin activity. Of note, the relative abundance of eDNA was higher in MRSA biofilms exposed to MBEC90 dalbavancin than in untreated MRSA biofilms and those exposed to sub-MIC90. Overall, dalbavancin was the most active antibiotic against MRSA biofilms at concentrations achievable in the human serum. Moreover, the evidence of a drug-related increase of eDNA and its contribution to antimicrobial drug tolerance reveals novel potential targets for antibiofilm strategies against MRSA. IMPORTANCE Staphylococcus aureus is the most common cause of skin and soft tissue infections (SSTIs) worldwide. In addition, methicillin-resistant S. aureus (MRSA) is increasingly frequent in postoperative infections and responsible for a large number of hospital readmissions and deaths. Biofilm formation by S. aureus is a primary risk factor in SSTIs, due to a higher antibiotic tolerance. Our study showed that the biofilm-forming capacity varied among MRSA strains, although strong biofilm producers were significantly more abundant than weak biofilm producer strains. Notably, dalbavancin demonstrated a potent antibiofilm activity at concentrations achievable in human serum. Nevertheless, dalbavancin activity was affected by an increased concentration of extracellular DNA in the biofilm matrix. This study provides novel insight for designing more targeted therapeutic strategies against MRSA and to prevent or eradicate harmful biofilms.

A Multicentre, Prospective, and Retrospective Registry to Characterize the Use, Effectiveness, and Safety of Dalbavancin in German Clinical Practice

The antibiotic dalbavancin is approved for intravenous treatment of adults with acute bacterial skin and skin structure infections. This study aimed to observe the use, effectiveness, and safety of dalbavancin in clinical practice in Germany. It was a multicentre, prospective, and retrospective registry and consecutively enrolled patients treated with dalbavancin. Each patient was observed from the first to the last dose of dalbavancin, with a 30-day follow-up. Patient inclusion was planned for 2 years, but was terminated early due to low recruitment. All analyses were descriptive. Between November 2018 and December 2019, nine patients were enrolled. Only three patients were treated for the approved indication. Outcome was assessed by the physicians as ‘success’ in five (55.6%) patients, ‘failure’ in one (11.1%) patient, and non-evaluable in three (33.3%) patients. Although the success rate of dalbavancin was lower than reported previously, this may be due to the severity of underlying infections and patients’ high Charlson Comorbidity Index. None of the two reported adverse events were considered related to dalbavancin. These findings were in line with real-world data for dalbavancin from other countries, supporting the drug’s positive benefit–risk profile and suggesting frequent off-label use in German routine practice.

Cyclic peptide drugs approved in the last two decades (2001-2021)

In contrast to the major families of small molecules and antibodies, cyclic peptides, as a family of synthesizable macromolecules, have distinct biochemical and therapeutic properties for pharmaceutical applications. Cyclic peptide-based drugs have increasingly been developed in the past two decades, confirming the common perception that cyclic peptides have high binding affinities and low metabolic toxicity as antibodies, good stability and ease of manufacture as small molecules. Natural peptides were the major source of cyclic peptide drugs in the last century, and cyclic peptides derived from novel screening and cyclization strategies are the new source. In this review, we will discuss and summarize 18 cyclic peptides approved for clinical use in the past two decades to provide a better understanding of cyclic peptide development and to inspire new perspectives. The purpose of the present review is to promote efforts to resolve the challenges in the development of cyclic peptide drugs that are more effective.

Clinical Pharmacokinetics and Pharmacodynamics of Dalbavancin

Dalbavancin is a synthetic lipoglycopeptide that exerts its antimicrobial activity through two distinct modes of action, inhibition of cell wall synthesis and an anchoring mechanism. Compared with previous glycopeptide antibiotics, dalbavancin demonstrates improved antibacterial potency against Gram-positive organisms and a long half-life of approximately 1 week, which is longer in tissues (e.g., skin, bone) than plasma. These factors facilitated the development of single-dose or once-weekly dosing regimens to treat acute bacterial skin and skin structure infections (ABSSSI). Dalbavancin exhibits dose-proportional pharmacokinetics and is highly protein bound (93%). Despite being highly protein bound, it has a steady-state volume of distribution >10 L and distributes widely into the skin, bone, peritoneal space, and epithelial lining fluid, but not cerebrospinal fluid. Dalbavancin elimination occurs via a combination of renal (approximately 45%) and non-renal clearance, with dose adjustments recommended only in patients with a creatinine clearance <30 mL/min not receiving any form of dialysis. The established pharmacokinetic/pharmacodynamic index associated with bacterial kill is free area under the concentration-time curve over the minimum inhibitory concentration (fAUC/MIC), with a goal 24-h fAUC/MIC of at least 27.1 for Staphylococcus aureus infections. Recent data suggest usefulness in the treatment of infections beyond ABSSSI, with convenient dosing and redosing strategies for complicated infections requiring extended treatment durations. Additional studies are needed to confirm these preliminary findings.

Clinical efficacy and safety of novel lipoglycopeptides in the treatment of acute bacterial skin and skin structure infections: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

This systematic review and meta-analysis aimed to investigate the clinical efficacy and safety of novel lipoglycopeptides in treating acute bacterial skin and skin structure infections (ABSSSIs).

RESEARCH DESIGN AND METHODS

PubMed, Embase, Cochrane Central Register of Controlled Trials, Turning Research into Practice, and ClinicalTrials.gov were searched from inception to 20 May 2021. Randomized controlled trials (RCTs) comparing the clinical efficacy and safety of lipoglycopeptides with other comparators in treating adult patients with ABSSSIs were included. The primary outcome was clinical response.

RESULTS

Eight RCTs (6416 patients; lipoglycopeptides: 3359, comparators: 3057) were enrolled. Clinical response rate was not significantly different between lipoglycopeptides and comparators at early-clinical-evaluation (odds ratio [95% confidence interval]: 1.01 [0.85-1.20], I² = 34%), end-of-treatment (0.94 [0.80-1.11], I² = 0%), and test-of-cure (1.05 [0.85-1.30], I² = 0%). Lipoglycopeptides showed a similar overall microbiological eradication rate (1.12 [0.90-1.38], I² = 21%) but a borderline higher microbiological eradication rate for methicillin-resistant Staphylococcus aureus (1.37 [1.00-1.86], I² = 0%) than the comparators. Lipoglycopeptides were not associated with a higher risk than comparators.

CONCLUSIONS

Lipoglycopeptides can achieve similar clinical and microbiological responses to other comparators in treating ABSSSIs. In addition, lipoglycopeptides are as tolerable as their comparators.

Use of Dalbavancin in Skin, Bone and Joint Infections: A Real-Life Experience in an Italian Center

Dalbavancin is a lipoglycopeptide approved for the treatment of acute bacterial skin and skin structure infections (ABSSSI). The aim of the study was to evaluate the efficacy and safety in all patients who received at least one administration of dalbavancin.

METHODS

We carried out a retrospective study of the use of dalbavancin in 55 patients at the Azienda Ospedaliera Ospedali Riuniti Umberto I (Ancona, Italy) from February 2017 to May 2020 and compared "on label" and "off label" use of dalbavancin in ABSSSI and non-ABSSSI.

RESULTS

A total of 55 patients were included in the study. The median age was 61 years; 51% had ABSSSI; 24% had prosthetic joint infections, and 14% had osteomyelitis. A total of 53% received a single 1500 mg infusion of dalbavancin, and 18% received a second dose 14 days later; 24% of patients received further doses at 14-day intervals. In 91% of cases, patients achieved clinical objectives with dalbavancin: 96% of patients with ABSSSI and 69% of those with prosthetic joint infections.

CONCLUSIONS

Dalbavancin was shown to have an excellent tolerability profile and to be a highly successful therapeutic approach even in those cases treated "off-label".

Role or oritavancin and dalbavancin in acute bacterial skin and skin structure infections and other potential indications

PURPOSE OF REVIEW

To discuss the currently available evidence about the use oritavancin and dalbavancin for the treatment of acute bacterial skin and skin structure infections (ABSSSI) and for other potential indications.

RECENT FINDINGS

In this review, we briefly summarize the available data on efficacy (from randomized controlled trials) and on effectiveness and cure rates (from observational studies) pertaining to the use of oritavancin and dalbavancin either for ABSSSI or for other indications.

SUMMARY

Oritavancin and dalbavancin are valid options for outpatient therapy and early discharge in patients with ABSSSI, especially when adherence to oral therapy cannot be guaranteed or no oral choices are available. Furthermore, it is worth noting that a non-negligible portion (sometimes the majority) of oritavancin and dalbavancin use in available real-life experiences is for indications other than ABSSSI, especially for Gram-positive osteomyelitis and endocarditis. The number of studies on the use of long-acting lipoglycopeptides for these currently off-label indications is rapidly increasing and will help to further optimize the use of these peculiar antibiotics in the forthcoming future.

Systematic review and meta-analysis on the safety of dalbavancin

BACKGROUND

Dalbavancin is a semisynthetic lipoglycopeptide antimicrobial agent with activity against Gram-positive bacteria including anaerobes.

RESEARCH DESIGN AND METHODS

Meta-analysis of randomized control trials and large case series (more than 20 patients), were identified by searching Pubmed and Cochrane databases through 14 December 2020.

RESULTS

3,073 patients from 6 RCTs met the inclusion criteria. Treatment emergent adverse effects were described in 30.6% dalbavancin patients, and 38.1% patients with other treatments. Our meta-analysis supports favorable results for dalbavancin treatment (OR 0.79; 95%CI 0.66-0.94; p = 0.01). 2.74% dalbavancin patients had to discontinue treatment versus 2.49% patients on other antibiotics. 4.80% dalbavancin patients versus 5.30% patients with other treatments had severe adverse events. 0.31% in the dalbavancin group and 0.95% receiving other antibiotics died. There was no statistically significant difference in severe adverse effects with OR 0.77; 95% CI 0.52-1.14; p = 0.19. Dalbavancin therapy was shown to have statistically significant lower mortality rate (OR 0.26; 95% CI 0.07-0.90; p = 0.03). Observational studies reported few side effects but included a heterogeneous population of patients concerning their diagnosis and the duration of antibiotic treatment.

CONCLUSIONS

Dalbavancin has comparable safety profile relative to other antibiotics and is well-tolerated.

Review: A Safety Profile of Dalbavancin for On- and Off-Label Utilization

Introduction

Dalbavancin is a bactericidal lipoglycopeptide active against gram-positives. Its use has been approved for the treatment of acute bacterial skin and skin structure infections (ABSSSI).

Methods

We conducted a narrative review of the literature on the safety profile of dalbavancin. The bibliographic research was carried out on the PubMed database on 6 November 2020 by seeking combinations of the following keywords: dalbavancin, adverse effects, safety, drug interactions, and skin infections.

Results

Five double-blind Phase 3 randomized clinical trials, 2 open-label randomized trials, and 4 retrospective studies were identified. No statistically significant differences were found between dalbavancin and comparators in the incidence of adverse events. Retrospective studies confirm the low incidence of adverse events.

Conclusion

Dalbavancin is a therapeutic option that has demonstrated an excellent safety profile, also in relation to the other MRSA therapies available. Its use represents a cost-effective solution for the treatment of those patients with ABSSSI who would need hospitalization. One limitation of this study is that most of the available data are from Phase III clinical trials. Further real-life studies with a larger sample size are therefore needed to better assess the safety profile of the dalbavancin, especially to investigate the true incidence of rare adverse events.

Efficacy and safety of dalbavancin in the treatment of Gram-positive bacterial infections

OBJECTIVES

In this meta-analysis, we assessed the clinical efficacy and safety of dalbavancin compared with commonly used anti-Gram-positive agents.

METHODS

PubMed, Embase and Cochrane Library databases were searched from inception up to 25 February 2020. Randomised controlled trials (RCTs) comparing the efficacy and safety of dalbavancin with other antibiotics against Gram-positive infections were included. Reviews, conference abstracts, editorials, case reports, studies on healthy people, or those lacking a comparator group or focusing on different dosages were excluded.

RESULTS

Seven RCTs comprising 2665 patients were included. Five RCTs included 2109 patients with skin and skin-structure infections (SSSIs) and the other two included patients with catheter-related bloodstream infections (CRBSIs) and osteomyelitis, respectively. Clinical and microbiological responses to dalbavancin were similar to other antibiotics in treating infections caused by Gram-positive bacteria, including the SSSI subgroup. Clinical response to dalbavancin showed superiority in the CRBSI and osteomyelitis subgroups. No significant difference was observed between dalbavancin and other treatments in terms of adverse events (AEs), adverse drug reactions (ADRs) and serious AEs. However, the single-dose regimen had significantly more AEs compared with the comparator group, while the dual-dose regimen resulted in fewer AEs and ADRs and a lower incidence of diarrhoea compared with the comparator group. Moreover, the dalbavancin group showed a decreased mortality risk compared with other treatments.

CONCLUSION

Dalbavancin was comparable with other antibiotics in treating chronic Gram-positive infections in terms of efficacy and safety. The dual-dose regimen showed a better safety profile compared with the single-dose regimen in the treatment of SSSIs.

In Vitro Study To Evaluate the Bioactivity of Freezing a Heparin-Based Dalbavancin Lock Solution

The use of dalbavancin as a catheter lock solution must be addressed in depth before implementation in clinical practice. We assessed whether a heparin-based dalbavancin lock solution could be frozen in single-dose vials for 6 months without affecting its bioactivity against biofilms of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE). Over 6 months, we tested the bioactivity of a frozen solution of dalbavancin (≈1 mg/ml) plus heparin (60 IU) in terms of CFU counts and metabolic activity against biofilms of Staphylococcus aureus ATCC 43300 (MRSA) and Staphylococcus epidermidis ATCC 35984 (MRSE). The Anti-Xa assay was also performed to assess whether the anticoagulant activity of heparin was reduced under freezing. Every month, we compared the mean value of each variable with that obtained at baseline (before freezing, month 0) using both clinical criteria (values were within 25% of the baseline value) and statistical criteria (linear mixed models). At the end of the experiment (month 6), neither a clinically nor a statistically significant reduction in the bioactivity of dalbavancin-heparin solution was observed in terms of CFU counts and metabolic activity against biofilm of MRSA. Regarding MRSE, considering the clinical criteria, neither CFU counts nor metabolic activity decreased significantly. However, the reduction was statistically significant for all variables. Anti-Xa values (mean [standard deviation] international units per milliliter) for heparin in combination with dalbavancin were within 25% of the heparin-water value. A heparin-based dalbavancin lock solution can be frozen for up to 6 months with no effect on its bioactivity against MRSA and MRSE biofilms.

Dalbavancin in the Treatment of Bacteremia and Endocarditis in People with Barriers to Standard Care

Introduction: Dalbavancin is an antibiotic administered by intravenous infusion weekly or bi-weekly and is currently FDA-approved only for treatment of skin and soft-tissue infections. It has shown promise, but is not considered the standard of care, for bacteremia and infective endocarditis (IE), which typically require outpatient parenteral antibiotic therapy (OPAT) for prolonged durations. People who inject drugs (PWID) with bacteremia or IE are often perceived as having barriers to OPAT and standard daily-administered antibiotics, prompting off-label use of dalbavancin in this population. Methods: A retrospective review of adult patients receiving at least one dose of dalbavancin for bacteremia or IE was conducted between 1 November 2017 and 31 October 2019. Outcomes and reasons for use of dalbavancin were recorded, including specific barriers to standard therapy. Results: Stated reasons for dalbavancin use in the 18 patients identified included active injection drug use (50%), inability to arrange standard OPAT due to patient adherence or inability to place in skilled nursing facility (SNF) (22%), risk for additional infections or other morbidity with OPAT (22%), and patient preference (6%). In 11 patients (61%) SNF placement was not attempted due to behavioral issues or patient declination. There were five patients who did not complete their intended course of treatment (28%). At 90 days, eight patients (44%) achieved a clinical or biologic cure, six (33%) failed treatment, and four (22%) were lost to follow-up. Conclusion: Dalbavancin may have a role as salvage therapy in the treatment of IE and bacteremia in PWID who have significant barriers to standard treatment.

Efficacy and safety of dalbavancin in the treatment of acute bacterial skin and skin structure infections (ABSSSIs) and other infections in a real-life setting: data from an Italian observational multicentric study (DALBITA study)

OBJECTIVES

We evaluated the efficacy and safety of dalbavancin in ABSSSI and 'other sites' infections' (OTA).

METHODS

Observational study involving 11 Italian hospitals including patients that received ≥1 dose of dalbavancin in 2016-2019. The outcome was end-of-treatment efficacy and safety in ABSSSI and OTA in a real-life setting.

RESULTS

206 patients enrolled (males 50%, median age 62 [IQR 50-76] years), 60.2% ABSSSI, 39.8% OTA. 69.7% ABSSSI vs 90.7% OTA (p = 0.003) and 46.3% ABSSSI vs 37.2% OTA (p = 0.786) received previous and concomitant antibiotics, respectively. 82.5% reached clinical cure . Eleven (5.4%) patients had non-serious adverse events (AE). OTA patients showed longer hospitalization (13.5 days, 5.5-22 vs 3, 0-11.7; p<0.0001) and received longer previous (18 days, 9-30 vs 11, 7-19; p = 0.007)/concomitant antibiotic treatments (21 days, 14-52 vs 11, 8-14; p < 0.0001), compared to ABSSSI. ABSSSI and OTA showed similar efficacy (85.5% vs 75%, p = 0.459) and safety (no AE: 81.5% vs 64.3%, p = 0.258); efficacy was independent of previous/concomitant therapies.

CONCLUSIONS

Dalbavancin demonstrated a success rate of >80%, with similar efficacy/safety in ABSSSI and off-label indications. The preferential use of dalbavancin as second-line or combination therapy would seem to suggest the need for in-depth studies focused on its off-label use.

Current Treatment Options for Acute Skin and Skin-structure Infections

Acute bacterial skin and skin-structure infections (ABSSSIs) are a common reason for seeking care at acute healthcare facilities, including emergency departments. Staphylococcus aureus is the most common organism associated with these infections, and the emergence of community-associated methicillin-resistant Staphylococcus aureus (MRSA) has represented a considerable challenge in their treatment. To address this need, a number of new antibiotics have been developed for the treatment of ABSSSIs in the past several years. Most of these agents focus primarily on gram-positive organisms, particularly MRSA; however, there has not been an oral agent that can reliably treat MRSA, as well as relevant gram-negative pathogens. Acute skin infections that involve mixed gram-positive and gram-negative pathogens must also be considered as they can be associated with discordant antimicrobial therapy. Here, I review ABSSSI treatment guidelines in the hospital setting and discuss current and future antibiotic options for treatment of this commonly encountered infection.

Effect of Dalbavancin on Staphylococcal Biofilms When Administered Alone or in Combination With Biofilm-Detaching Compounds

Microorganisms grown in biofilms are more resistant to antimicrobial treatment and immune system attacks compared to their planktonic forms. In fact, infections caused by biofilm-forming Staphylococcus aureus and Staphylococcus epidermidis are a large threat for public health, including patients with medical devices. The aim of the current manuscript was to test the effect of dalbavancin, a recently developed lipoglycopeptide antibiotic, alone or in combination with compounds contributing to bacterial cell disaggregation, on staphylococcal biofilm formation and elimination. We used real-time impedance measurements in microtiter plates to study biofilm growth dynamics of S. aureus and S. epidermidis strains, in the absence or presence of dalbavancin, linezolid, vancomycin, cloxacillin, and rifampicin. Further experiments were undertaken to check whether biofilm-detaching compounds such as N-acetylcysteine (NAC) and ficin could enhance dalbavancin efficiency. Real-time dose–response experiments showed that dalbavancin is a highly effective antimicrobial, preventing staphylococcal biofilm formation at low concentrations. Minimum biofilm inhibitory concentrations were up to 22 higher compared to standard E-test values. Dalbavancin was the only antimicrobial that could halt new biofilm formation on established biofilms compared to the other four antibiotics. The addition of NAC decreased dalbavancin efficacy while the combination of dalbavancin with ficin was more efficient than antibiotic alone in preventing growth once the biofilm was established. Results were confirmed by classical biofilm quantification methods such as crystal violet (CV) staining and viable colony counting. Thus, our data support the use of dalbavancin as a promising antimicrobial to treat biofilm-related infections. Our data also highlight that synergistic and antagonistic effects between antibiotics and biofilm-detaching compounds should be carefully tested in order to achieve an efficient treatment that could prevent both biofilm formation and disruption.

Calculated initial parenteral treatment of bacterial infections: Skin and soft tissue infections

This is the ninth chapter of the guideline "Calculated Parenteral Initial Therapy of Adult Bacterial Disorders - Update 2018" in the 2nd updated version. The German guideline by the Paul-Ehrlich-Gesellschaft für Chemotherapie e.V. (PEG) has been translated to address an international audience. The chapter contains the first German S2k guidelines for bacterial skin and soft tissue infections. They encompass recommendations on diagnosis and treatment of the defined entities erysipelas (caused by beta-hämolytic streptococci), limited superficial cellulitis (S. aureus), severe cellulitis, abscess, complicated skin and soft tissue infections, infections of feet in diabetic patients ("diabetic foot"), necrotizing soft tissue infection and bite injuries.

S2k guidelines for skin and soft tissue infections Excerpts from the S2k guidelines for "calculated initial parenteral treatment of bacterial infections in adults - update 2018"

These first German S2k guidelines for bacterial skin and soft tissue infections were developed as one chapter of the recommendations for "calculated initial parenteral treatment of bacterial infections" issued under the auspices of the Paul-Ehrlich Society, of which the main part is presented here. Well-calculated antibiotic therapies require precise diagnostic criteria. Erysipelas is defined as non-purulent infection considered to be caused by beta-hemolytic strepto-cocci. It is diagnosed clinically by its bright-red erythema and early fever or chills at disease onset. Penicillin is the treatment of choice. Limited soft tissue infection (cellulitis) is usually caused by Staphylococcus (S.) aureus, frequently originates from chronic wounds and presents with a more violaceous-red hue and only rarely with initial fever or chills. Treatment consists of first- or second--generation cephalosporins or flucloxacillin (IV). Severe cellulitis is a purulent, partially necrotic infection which extends through tissue boundaries to fascias and requires surgical management in addition to antibiotics. Moreover, it frequently fulfills the criteria for "complicated soft tissue infections", as previously defined by the Food and Drug Administration for use in clinical trials (they include comorbidities such as uncontrolled diabetes, peripheral artery disease, neutropenia). It requires antibiotics which besides S. aureus target anaerobic and/or gramnegative bacteria. The rare so-called necrotizing skin and soft tissue infections represent a distinct entity. They are characterized by rapid, life-threatening progression due to special bacterial toxins that cause ischemic necrosis and shock and need rapid and thorough debridement in addition to appropriate antibiotics. For cutaneous abscesses the first-line treatment is adequate drainage. Additional antibiotic therapy is required only under certain circumstances (e.g., involvement of the face, hands, or anogenital region, or if drainage is somehow complicated). The present guidelines also contain consensus-based recommendations for higher doses of antibiotics than those approved or usually given in clinical trials. The goal is to deliver rational antibiotic treatment that is both effective and well-tolerated and that exerts no unnecessary selection pressure in terms of multidrug resistance.

Can dalbavancin be used as a catheter lock solution?

Purpose. The new lipoglycopeptide dalbavancin has only been approved for acute bacterial skin and skin structure infections. However, its alternative use as a catheter lock solution could facilitate the conservative management of catheter-related bloodstream infection. Our objective was to assess the stability and activity of dalbavancin alone and in combination with heparin against methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE) biofilms. We also compared the results with those obtained with vancomycin alone and in combination with heparin.Methodology. We used a 96-well plate in vitro model based on 24 h biofilms of MRSA and MRSE (ATCC 43300, ATCC 35984 and one clinical strain of each). The biofilms were exposed to dalbavancin (0.128 mg ml^-1) and vancomycin (5 mg ml^-1) alone and in combination with heparin (60 IU). The median percentage reductions in metabolic activity, biomass, bacterial load, and cell viability for each solution were compared.Results. Dalbavancin combined with heparin significantly reduced the median [interquartile range (IQR)] percentage of metabolic activity in MRSA biofilms compared with vancomycin [90.0 % (70.4-92.9 %) versus 35.0 % (14.8-59.6 %), P=0.006]. For the remaining variables studied, the combination was not inferior to vancomycin for MRSA and MRSE.Conclusions. Dalbavancin proved to be active against MRSA and MRSE biofilms. The combination of dalbavancin with heparin is a promising catheter lock solution that has the advantage of locking the catheter at home for 7 days.

Therapeutic compounds targeting Lipid II for antibacterial purposes

Resistance against commonly used antibiotics has emerged in all bacterial pathogens. In fact, there is no antibiotic currently in clinical use against which resistance has not been reported. In particular, rapidly increasing urbanization in developing nations are sites of major concern. Additionally, the widespread practice by physicians to prescribe antibiotics in cases of viral infections puts selective pressure on antibiotics that still remain effective and it will only be a matter of time before resistance develops on a large scale. The biosynthesis pathway of the bacterial cell wall is well studied and a validated target for the development of antibacterial agents. Cell wall biosynthesis involves two major processes; 1) the biosynthesis of cell wall teichoic acids and 2) the biosynthesis of peptidoglycan. Key molecules in these pathways, including enzymes and precursor molecules are attractive targets for the development of novel antibacterial agents. In this review, we will focus on the major class of natural antibacterial compounds that target the peptidoglycan precursor molecule Lipid II; namely the glycopeptides, including the novel generation of lipoglycopeptides. We will discuss their mechanism-of-action and clinical applications. Further, we will briefly discuss additional peptides that target Lipid II such as the lantibiotic nisin and defensins. We will highlight recent developments and future perspectives.

The role of dalbavancin in skin and soft tissue infections

PURPOSE OF REVIEW

The increase of skin and soft tissue infections (SSTIs) represents a major concern both in community and in the hospital setting. Staphylococcus aureus is the most frequently isolated pathogen, and the rise in infections due to methicillin-resistant Staphylococcus aureus (MRSA) has been associated with inadequate antibiotic treatment and increased morbidity.

RECENT FINDINGS

A number of new antimicrobials with activity against drug-resistant Gram-positive pathogens, including MRSA, have been recently approved for the treatment of SSTIs. New lipoglycopeptides, in particular dalbavancin, are long-acting antibiotics with potential for infrequent administration, offering the possibility for outpatient treatment and early hospital discharge.

SUMMARY

Dalbavancin is a new lipoglycopeptide showing high activity against Gram-positive bacteria, including drug-resistant strains. Dalbavancin presents a distinctive pharmacokinetic profile with a terminal prolonged half-life of approximately 14 days. This characteristic allows once-weekly dosing interval, avoiding the need for daily dosing and offering an advantage over other compounds for potential use in the outpatient setting or to promote early hospital discharge. Dalbavancin has a favorable adverse effect profile and appears to be a promising new alternative for treatment of SSTIs. We have reviewed the pharmacokinetic properties of dalbavancin and the clinical evidence for its use in complicated SSTIs and other potential applications.

Dalbavancin Population Pharmacokinetic Modeling and Target Attainment Analysis

Dalbavancin is indicated for the treatment of acute bacterial skin and skin structure infections caused by susceptible gram-positive microorganisms. This analysis represents the update of the population pharmacokinetics (popPK) modeling and target attainment simulations performed with data from the single-dose safety and efficacy study and an unrelated but substantial revision of the preclinical pharmacokinetic/pharmacodynamic target (fAUC/MIC, free area under concentration-time curve/minimum inhibitory concentration ratio). A 3-compartment distribution model with first-order elimination provided an appropriate fit, with typical dalbavancin clearance of 0.05 L/h and total volume of distribution of ∼15 L. Impact of intrinsic factors was modest, although statistically significant (P < .05) relationships with total clearance were found for the following covariates: creatinine clearance, weight, and albumin - dose adjustment was only indicated for severe renal impairment. Under the new nonclinical target, simulations of the popPK model projected that >99% of subjects would achieve the nonclinical target at MIC values up to and including 2 mg/L.

Current and emerging pharmacotherapy for the treatment of infections following open-heart surgery

INTRODUCTION

Patients undergoing open-heart surgery may suffer from postoperative complications, including severe infections. Antimicrobials to treat infectious complications in this population should be selected thoughtfully, taking into account three different and fundamental issues: (i) the site of infection; (ii) the suspected or proven causative agent and its susceptibility pattern; and (iii) the risk of suboptimal pharmacokinetic characteristics and potential toxicity of the chosen drug/s.

AREAS COVERED

The present narrative review summarizes the current and future antimicrobial options for the treatment of infections developing after open-heart surgery.

EXPERT OPINION

The pharmacological treatment of infections developing in cardiac surgery patients poses peculiar challenges, including the need for an active empirical therapy for severe events such as bloodstream infections, deep sternal wound infections, or early-onset postoperative prosthetic endocarditis. In addition, the risk for multidrug-resistant pathogens should also be taken into account in endemic areas. A multidisciplinary evaluation on a patient-by-patient basis, deeply involving infectious diseases specialists and cardiothoracic surgeons, remains essential for appropriately balancing both short-term and long-term risks and benefits of any possible surgical reintervention in combination with adequate pharmacotherapy.

Multicenter clinical experience of real life Dalbavancin use in gram-positive infections

Dalbavancin, a lipoglycopeptide with prolonged half-life approved for the treatment of acute bacterial skin and soft tissue infections, can be used for the treatment of infections caused by gram-positive bacteria requiring long term treatment such as endocarditis, prosthetic joint infections (PJI) or osteomyelitis. Clinical data are limited in these settings.

OBJECTIVES

To evaluate indications, safety, tolerability and long-term outcomes of dalbavancin-treated patients. Patients and methods Our multicenter, retrospective study includes patients who received dalbavancin in Austria from September 2016 to March 2018. 90-day outcomes and tolerability were determined.

RESULTS

A total of 101 patients were included in 3 centers (57% male, median age 65 years). The treated infections were PJI (31%), osteomyelitis (29%), endocarditis (25%) and acute bacterial skin and soft tissue infections (12%). Concomitant use of other antimicrobial substances was common (63%). The mean total cumulative dose of dalbavancin was 3,357mg (±2,283mg). Clinical success rate was 89%. Side effects occurred in 3/101 patients.

CONCLUSION

In this real-life study dalbavancin was primarily used in off-label indications for treatment of PJI, osteomyelitis and endocarditis. Success rate was high (89%), tolerability and safety were excellent in this setting. Dalbavancin may therefore be used in these off-label indications as alternative treatment approach.

Effects of Microplate Type and Broth Additives on Microdilution MIC Susceptibility Assays

The determination of antibiotic potency against bacterial strains by assessment of their minimum inhibitory concentration normally uses a standardized broth microdilution assay procedure developed more than 50 years ago. However, certain antibiotics require modified assay conditions in order to observe optimal activity.

The determination of antibiotic potency against bacterial strains by assessment of their minimum inhibitory concentration normally uses a standardized broth microdilution assay procedure developed more than 50 years ago. However, certain antibiotics require modified assay conditions in order to observe optimal activity. For example, daptomycin requires medium supplemented with Ca²⁺, and the lipoglycopeptides dalbavancin and oritavancin require Tween 80 to be added to the growth medium to prevent the depletion of free drug via adsorption to the plastic microplate. In this report, we examine systematically the effects of several different plate types on microdilution broth MIC values for a set of antibiotics against Gram-positive and Gram-negative bacteria, both in medium alone and in medium supplemented with the commonly used additives Tween 80, lysed horse blood, and 50% human serum. We observed very significant differences in measured MICs (up to 100-fold) for some lipophilic antibiotics, such as the Gram-positive lipoglycopeptide dalbavancin and the Gram-negative lipopeptide polymyxins, and found that nonspecific binding plates can replace the need for surfactant additives. Microtiter plate types and any additives should be specified when reporting broth dilution MIC values, as results can vary dramatically for some classes of antibiotics.

Vancomycin-resistant enterococcus infection in the hematopoietic stem cell transplant recipient: an overview of epidemiology, management, and prevention

Vancomycin-resistant enterococcus (VRE) is now one of the leading causes of nosocomial infections in the United States. Hematopoietic stem cell transplantation (HSCT) recipients are at increased risk of VRE colonization and infection. VRE has emerged as a major cause of bacteremia in this population, raising important clinical questions regarding the role and impact of VRE colonization and infection in HSCT outcomes as well as the optimal means of prevention and treatment. We review here the published literature and scientific advances addressing these thorny issues and provide a rational framework for their approach.

Dalbavancin in the treatment of different gram-positive infections: a real-life experience

Dalbavancin is a lipoglycopeptide with a very prolonged half-life enabling treatment with a single intravenous administration that has been approved to treat complicated skin and soft-tissue infections. Information on the efficacy and safety of dalbavancin in other situations is very scarce. This retrospective study included adult patients who received at least one dose of dalbavancin between 2016 and 2017 in 29 institutions in Spain. The primary objective was to report the use of dalbavancin in clinical practice, including its efficacy and tolerability. The potential impact of dalbavancin on reducing the length of hospital stay and hospital costs was also evaluated. A total of 69 patients received dalbavancin during the study period (58.0% male; median age 63.5 years). Dalbavancin was used to treat prosthetic joint infection (29.0%), acute bacterial skin and skin-structure infection (21.7%), osteomyelitis (17.4%) and catheter-related bacteraemia (11.6%). These infections were mainly caused by Staphylococcus aureus (27 isolates), coagulase-negative staphylococci (24 isolates) and Enterococcus spp. (11 isolates). All but two patients received previous antibiotics for a median of 18 days. Dalbavancin was administered for a median of 21 days (range 7-168 days), and concomitant antimicrobial therapy was prescribed to 25 patients (36.2%). The overall clinical success rate of dalbavancin was 84.1%. Adverse events, mainly mild in intensity, were reported in nine patients. Overall, dalbavancin was estimated to reduce hospitalisation by 1160 days, with an estimated overall cost reduction of €211 481 (€3064 per patient). Dalbavancin appears to be an effective therapy for many serious Gram-positive infections.

Natural Products as Platforms To Overcome Antibiotic Resistance

Natural products have served as powerful therapeutics against pathogenic bacteria since the golden age of antibiotics of the mid-20th century. However, the increasing frequency of antibiotic-resistant infections clearly demonstrates that new antibiotics are critical for modern medicine. Because combinatorial approaches have not yielded effective drugs, we propose that the development of new antibiotics around proven natural scaffolds is the best short-term solution to the rising crisis of antibiotic resistance. We analyze herein synthetic approaches aiming to reengineer natural products into potent antibiotics. Furthermore, we discuss approaches in modulating quorum sensing and biofilm formation as a nonlethal method, as well as narrow-spectrum pathogen-specific antibiotics, which are of interest given new insights into the implications of disrupting the microbiome.

Newer glycopeptide antibiotics for treatment of complicated skin and soft tissue infections: systematic review, network meta-analysis and cost analysis

OBJECTIVES

Skin and soft tissue infections (SSTIs) carry significant economic burden, as well as morbidity and mortality, especially when caused by methicillin-resistant Staphylococcus aureus (MRSA). Several new MRSA-active antibiotics have been developed, including semisynthetic glycopeptides (telavancin, dalbavancin and oritavancin). Of these, dalbavancin and oritavancin offer extended dosing intervals.

METHODS

We performed a systematic review, network meta-analysis and cost analysis to compare the newer glycopeptides to standard care and to each other for the treatment of complicated SSTIs (cSSTI). A search for randomized controlled trials (RCTs) was conducted in Medline, Embase and the Cochrane Central Register of Controlled Trials. We also developed a model to evaluate the costs associated with dalbavancin and oritavancin from the third-party payer perspective.

RESULTS

Seven RCTs met the inclusion criteria. Network meta-analyses suggested that the clinical response to telavancin, dalbavancin and oritavancin was similar to standard care (odds ratio (OR) 1.09, 95% confidence interval (CI) 0.90-1.33; OR 0.78, 95% CI 0.52-1.18; and OR 1.06, 95% CI 0.85-1.33, respectively). Head-to-head comparisons showed no difference in clinical response between oritavancin and dalbavancin (OR 1.36; 95% CI 0.85-2.18), oritavancin and telavancin (OR 0.98; 95% CI 0.72-1.31) or dalbavancin and telavancin (OR 0.72; 95% CI 0.45-1.13). Telavancin had a higher incidence of overall adverse events compared to standard care (OR 1.33; 95% CI 1.10-1.61). Compared to telavancin, there were fewer overall adverse events with dalbavancin (OR 0.58; 95% CI 0.45-0.76) and oritavancin (OR 0.71; 95% CI 0.55-0.92). Studies were of high quality overall. Our cost analyses demonstrated that dalbavancin and oritavancin were less costly compared to standard care under baseline assumptions and many scenarios evaluated. The use of dalbavancin could save third-party payers $1442 to $4803 per cSSTI, while the use of oritavancin could save $3571 to $6932 per cSSTI.

CONCLUSIONS

Dalbavancin and oritavancin demonstrate efficacy and safety comparable to standard care in well-designed RCTs and result in cost savings when standard care is treatment that covers MRSA.

Dosing strategies to optimize currently available anti-MRSA treatment options (Part 1: IV options)

INTRODUCTION

Methicillin-resistant Staphylococcus aureus (MRSA) continues to be a predominant pathogen resulting in significant morbidity and mortality. Optimal dosing of anti-MRSA agents is needed to help prevent the development of antimicrobial resistance and to increase the likelihood of a favorable clinical outcome. Areas covered: This review summarizes the available data for antimicrobials routinely used for MRSA infections that are not administered orally or topically. We make recommendations and highlight the current gaps in the literature. A PubMed (1966 - Present) search was performed to identify relevant literature for this review. Expert commentary: Improvements in MIC determination and therapeutic drug monitoring are needed to fully implement individualized dosing that optimizes antimicrobial pharmacodynamics.Additional data will become available for these agents in regards to effectiveness for severe MRSA infections and pharmacokinetic data for special patient populations.

Current and future trends in antibiotic therapy of acute bacterial skin and skin-structure infections

In 2013 the US Food and Drug Administration (FDA) issued recommendations and guidance on developing drugs for treatment of skin infection using a new definition of acute bacterial skin and skin-structure infection (ABSSSI). The new classification includes cellulitis, erysipelas, major skin abscesses and wound infection with a considerable extension of skin involvement, clearly referring to a severe subset of skin infections. The main goal of the FDA was to better identify specific infections where the advantages of a new antibiotic could be precisely estimated through quantifiable parameters, such as improvement of the lesion size and of systemic signs of infection. Before the spread and diffusion of methicillin-resistant Staphylococcus aureus (MRSA) in skin infections, antibiotic therapy was relatively straightforward. Using an empiric approach, a β-lactam was the preferred therapy and cultures from patients were rarely obtained. With the emergence of MRSA in the community setting, initial ABSSSI management has been changed and readdressed. Dalbavancin, oritavancin and tedizolid are new drugs, approved or in development for ABSSSI treatment, that also proved to be efficient against MRSA. Dalbavancin and oritavancin have a long half-life and can be dosed less frequently. This in turn makes it possible to treat patients with ABSSSI in an outpatient setting, avoiding hospitalization or potentially allowing earlier discharge, without compromising efficacy. In conclusion, characteristics of long-acting antibiotics could represent an opportunity for the management of ABSSSI and could profoundly modify the management of these infections by reducing or in some cases eliminating both costs and risks of hospitalization.

Dalbavancin: A New Option for the Treatment of Gram-Positive Infections

Objective:

To review the pharmacology, microbiology, chemistry, in vitro susceptibility, pharmacokinetics, clinical efficacy, safety, tolerability, dosage, and administration of dalbavancin, a new semisynthetic lipoglycopeptide.

Data Sources:

A MEDLINE search, restricted to the English language, was conducted from 1966 through January 2006. Supplementary sources included program abstracts from the Interscience Conference on Antimicrobial Agents and Chemotherapy, American Society of Microbiology, and the Infectious Diseases Society of America from 2000 to 2005 and information available from the manufacturer's Web site.

Study Selection and Data Extraction:

In vitro and preclinical studies, as well as Phase I, II, and III clinical trials, were evaluated to summarize the microbiology, pharmacology, clinical efficacy, and safety of dalbavancin. All published trials and abstracts citing dalbavancin were selected.

Data Synthesis:

Dalbavancin, a novel lipoglycopeptide, has a mechanism of action similar to that of other glycopeptides. It has in vitro activity against a variety of gram-positive organisms, but no activity against gram-negative or vancomycin-resistant enterococci that possess VanA gene. Due to its prolonged half-life (6–10 days), dalbavancin can be administered intravenously once weekly. In Phase II and III clinical trials, dalbavancin was effective and well tolerated for the treatment of skin and soft-tissue infections, catheter-related bloodstream infections, and skin and skin-structure infections. To date, adverse events are mild and limited; the most common include pyrexia, headache, nausea, oral candidiasis, diarrhea, and constipation.

Conclusions:

Dalbavancin appears to be a promising antimicrobial agent for the treatment of gram-positive infections. A new drug application was filed with the Food and Drug Administration (FDA) in December 2004. The FDA issued an approvable letter in 2005 for dalbavancin. If approved, dalbavancin is expected to be launched in the first quarter of 2006.