Efficacy and safety of ceftazidime-avibactam in the treatment of complicated intra-abdominal infections (CIAIs) and complicated urinary tract infections (CUTIs): A meta-analysis of randomized controlled trials

The Surgical Infection Society Guidelines on the Management of Intra-Abdominal Infection: 2024 Update

Background: The Surgical Infection Society (SIS) published evidence-based guidelines for the management of intra-abdominal infection (IAI) in 1992, 2002, 2010, and 2017. Here, we present the most recent guideline update based on a systematic review of current literature. Methods: The writing group, including current and former members of the SIS Therapeutics and Guidelines Committee and other individuals with content or guideline expertise within the SIS, working with a professional librarian, performed a systematic review using PubMed/Medline, the Cochrane Library, Embase, and Web of Science from 2016 until February 2024. Keyword descriptors combined "surgical site infections" or "intra-abdominal infections" in adults limited to randomized controlled trials, systematic reviews, and meta-analyses. Additional relevant publications not in the initial search but identified during literature review were included. The Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) system was utilized to evaluate the evidence. The strength of each recommendation was rated strong (1) or weak (2). The quality of the evidence was rated high (A), moderate (B), or weak (C). The guideline contains new recommendations and updates to recommendations from previous IAI guideline versions. Final recommendations were developed by an iterative process. All writing group members voted to accept or reject each recommendation. Results: This updated evidence-based guideline contains recommendations from the SIS for the treatment of adult patients with IAI. Evidence-based recommendations were developed for antimicrobial agent selection, timing, route of administration, duration, and de-escalation; timing of source control; treatment of specific pathogens; treatment of specific intra-abdominal disease processes; and implementation of hospital-based antimicrobial agent stewardship programs. Summary: This document contains the most up-to-date recommendations from the SIS on the prevention and management of IAI in adult patients.

Adequacy of the Dosing and Infusion Time of Ceftazidime/Avibactam for the Treatment of Gram-Negative Bacterial Infections: A PK/PD Simulation Study

Introduction

Recent studies suggested the potential benefits of extended infusion times to optimize the treatment efficacy of ceftazidime/avibactam, which indicated that the current pharmacokinetic/pharmacodynamic (PK/PD) target may not be sufficient, especially for severe infections. The purpose of this study is to assess the adequacy of dosing strategies and infusion durations of ceftazidime/avibactam when applying higher PK/PD targets.

Methods

This study utilized published PK parameters to conduct Monte Carlo simulations. Different dosages including the recommended regimen based on renal function were simulated and evaluated by the probability of target attainment (PTA) and cumulative fraction of response (CFR). Different PK/PD targets were set for ceftazidime and avibactam. MIC distributions from various sources were used to calculate the CFR.

Results

Multiple PK/PD targets have been set in this study, All recommended dosage could easily achieve the target of 50%fT ≥ MIC (ceftazidime) and 50%fT ≥ CT=1.0 mg/L (avibactam). However, for severe infection patients with normal renal function and augmented renal clearance at the recommended dosage (2000 mg/500 mg, every 8 hours), the infusion duration needs to be extended to 3 hours and 4 hours to achieve the targets of 100%fT ≥ MIC and 100%fT ≥ CT=1.0 mg/L. Only continuous infusion at higher dosages achieved 100%fT ≥ 4×MIC and 100%fT ≥ CT=4.0 mg/L targets to all currently recommended regimens. According to the varying MIC distributions, higher concentrations are needed for Pseudomonas aeruginosa, with the attainment rates vary across different regions.

Conclusion

The current recommended dosing regimen of ceftazidime/avibactam is insufficient for severe infection patients, and continuous infusion is suggested.

Novel β-Lactam/β-Lactamase Inhibitor Combinations versus Alternative Antibiotics in Adults with Hospital-Acquired Pneumonia or Ventilator-Associated Pneumonia: An Integrated Analysis of 3 Randomized Controlled Trials

OBJECTIVES

This study assessed the efficacy and safety of novel β-lactam/β-lactamase inhibitor combinations in adult patients with hospital-acquired pneumonia (HAP) or ventilator-associated pneumonia (VAP).

METHODS

PubMed, Web of Science, the Cochrane Library, Ovid MEDLINE, Embase and EBSCO databases were searched for randomized controlled trials (RCTs) published before September 13, 2020. Only RCTs comparing the treatment efficacy of novel β-lactam/β-lactamase inhibitor combinations with other antibiotics for HAP/VAP in adult patients were included in this integrated analysis.

RESULTS

Three RCTs were included, and no significant difference in clinical cure rate of the test of cure (TOC) was observed between the novel β-lactam/β-lactamase inhibitor combination and comparators (odds ratio [OR], 1.01; 95% CI, 0.81-1.27; I² = 35%). The 28-day all-cause mortality was 16.2% and 17.6% for patients receiving the novel β-lactam/β-lactamase inhibitor combination and those receiving comparators, respectively, and no significant difference was noted (OR, 0.90; 95% CI, 0.69-1.16; I² = 11%). Compared with the comparators, the novel β-lactam/β-lactamase inhibitor combination was associated with a similar microbiological response (OR, 1.06; 95% CI, 0.73-1.54; I² = 64%) and a similar risk of AEs (treatment-emergent AEs [TEAEs]: OR, 1.04; 95% CI, 0.83-1.30; I² = 0%; serious AEs: OR, 1.14; 95% CI, 0.79-1.63; I² = 68%; treatment discontinuation for TEAE: OR, 0.90; 95% CI, 0.62-1.31; I² = 11%).

CONCLUSIONS

The clinical and microbiological responses of novel β-lactam/β-lactamase inhibitor combinations in the treatment of HAP/VAP were similar to those of other available antibiotics. These combinations also shared a similar safety profile to that of comparators.

Dose optimisation based on pharmacokinetic/pharmacodynamic target of tigecycline

Tigecycline, a new first-in-class glycylcycline antibiotic, has shown promising efficacy against a broad range of micro-organisms. It is widely prescribed for various infections, with most prescriptions being considered for off-label use. However, only a few years after its approval by the US Food and Drug Administration (FDA), tigecycline is suspected of increasing all-cause mortality. Some clinicians have suggested such unfavourable outcomes correlate with inadequate drug exposure at the infection site. The pharmacokinetic/pharmacodynamic (PK/PD) profile of a drug plays an important role in predicting its antibiotic effect, which for tigecycline is determined as the ratio of area under the concentration-time curve (AUC) to minimum inhibitory concentration (MIC). In this study, PK/PD targets based on infection sites, bacterial isolates and patient populations are discussed. Generally, a higher dosage of tigecycline for the treatment of serious infections has been recommended in previous reports. However, the latest finding of tigecycline's atypical protein binding property requires consideration when recommending further use. In addition, combination therapy with other antibiotics provides another option by potentially lowering the MICs of multidrug-resistant bacteria.

New β-Lactam-β-Lactamase Inhibitor Combinations

The limited armamentarium against drug-resistant Gram-negative bacilli has led to the development of several novel β-lactam-β-lactamase inhibitor combinations (BLBLIs). In this review, we summarize their spectrum of in vitro activities, mechanisms of resistance, and pharmacokinetic-pharmacodynamic (PK-PD) characteristics. A summary of available clinical data is provided per drug. Four approved BLBLIs are discussed in detail. All are options for treating multidrug-resistant (MDR) Enterobacterales and Pseudomonas aeruginosa Ceftazidime-avibactam is a potential drug for treating Enterobacterales producing extended-spectrum β-lactamase (ESBL), Klebsiella pneumoniae carbapenemase (KPC), AmpC, and some class D β-lactamases (OXA-48) in addition to carbapenem-resistant Pseudomonas aeruginosa Ceftolozane-tazobactam is a treatment option mainly for carbapenem-resistant P. aeruginosa (non-carbapenemase producing), with some activity against ESBL-producing Enterobacterales Meropenem-vaborbactam has emerged as treatment option for Enterobacterales producing ESBL, KPC, or AmpC, with similar activity as meropenem against P. aeruginosa Imipenem-relebactam has documented activity against Enterobacterales producing ESBL, KPC, and AmpC, with the combination having some additional activity against P. aeruginosa relative to imipenem. None of these drugs present in vitro activity against Enterobacterales or P. aeruginosa producing metallo-β-lactamase (MBL) or against carbapenemase-producing Acinetobacter baumannii Clinical data regarding the use of these drugs to treat MDR bacteria are limited and rely mostly on nonrandomized studies. An overview on eight BLBLIs in development is also provided. These drugs provide various levels of in vitro coverage of carbapenem-resistant Enterobacterales, with several drugs presenting in vitro activity against MBLs (cefepime-zidebactam, aztreonam-avibactam, meropenem-nacubactam, and cefepime-taniborbactam). Among these drugs, some also present in vitro activity against carbapenem-resistant P. aeruginosa (cefepime-zidebactam and cefepime-taniborbactam) and A. baumannii (cefepime-zidebactam and sulbactam-durlobactam).

Experience of Ceftazidime/avibactam in a UK tertiary cardiopulmonary specialist center

OBJECTIVES

Antimicrobial resistance is a major threat to public health. New drugs such as Ceftazidime/avibactam have been developed for the treatment of Multi-Drug resistant (MDR) pathogens. Susceptibility can be variable and inappropriate use can add a financial strain on the National Health Service (NHS). There is a pressing need to ensure these new and invaluable antimicrobials are preserved and used effectively.

METHODS

We undertook a retrospective observational study to assess the use of Ceftazidime/avibactam and evaluated prescribing against applied standards.

RESULTS

Between August 2017 and January 2019, 28 patients received 31 courses of Ceftazidime/avibactam. Prescribing according to the approved indications was observed for 68% of prescriptions (p < 0.0001). Duration of therapy was often prolonged but improved with Antimicrobial stewardship interventions. We observed 56% susceptibility (15/27 isolates) of MDR organisms (Pseudomonas, Klebsiella, Burkholderia, Enterobacter aerogenes, Achromobacter). We also report first in vivo experience to treat pulmonary disease caused by Non-tuberculous mycobacteria (NTM). Ceftazidime/avibactam was well tolerated, with no evidence of development of resistance at 6-months follow-up.

CONCLUSIONS

Our study showed that Antimicrobial stewardship interventions led to a more appropriate use of Ceftazidime/avibactam (as measured by duration of therapy), preserving it as a treatment option for MDR infections.

New and promising anti-bacterials: Can this promise be sustained?

The World Health Organization (WHO) announced antimicrobial resistance (AMR) as a major threat to public health which requires that new antimicrobials need to be developed faster than ever before. The rapid development of resistance has rendered many promising antibacterials useless in treating critically ill patients. This article discusses new antibacterials, which got Food and Drug Administration (FDA) approval in the last few years, along with their key pharmacokinetic and pharmacodynamic (PK/PD) advantages, added antimicrobial spectrum, indications, strengths and weaknesses of these drugs from an intensivist point of view. A brief mention has been made on antimicrobial peptides (AMPs), bacteriophages and nanoparticles, which are likely to dominate the future of antibacterials. Finally, it must be understood that the battle against AMR can only be won by a combination of innovative therapies, good infection control practices, strong antibiotic stewardship in the hands of informed healthcare workers.

Non-inferiority versus superiority trial design for new antibiotics in an era of high antimicrobial resistance: the case for post-marketing, adaptive randomised controlled trials

Antimicrobial resistance is one of the most important threats to global health security. A range of Gram-negative bacteria associated with high morbidity and mortality are now resistant to almost all available antibiotics. In this context of urgency to develop novel drugs, new antibiotics for multidrug-resistant Gram-negative bacteria (namely, ceftazidime-avibactam, plazomicin, and meropenem-vaborbactam) have been approved by regulatory authorities based on non-inferiority trials that provided no direct evidence of their efficacy against multidrug-resistant bacteria such as Enterobacteriaceae spp, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Burkholderia cepacia, and Acinetobacter baumannii. The use of non-inferiority and superiority trials, and selection of appropriate and optimal study designs, remains a major challenge in the development, registration, and post-marketing implementation of new antibiotics. Using an example of the development process of ceftazidime-avibactam, we propose a strategy for a new research framework based on adaptive randomised clinical trials. The operational research strategy has the aim of assessing the efficacy of new antibiotics in special groups of patients, such as those infected with multidrug-resistant bacteria, who were not included in earlier phase studies, and for whom it is important to establish an appropriate standard of care.

Evaluation of the efficacy and safety of ceftazidime/avibactam in the treatment of Gram-negative bacterial infections: a systematic review and meta-analysis

Data on the efficacy and safety of ceftazidime/avibactam (CAZ-AVI) are limited. A systematic review and meta-analysis was conducted to clarify the role of CAZ-AVI for patients with serious Gram-negative bacterial infections. The PubMed, EMBASE and Cochrane Library databases were searched for randomised controlled trials (RCTs) and cohort studies involving CAZ-AVI. Summary risk ratios (RRs) and 95% confidence intervals (CIs) were calculated using a fixed- or random-effects model. Twelve articles (4951 patients) were included, consisting of nine RCTs and three observational studies comparing CAZ-AVI with other regimens, e.g. carbapenems or colistin. CAZ-AVI showed a comparable clinical response (RR = 0.99, 95% CI 0.96-1.02; I2 = 0%) and non-inferior bacterial eradication (RR = 1.04, 95% CI 0.93-1.17; I2 = 79.1%) to carbapenems. No significant difference was detected between groups regarding mortality and adverse events. Moreover, subgroup analyses demonstrated that CAZ-AVI improved the clinical response (RR = 1.61, 95% CI 1.13-2.29) with reduced mortality (RR = 0.29, 95% CI 0.13-0.63) in patients infected by carbapenem-resistant Enterobacteriaceae versus comparators. Likewise, CAZ-AVI improved the clinical cure rate of bloodstream infections (RR = 2.11, 95% CI 1.54-2.88). An improved ability of CAZ-AVI in microbiological eradication was also detected in patients with complicated urinary tract infections (RR = 1.13, 95% CI 1.05-1.21). CAZ-AVI exhibited comparable efficacy and safety with carbapenems. Therefore, this agent might be a potential powerful agent for patients with serious Gram-negative bacterial infections.