Clinical efficacy and safety of cefiderocol in the treatment of acute bacterial infections: A systematic review and meta-analysis of randomised controlled trials

Systematic Review and Meta-Analysis of Clinical Efficacy and Safety of Meropenem-Vaborbactam versus Best-Available Therapy in Patients with Carbapenem-Resistant Enterobacteriaceae Infections

Antimicrobial resistance is increasingly concerning, causing millions of deaths and a high cost burden. Given that carbapenemase-producing Enterobacterales are particularly concerning due to their ability to develop structural modifications and produce antibiotic-degrading enzymes, leading to high resistance levels, we sought to summarize the available data on the efficacy and safety regarding the combination of meropenem-vaborbactam (MV) versus the best available therapy (BAT). Articles related to our objective were searched in the PubMed and Scopus databases inception to July 2024. To assess the quality of the studies, we used the Cochrane risk-of-bias tool, RoB2. The outcomes were pooled as a risk ratio (RR) and a 95% confidence interval (95%CI). A total of four published studies were involved: one retrospective cohort study and three phase 3 trials, including 432 patients treated with MV and 426 patients treated with BAT (mono/combination therapy with polymyxins, carbapenems, aminoglycosides, colistin, and tigecycline; or ceftazidime-avibactam; or piperacillin-tazobactam). No significant difference in the clinical response rate was observed between MV and the comparators at the TOC (RR = 1.29, 95%CI [0.92, 1.80], p = 0.14) and EOT (RR = 1.66, 95%CI [0.58, 4.76], p = 0.34) visits. MV was associated with a similar microbiological response as the comparators at TOC (RR = 1.63, 95%CI [0.85, 3.11], p = 0.14) and EOT assessment (RR = 1.16, 95%CI [0.88, 1.54], p = 0.14). In the pooled analysis of the four studies, 28-day all-cause mortality was lower for MV than the control groups (RR = 0.47, 95%CI [0.24, 0.92], p = 0.03). MV was associated with a similar risk of adverse events (AEs) as comparators (RR = 0.79, 95%CI [0.53, 1.17], p = 0.23). Additionally, MV was associated with fewer renal-related AEs than the comparators (RR = 0.32, 95%CI [0.15, 0.66], p = 0.002). MV was associated with a similar risk of treatment discontinuation due to AEs (RR = 0.76, 95%CI [0.38, 1.49], p = 0.42) or drug-related AEs (RR = 0.56, 95%CI [0.28, 1.10], p = 0.09) as the comparators. In conclusion, MV presents a promising therapeutic option for treating CRE infections, demonstrating similar clinical and microbiological responses as other comparators, with potential advantages in mortality outcomes and renal-related AEs.

Size and charge effects of metal nanoclusters on antibacterial mechanisms

Nanomaterials, specifically metal nanoclusters (NCs), are gaining attention as a promising class of antibacterial agents. Metal NCs exhibit antibacterial properties due to their ultrasmall size, extensive surface area, and well-controlled surface ligands. The antibacterial mechanisms of metal NCs are influenced by two primary factors: size and surface charge. In this review, we summarize the impacts of size and surface charge of metal NCs on the antibacterial mechanisms, their interactions with bacteria, and the factors that influence their antibacterial effects against both gram-negative and gram-positive bacteria. Additionally, we highlight the mechanisms that occur when NCs are negatively or positively charged, and provide examples of their applications as antibacterial agents. A better understanding of relationships between antibacterial activity and the properties of metal NCs will aid in the design and synthesis of nanomaterials for the development of effective antibacterial agents against bacterial infections. Based on the remarkable achievements in the design of metal NCs, this review also presents conclusions on current challenges and future perspectives of metal NCs for both fundamental investigations and practical antibacterial applications.

Outcome of patients with carbapenem-resistant Acinetobacter baumannii infections treated with cefiderocol: A multicenter observational study

BACKGROUND

No clear evidence supports the use of cefiderocol as first line treatment in A. baumannii infections.

METHODS

We conducted an observational retrospective/prospective multicenter study including all patients> 18 years with carbapenem-resistant A. baumannii (CRAB) infections treated with cefiderocol, from June 12021 to October 30 2022. Primary endpoint was 30-day mortality, secondary end-points the clinical and microbiological response at 7 days and at the end of treatment. Furthermore, we compared the clinical and microbiological outcomes among patients who received cefiderocol in monotherapy or in combination.

RESULTS

Thirty-eight patients with forty episodes of infection were included [mean age 65 years (SD+16.3), 75% males, 90% with hospital-acquired infections and 70% showing sepsis or septic shock]. The most common infections included unknown source or catheter-related bacteremia (45%) and pneumonia (40%). We observed at 7 days and at the end of therapy a rate of microbiological failure of 20% and 10%, respectively, and of clinical failure of 47.5% and 32.5%, respectively; the 30-day mortality rate was 47.5%. At multivariate analysis clinical failure at 7 days of treatment was the only independent predictor of 30-day mortality. Comparing monotherapy (used in 72.5%) vs. combination therapy (used in 27.5%), no differences were observed in mortality (51.7 vs 45.5%) and clinical (41.4 vs 63.7%) or microbiological failure (24.1 vs 9.1%).

CONCLUSIONS

The findings of this study reinforce the effectiveness of cefiderocol in CRAB infections, also as monotherapy. However, prospective multicenter studies with larger sample sizes and a control group treated with standard of care are needed to identify the best treatment for CRAB infections.

Empiric treatment of patients with sepsis and septic shock and place in therapy of cefiderocol: a systematic review and expert opinion statement

Carbapenem-resistant Gram-negative bacteria are frequent causes of sepsis and septic shock in intensive care unit (ICU) and thus considered a public health threat. Until now, the best available therapies consist of combinations of preexisting or new antibiotics with β-lactamase inhibitors (either new or preexisting). Several mechanisms of resistance, especially those mediated by metallo-β-lactamases (MBL), are responsible for the inefficacy of these treatments, leaving an unmet medical need. Intravenous cefiderocol has been recently approved by the American Food and Drug Administration (FDA) and European Medicines Agency (EMA) for the treatment of complicated urinary tract infections and nosocomial pneumonia due to Gram-negative, when limited therapeutical options are available. In addition, its ability to hijack bacterial iron uptake mechanisms makes cefiderocol stable against the whole Ambler β-lactamase inhibitors and increases the in vitro efficacy against Gram-negative pathogens (e.g., Enterobacterales spp., Pseudomonas aeruginosa, and Acinetobacter baumannii). Trials have already demonstrated their non-inferiority to comparators. In 2021, ESCMID guidelines released a conditional recommendation supporting the use of cefiderocol against metallo-β-lactamase-producing Enterobacterales and against Acinetobacter baumannii. This review provides the opinion of experts about the general management of empiric treatment of patients with sepsis and septic shock in the intensive care unit and detects the proper place in therapy of cefiderocol considering recent evidence sought through a systematic search.

Cefiderocol for the Treatment of Multidrug-Resistant Gram-Negative Bacteria: A Systematic Review of Currently Available Evidence

Cefiderocol is a novel synthetic siderophore-conjugated antibiotic that hijacks the bacterial iron transport systems facilitating drug entry into cells, achieving high periplasmic concentrations. This systematic review analyzed the currently available literature on cefiderocol. It summarized in vitro susceptibility data, in vivo antimicrobial activity, pharmacokinetics/pharmacodynamics (PK/PD), clinical efficacy, safety and resistance mechanisms of cefiderocol. Cefiderocol has potent in vitro and in vivo activity against multidrug-resistant (MDR) Gram-negative bacteria, including carbapenem-resistant isolates. But New Delhi Metallo-β-lactamase (NDM)- positive isolates showed significantly higher MICs than other carbapenemase-producing Enterobacterales, with a susceptible rate of 83.4% for cefiderocol. Cefiderocol is well-tolerated, and the PK/PD target values can be achieved using a standard dose regimen or adjusted doses according to renal function. Clinical trials demonstrated that cefiderocol was non-inferiority to the comparator drugs in treating complicated urinary tract infection and nosocomial pneumonia. Case reports and series showed that cefiderocol was a promising therapeutic agent in carbapenem-resistant infections. However, resistant isolates and reduced susceptibility during treatment to cefiderocol have already been reported. In conclusion, cefiderocol is a promising powerful weapon for treating MDR recalcitrant infections.

All-cause mortality rates in adults with carbapenem-resistant Gram-negative bacterial infections: a comprehensive review of pathogen-focused, prospective, randomized, interventional clinical studies

INTRODUCTION

Pathogen-focused, randomized, controlled trials (PF-RCT) are important in the fight against carbapenem-resistant (CR) Gram-negative infections. Some recently approved antibiotics and older generic antibiotics with activity against CR Gram-negative bacteria were investigated in PF-RCTs in a variety of infections.

AREAS COVERED

We searched Pubmed, Cochrane database and international clinical trial databases for PF-RCTs for the period between 2005 and 2020 and compared the study designs, patient populations, infection types, pathogens, and Day-28 all-cause mortality (ACM).

EXPERT OPINION

PF-RCTs are particularly challenging to quantitatively assess and compare due to the heterogeneity in infection types, pathogens, CR mechanism, inclusion/exclusion criteria, and endpoints. Data interpretation is further complicated by lack of formal statistical analysis plans and/or non-inferiority design, and limited power across most PF-RCTs. The studies with new antibiotics (i.e. plazomicin, meropenem/vaborbactam, cefiderocol) ranked lower regarding feasibility, with relatively small sample sizes (analyzed: 37-118) versus the comparative effectiveness studies of older generic drugs (analyzed: 94-406). ACM ranged between 11.8% and 40% for CR Enterobacterales, 17.7% and 57.4% for CR Acinetobacter spp., and 20.0% and 30.8% for CR Pseudomonas aeruginosa. The information gathered must be considered carefully alongside the study limitations and caution should be exercised when making direct comparisons across trials.

Safety evaluation of current therapies for high-risk severely ill patients with carbapenem-resistant infections

INTRODUCTION

Infections due to carbapenem-resistant Gram-negative bacteria (CR-GNB) are increasingly frequent events, which are associated with a high mortality rate. Traditionally, combination regimens including high doses of "old antibiotics" such as polymyxins, tigecycline, and aminoglycosides have been used to treat these infections, but they were often associated with low efficacy and high excess of side effects and toxicity, especially nephrotoxicity. Along with the development of new compounds, the last decade has seen substantial improvements in the management of CR infections.

AREAS COVERED

In this review, we aimed to discuss the safety characteristics and tolerability of different new options for treatment of CR infections.

EXPERT OPINION

The availability of new drugs showing a potent in vitro activity against CR-GNB represents a unique opportunity to face the threat of resistance, while potentially reducing toxicity. A thorough understanding of the safety profile from clinical trials may guide the use of these new drugs in critically ill patients at high risk for the development of adverse events. Future data coming from real-life studies for drugs targeting CR infections are crucial to confirm the safety profile observed in pivotal trials.

Treatment of UTIs Due to Klebsiella pneumoniae Carbapenemase-Producers: How to Use New Antibiotic Drugs? A Narrative Review

Background: K. pneumoniae is one of the bacteria most frequently causing health care-associated urinary tract infections, and increasingly incriminating Klebsiella pneumoniae carbapenemase producers (KPCp). Most infections caused by KPCp are nosocomial and might cause serious issues, even leading to death in half of the reported cases. Our aim was to identify the best strategy, based on available scientific data, for the use of new antibiotic treatments to manage KPCp UTIs. Methods: this narrative review of the literature was performed according to the criteria of preferred reporting items for systematic review and meta-analyses statement (PRISMA) (2020). Results and Conclusions: KPCp-UTIs are a real challenge for physicians. While cefiderocol, meropenem-vaborbactam, ceftazidim-avibactam, and imipenem-relebactam represent a major step forward in the treatment of these UTIs, no guidelines are currently available, in view of choosing the most appropriate treatment, in each specific case.