1316. Pharmacokinetic/Pharmacodynamic Analyses of Cefiderocol in Critically Ill Patients

Treatment of critically ill patients with cefiderocol for infections caused by multidrug-resistant pathogens: review of the evidence

Appropriate antibiotic treatment for critically ill patients with serious Gram-negative infections in the intensive care unit is crucial to minimize morbidity and mortality. Several new antibiotics have shown in vitro activity against carbapenem-resistant Enterobacterales (CRE) and difficult-to-treat resistant Pseudomonas aeruginosa. Cefiderocol is the first approved siderophore beta-lactam antibiotic with potent activity against multidrug-resistant, carbapenem-resistant, difficult-to-treat or extensively drug-resistant Gram-negative pathogens, which have limited treatment options. The spectrum of activity of cefiderocol includes drug-resistant strains of Acinetobacter baumannii, P. aeruginosa, Stenotrophomonas maltophilia, Achromobacter spp. and Burkholderia spp. and CRE that produce serine- and/or metallo-carbapenemases. Phase 1 studies established that cefiderocol achieves adequate concentration in the epithelial lining fluid in the lung and requires dosing adjustment for renal function, including patients with augmented renal clearance and continuous renal-replacement therapy (CRRT); no clinically significant drug-drug interactions are expected. The non-inferiority of cefiderocol versus high-dose, extended-infusion meropenem in all-cause mortality (ACM) rates at day 14 was demonstrated in the randomized, double-blind APEKS-NP Phase 3 clinical study in patients with nosocomial pneumonia caused by suspected or confirmed Gram-negative bacteria. Furthermore, the efficacy of cefiderocol was investigated in the randomized, open-label, pathogen-focused, descriptive CREDIBLE-CR Phase 3 clinical study in its target patient population with serious carbapenem-resistant Gram-negative infections, including hospitalized patients with nosocomial pneumonia, bloodstream infection/sepsis, or complicated urinary tract infections. However, a numerically greater ACM rate with cefiderocol compared with BAT led to the inclusion of a warning in US and European prescribing information. Cefiderocol susceptibility results obtained with commercial tests should be carefully evaluated due to current issues regarding their accuracy and reliability. Since its approval, real-world evidence in patients with multidrug-resistant and carbapenem-resistant Gram-negative bacterial infections suggests that cefiderocol can be efficacious in certain critically ill patient groups, such as those requiring mechanical ventilation for COVID-19 pneumonia with subsequently acquired Gram-negative bacterial superinfection, and patients with CRRT and/or extracorporeal membrane oxygenation. In this article, we review the microbiological spectrum, pharmacokinetics/pharmacodynamics, efficacy and safety profiles and real-world evidence for cefiderocol, and look at future considerations for its role in the treatment of critically ill patients with challenging Gram-negative bacterial infections.

[Clinical experience using cefiderocol]

BACKGROUND

Infections due to antibiotic-resistant bacteria are threatening modern healthcare, and antibacterial resistance has become one of the greatest threats to public health. In Germany 54,500 patients become infected with antibiotic-resistant bacteria per year, causing about 2400 attributable deaths. Rising resistance in Gram-negative bacteria especially carbapenem-resistant pathogens is of particular concern due to the lack of effective and safe alternative treatment options.

OBJECTIVE

The results from trials and compassionate-use programs with the new antibiotic cefiderocol, which was approved by the European Medicines Agency (EMA) in April 2020 for the treatment of adults with infections caused by aerobic Gram-negative bacteria, are summarized.

RESULTS

The new β‑lactam antibiotic cefiderocol is the first siderophore cephalosporin indicated for the treatment of infections due to aerobic Gram-negative organisms in adults with limited treatment options. Its chemical structure and its unique mechanism of action confer enhanced stability against β‑lactamases including all classes of clinically relevant carbapenemases. In vitro data show high antibacterial activity against multidrug resistant Gram-negative bacteria, Enterobacterales and nonfermenters, including carbapenem-resistant strains. In clinical trials, cefiderocol showed superiority in complicated urinary tract infection in comparison to imipenem and non-inferiority versus meropenem in hospital-acquired/ventilator-associated pneumonia patients and severe infections caused by carbapenem-resistant pathogens.

CONCLUSION

Clinical trial data and case reports identified in the literature search show that cefiderocol is a promising treatment option for severe infections caused by drug-resistant Gram-negative bacteria, particularly carbapenem-resistant bacteria.

Pharmacokinetic evaluation of cefiderocol for the treatment of multidrug resistant Gram-negative infections

INTRODUCTION

Cefiderocol is a siderophore cephalosporin antibiotic and first of its kind approved by the Food and Drug Administration for the treatment of complicated urinary tract infections (cUTI) and hospital-acquired and ventilator-associated bacterial pneumonia (HABP/VABP) in patients 18 years or older caused by susceptible organisms. Cefiderocol's unique mechanism of iron chelation improves Gram-negative membrane penetration as the bacteria's iron uptake mechanism recognizes the chelated iron antibiotic and iron for entry. This also allows for the evasion of cefiderocol from cell entry-related resistance mechanisms.

AREAS COVERED

This review covers the mechanism of action, resistance mechanisms, pharmacokinetics in various patient populations, and pharmacodynamics. Relevant literature evaluating efficacy and safety are discussed.

EXPERT OPINION

Limited treatment options are available for the treatment of carbapenem-resistantorganisms. Clinical trials have demonstrated that cefiderocol is no worse than alternative treatment options for cUTIs and HABP/VABP, but more data are currently available to support the use of beta-lactam beta-lactamase inhibitor agents, where susceptible. Mortality differences demonstrated in patients with pneumonia and bloodstream infections must further be explored and logistical and practical considerations regarding susceptibility testing and use as monotherapy vs. combination therapy must be considered prior to confidently recommending cefiderocol for regular use in systemic infections.

Pharmacological and clinical profile of cefiderocol, a siderophore cephalosporin against gram-negative pathogens

Introduction: Increasing resistance of gram-negative bacteria poses a serious threat to global health. Thus, efficacious and safe antibiotics against resistant pathogens are urgently needed. Cefiderocol, a siderophore cephalosporin, addresses this unmet need.Areas covered: For this article, we screened all preclinical and clinical studies on cefiderocol published by January 2021 on PubMed. Also, regulatory documents, recent conference contributions, and selected data of antibiotic competitors are reviewed. We provide a comprehensive overview of the mode of action, in vitro and in vivo activity, pharmacokinetics/pharmacodynamics, and human pharmacokinetics. Last, we discuss the efficacy and safety data from the pivotal trials.Expert opinion: Cefiderocol was in vitro potent against virtually all gram-negative pathogens and resistance was rare. The target site pharmacokinetics (i.e. urinary and lung penetration) have been well described in humans and important PK/PD targets were reached. In the clinical trials, cefiderocol was non-inferior to carbapenems in the treatment of complicated urinary tract infections and nosocomial pneumonia. Against carbapenem-resistant gram-negative pathogens, cefiderocol was similar to the best available therapy, which was mainly based on the backbone agent colistin. Overall, a substantial body of evidence supports the clinical use of cefiderocol in patients with gram-negative infections and limited treatment options.

Cefiderocol in Critically Ill Patients with Multi-Drug Resistant Pathogens: Real-Life Data on Pharmacokinetics and Microbiological Surveillance

Cefiderocol is a new siderophore-cephalosporin for the treatment of multi-drug resistant Gram-negative pathogens. As a reserve agent, it will and should be used primarily in critically ill patients in the upcoming years. Due to the novelty of the substance little data on the pharmacokinetics in critically ill patients with septic shock and renal failure (including continuous renal replacement therapy and cytokine adsorber therapy) is available. We performed therapeutic drug monitoring in a cohort of five patients treated with cefiderocol, to improve the knowledge on pharmacokinetics in this vulnerable patient population. As expected for a cephalosporin with predominantly renal elimination the maintenance dose could be reduced in patients with renal impairment or on continuous renal replacement therapy. The manufacturer’s dosing instructions were sufficient to achieve a drug level well above the MIC. However, the addition of a cytokine adsorber might reduce serum levels substantially, so that in this context therapeutic drug monitoring and dose adjustment are recommended.