1298. Population Pharmacokinetics of Ceftazidime-avibactam among Critically-ill Patients with and without Receipt of Continuous Renal Replacement Therapy

A descriptive pharmacokinetic/pharmacodynamic analysis of continuous infusion ceftazidime-avibactam for treating DTR gram-negative infections in a case series of critically ill patients undergoing continuous veno-venous haemodiafiltration (CVVHDF)

PURPOSE

To explore pharmacokinetic/pharmacodynamic (PK/PD) profile of continuous infusion (CI) ceftazidime-avibactam for treating difficult-to-treat resistant Gram-negative (DTR-GN) infections in critical patients undergoing continuous venovenous haemodiafiltration (CVVHDF).

MATERIALS AND METHODS

Patients treated with CI ceftazidime-avibactam for DTR-GN infections during CVVHDF were retrospectively assessed. Ceftazidime and avibactam concentrations were measured at steady-state and the free fraction (fC_ss) was calculated. Total clearance (CL_tot) of both agents were calculated and the impact of CVVHDF intensity was assessed by linear regression. The joint PK/PD target of ceftazidime-avibactam was defined as optimal when both fC_ss/MIC≥4 for ceftazidime and fC_ss/C_T > 1 for avibactam were achieved. Relationship between ceftazidime-avibactam PK/PD targets and microbiological outcome was assessed.

RESULTS

Eight patients with DTR-GN infections were retrieved. Median fC_ss were 84.5 (73.7-87.7 mg/L) for ceftazidime and 24.8 mg/L (20.7-25.8 mg/L) for avibactam. Median CL_tot was 2.39 L/h (2.05-2.96 L/h) for ceftazidime and 2.56 L/h (2.12-2.98 L/h) for avibactam. Median CVVHDF dose was 38.6 mL/h/kg (35.9-40.0 mL/kg/h). CL_tot were linearly correlated with CVVHDF dose (r = 0.53;p = 0.03, and r = 0.64;p = 0.006, respectively). The joint PK/PD targets were optimal granting microbiological eradication in all the assessable cases.

CONCLUSION

CI administration of 1.25-2.5 g q8h ceftazidime-avibactam may allow prompt attainment and maintenance of optimal joint PK/PD targets during high-intensity CVVHDF.

Jumping into the future: overcoming pharmacokinetic/pharmacodynamic hurdles to optimize the treatment of severe difficult to treat-Gram-negative infections with novel beta-lactams

INTRODUCTION

The choice of best therapeutic strategy for difficult-to-treat resistance (DTR) Gram-negative infections currently represents an unmet clinical need.

AREAS COVERED

This review provides a critical reappraisal of real-world evidence supporting the role of pharmacokinetic/pharmacodynamic (PK/PD) optimization of novel beta-lactams in the management of DTR Gram-negative infections. The aim was to focus on prolonged and/or continuous infusion administration, penetration rates into deep-seated infections, and maximization of PK/PD targets in special renal patient populations. Retrieved findings were applied to the three most critical clinical scenarios of Gram-negative resistance phenotypes (i.e. carbapenem-resistant Enterobacterales; difficult-to-treat resistant Pseudomonas aeruginosa, and carbapenem-resistant Acinetobacter baumannii).

EXPERT OPINION

Several studies supported the role of PK/PD optimization of beta-lactams in the management of DTR Gram-negative infections for both maximizing clinical efficacy and preventing resistance emergence. Optimizing antimicrobial therapy with novel beta-lactams based on the so called 'antimicrobial therapy puzzle' PK/PD concepts may represent a definitive jump into the future toward a personalized patient management of DTR Gram negative infections. Establishing a dedicated and coordinated multidisciplinary team and implementing a real-time TDM-guided personalized antimicrobial exposure optimization of novel beta-lactams based on expert clinical pharmacological interpretation, could represent crucial cornerstones for the proper management of DTR Gram-negative infections.

Pharmacokinetics, Pharmacodynamics, and Dosing Considerations of Novel β-Lactams and β-Lactam/β-Lactamase Inhibitors in Critically Ill Adult Patients: Focus on Obesity, Augmented Renal Clearance, Renal Replacement Therapies, and Extracorporeal Membrane Oxygenation

OBJECTIVE

Dose optimization of novel β-lactam antibiotics (NBLA) has become necessary given the increased prevalence of multidrug-resistant infections in intensive care units coupled with the limited number of available treatment options. Unfortunately, recommended dose regimens of NBLA based on PK/PD indices are not well-defined for critically ill patients presenting with special situations (i.e., obesity, extracorporeal membrane oxygenation (ECMO), augmented renal clearance (ARC), and renal replacement therapies (RRT)). This review aimed to discuss and summarize the available literature on the PK/PD attained indices of NBLA among critically ill patients with special circumstances.

DATA SOURCES

PubMed, MEDLINE, Scopus, Google Scholar, and Embase databases were searched for studies published between January 2011 and May 2022.

STUDY SELECTION AND DATA EXTRACTION

Articles relevant to NBLA (i.e., ceftolozane/tazobactam, ceftazidime/avibactam, cefiderocol, ceftobiprole, imipenem/relebactam, and meropenem/vaborbactam) were selected. The MeSH terms of "obesity", "augmented renal clearance", "renal replacement therapy", "extracorporeal membrane oxygenation", "pharmacokinetic", "pharmacodynamic" "critically ill", and "intensive care" were used for identification of articles. The search was limited to adult humans' studies that were published in English. A narrative synthesis of included studies was then conducted accordingly.

DATA SYNTHESIS

Available evidence surrounding the use of NBLA among critically ill patients presenting with special situations was limited by the small sample size of the included studies coupled with high heterogeneity. The PK/PD target attainments of NBLA were reported to be minimally affected by obesity and/or ECMO, whereas the effect of renal functionality (in the form of either ARC or RRT) was more substantial.

CONCLUSION

Critically ill patients presenting with special circumstances might be at risk of altered NBLA pharmacokinetics, particularly in the settings of ARC and RRT. More robust, well-designed trials are still required to define effective dose regimens able to attain therapeutic PK/PD indices of NBLA when utilized in those special scenarios, and thus aid in improving the patients' outcomes.

Ceftazidime-Avibactam for the Treatment of Serious Gram-Negative Infections with Limited Treatment Options: A Systematic Literature Review

INTRODUCTION

A systematic literature review was undertaken to evaluate real-world use of ceftazidime-avibactam for infections due to aerobic Gram-negative organisms in adults with limited treatment options.

METHODS

Literature searches retrieved peer-reviewed publications and abstracts from major international infectious disease congresses from January 2015 to February 2021. Results were screened using pre-defined criteria to limit the dataset to relevant publications (notable exclusions were paediatric data and outcomes data for bacteria intrinsically resistant to ceftazidime-avibactam). Data for included publications were subjected to qualitative synthesis.

RESULTS

Seventy-three relevant publications (62 peer-reviewed articles; 10 abstracts) comprising 1926 patients treated with ceftazidime-avibactam (either alone or combined with other antimicrobials) and 1114 comparator/control patients were identified. All patients were hospitalised for serious illness and most had multiple comorbidities. The most common infections were pneumonia, bacteraemia, and skin/soft tissue, urinary tract, or abdominal infections; smaller numbers of patients with meningitis, febrile neutropenia, osteomyelitis, and cystic fibrosis were also included. Carbapenem-resistant or carbapenemase-producing Enterobacterales (CRE; n = 1718) and carbapenem-resistant, multidrug-resistant (MDR), and extensively drug-resistant Pseudomonas aeruginosa (n = 150) were the most common pathogens. Most publications reported positive outcomes for ceftazidime-avibactam treatment (clinical success rates ranged from 45 to 100% and reported 30-day mortality from 0 to 63%), which were statistically superior versus comparators in some studies. ceftazidime-avibactam resistance emergence occurred infrequently and mostly in Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae strains.

CONCLUSION

This review provides qualitative evidence of successful use of ceftazidime-avibactam for the treatment of hospitalised patients with CRE and MDR P. aeruginosa infections with limited treatment options.