Focus on ceftazidime-avibactam for optimizing outcomes in complicated intra-abdominal and urinary tract infections

Clinical characteristics and outcomes of patients with multidrug-resistant Gram-negative bacterial infections treated with ceftazidime/avibactam

OBJECTIVES

The aim of this study was to investigate the clinical characteristics and outcomes of patients with infections caused by multidrug-resistant Gram-negative bacteria (MDR-GNB) treated with ceftazidime/avibactam (CAZ/AVI) during the period September 2019 to June 2020 since CAZ/AVI had been marketed in China.

METHODS

A total of 20 MDR-GNB-infected patients were retrospectively identified using the electronic medical record system in West China Hospital.

RESULTS

The mean age of the 20 patients was 54.5 ± 17.37 years and 14 (70%) were male. Pneumonia (n = 12; 60%), complicated intra-abdominal infection (n = 10; 50%), and bloodstream infection (n = 7; 35%) were the most common infection sources. Klebsiella pneumoniae (55% 18/33) was the predominant pathogen. The 14-day clinical cure rate was 45%. The 14-day and 30-day mortality rates were 25% and 55%, respectively. No significant difference was found in 30-day mortality between treatment with CAZ/AVI monotherapy and combination regimens (P > 0.05). Three patients suffered from adverse drug reactions such as diarrhoea.

CONCLUSION

No significant difference was found between the effectiveness of CAZ/AVI in the clinical failure and cure groups as salvage treatment of MDR-GNB infection.

Cost-effectiveness analysis comparing ceftazidime/avibactam (CAZ-AVI) as empirical treatment comparing to ceftolozane/tazobactam and to meropenem for complicated intra-abdominal infection (cIAI)

Background

The rising incidence of resistance to currently available antibiotics among pathogens, particularly Gram-negative pathogens, in complicated intra-abdominal infections (cIAIs) has become a challenge for clinicians. Ceftazidime/avibactam (CAZ-AVI) is a fixed-dose antibiotic approved in Europe and the United States for treating (in combination with metronidazole) cIAI in adult hospitalised patients who have limited or no alternative treatment options. The approval was based on the results of RECLAIM, a Phase III, parallel-group, comparative study (RECLAIM 1 [NCT01499290] and RECLAIM 2 [NCT01500239]). The objective of our study was to assess the cost-effectiveness of CAZ-AVI plus metronidazole compared with 1) ceftolozane/tazobactam plus metronidazole and 2) meropenem, as an empiric treatment for the management of cIAI in Italy.

Methods

A sequential, patient-level simulation model, with a 5-year time horizon and 3% annual discount rate (applied to both costs and health benefits), was developed using Microsoft Excel® to demonstrate the clinical course of the disease. The impact of resistant pathogens was included as an additional factor.

Results

In the base-case analysis, the CAZ-AVI sequence (CAZ-AVI plus metronidazole followed by a colistin + tigecycline + high-dose meropenem combination after treatment failure), when compared to sequences for ceftolozane/tazobactam (ceftolozane/tazobactam plus metronidazole followed by colistin + tigecycline + high-dose meropenem after treatment failure) and meropenem (meropenem followed by colistin + tigecycline + high-dose meropenem after treatment failure), had better clinical outcomes with higher cure rates (93.04% vs. 91.52%; 92.98% vs. 90.24%, respectively), shorter hospital stays (∆ = − 0.38 and ∆ = − 1.24 days per patient, respectively), and higher quality-adjusted life years (QALYs) gained per patient (4.021 vs. 3.982; 4.019 vs. 3.960, respectively). The incremental cost effectiveness ratio in the CAZ-AVI sequence was €4099 and €15,574 per QALY gained versus each comparator sequence, respectively, well below the willingness-to-pay threshold of €30,000 per QALY accepted in Italy.

Conclusions

The model results demonstrated that CAZ-AVI plus metronidazole could be a cost-effective alternative when compared with other antibiotic treatment options, as it is expected to provide better clinical benefits in hospitalised patients with cIAI in Italy.

Cure of recurring Klebsiella pneumoniae carbapenemase-producing Klebsiella pneumoniae septic shock episodes due to complicated soft tissue infection using a ceftazidime and avibactam-based regimen: a case report

Background

Infections caused by multidrug-resistant Enterobacteriaceae are hard to treat and life-threatening due to reduced therapeutic options. Systemic infections caused by Klebsiella pneumoniae carbapenemase-producing Klebsiella pneumoniae strains have increased in many European regions, becoming frequent in many clinical settings, and are associated with high mortality. The co-formulation of ceftazidime, a third-generation cephalosporin, with avibactam, a new suicide inhibitor beta-lactamase inhibitor able to block most Klebsiella pneumoniae carbapenemases, has been recently licensed, with promising results in patients with limited or absent therapeutic options. Little is known, however, as to the efficacy of such a combination in patients with soft tissue infections caused by multidrug-resistant Klebsiella pneumoniae carbapenemase-producing strains of Klebsiella pneumoniae.

Case presentation

A Caucasian 53-year-old man with paraplegia suffered multiple vertebral fractures due to a car crash. He was treated with external fixators that became infected early after insertion and were repeatedly and inefficiently treated with multiple antibiotics. He suffered repeated septic episodes caused by Klebsiella pneumoniae carbapenemase-producing Klebsiella pneumoniae strains with a multidrug-resistant profile. Meropenem, tigecycline, and colistin combinations allowed only temporary improvements, but septic shock episodes recurred, in spite of removal of infected external fixators. After approval of pre-marketing prescription by our local Ethics Committee, full clinical resolution was obtained with a compassionate treatment using meropenem and ceftazidime/avibactam in combination for 16 days.

Conclusions

Our experience provides additional evidence that ceftazidime/avibactam, possibly in combination with meropenem rescued by avibactam, may be an efficacious treatment option also for complicated skin and soft tissue infections caused by multidrug-resistant strains of Klebsiella pneumoniae carbapenemase-producing Klebsiella pneumoniae.

Avibactam Pharmacokinetic/Pharmacodynamic Targets

Avibactam is a novel non-β-lactam β-lactamase inhibitor that has been approved in the United States and Europe for use in combination with ceftazidime. Combinations of avibactam with aztreonam or ceftaroline fosamil have also been clinically evaluated. Until recently, there has been very little precedence of which pharmacokinetic/pharmacodynamic (PK/PD) indices and magnitudes are appropriate to use for β-lactamase inhibitors in population PK modeling for analyzing potential doses and susceptibility breakpoints. For avibactam, several preclinical studies using different in vitro and in vivo models have been conducted to identify the PK/PD index of avibactam and the magnitude of exposure necessary for effect in combination with ceftazidime, aztreonam, or ceftaroline fosamil. The PD driver of avibactam critical for restoring the activity of all three partner β-lactams was found to be time dependent rather than concentration dependent and was defined as the time that the concentration of avibactam exceeded a critical concentration threshold (%fT>C_T). The magnitude of the C_T and the time that this threshold needed to be exceeded to elicit particular PD endpoints varied depending on the model and the partner β-lactam. This review describes the preclinical studies used to determine the avibactam PK/PD target in combination with its β-lactam partners.

Ceftazidime-avibactam (CTZ-AVI) as a treatment for hospitalized adult patients with complicated intra-abdominal infections

Avibactam, a novel β-lactamase inhibitor, has recently been co-formulated with ceftazidime and approved for use in patients with complicated intra-abdominal and urinary tract infections, where no better treatment alternative exists. The basis for its FDA approval has been the extensive clinical experience with ceftazidime and the demonstration in vitro and in animal models that the addition of avibactam reverses resistance to ceftazidime in extended-spectrum β-lactamase and some carbapenemase-producing Enterobacteriaceae. Early clinical data are promising, with efficacy demonstrated in patients with complicated intra-abdominal and urinary tract infections. This review will summarize the in vitro, animal and clinical data available on this agent to date.

Aminoglycosides for Treatment of Bacteremia Due to Carbapenem-Resistant Klebsiella pneumoniae

Aminoglycoside treatment of carbapenem-resistant (CR) Klebsiella pneumoniae bacteremia was associated with a 70% rate (23/33) of 30-day survival. Successful treatment was associated with sources of bacteremia amenable to reliable aminoglycoside pharmacokinetics (P = 0.037), acute physiology and chronic health evaluation II (APACHE II) scores of <20 (P = 0.16), and nonfatal underlying diseases (P = 0.015). Success rates were 78% and 100% if ≥2 and all 3 factors were present, respectively. Clinicians may consider the use of aminoglycosides against CR K. pneumoniae bacteremia if strains are susceptible and the sources of infection are amenable to reliable pharmacokinetics.