Cost-effectiveness analysis of ceftazidime/avibactam compared to imipenem as empirical treatment for complicated urinary tract infections

Ceftazidime with avibactam for treating severe aerobic Gram-negative bacterial infections: technology evaluation to inform a novel subscription-style payment model

Background

To limit the use of antimicrobials without disincentivising the development of novel antimicrobials, there is interest in establishing innovative models that fund antimicrobials based on an evaluation of their value as opposed to the volumes used. The aim of this project was to evaluate the population-level health benefit of ceftazidime-avibactam in the NHS in England, for the treatment of severe aerobic Gram-negative bacterial infections when used within its licensed indications. The results were used to inform National Institute for Health and Care Excellence guidance in support of commercial discussions regarding contract value between the manufacturer and NHS England.

Methods

The health benefit of ceftazidime-avibactam was first derived for a series of high-value clinical scenarios. These represented uses that were expected to have a significant impact on patients' mortality risks and health-related quality of life. Patient-level costs and health-related quality of life of ceftazidime-avibactam under various usage scenarios compared with alternative management strategies in the high-value clinical scenarios were quantified using decision modelling. Results were reported as incremental net health effects expressed in quality-adjusted life-years, which were scaled to 20-year population in quality-adjusted life-years using infection number forecasts based on data from Public Health England. The outcomes estimated for the high-value clinical scenarios were extrapolated to other expected uses for ceftazidime-avibactam.

Results

The clinical effectiveness of ceftazidime-avibactam relative to its comparators was estimated by synthesising evidence on susceptibility of the pathogens of interest to the antimicrobials in a network meta-analysis. In the base case, ceftazidime-avibactam was associated with a statistically significantly higher susceptibility relative to colistin (odds ratio 7.24, 95% credible interval 2.58 to 20.94). The remainder of the treatments were associated with lower susceptibility than colistin (odds ratio < 1). The results were sensitive to the definition of resistance and the studies included in the analysis. In the base case, patient-level benefit of ceftazidime-avibactam was between 0.08 and 0.16 quality-adjusted life-years, depending on the site of infection and the usage scenario. There was a high degree of uncertainty surrounding the benefits of ceftazidime-avibactam across all subgroups, and the results were sensitive to assumptions in the meta-analysis used to estimate susceptibility. There was substantial uncertainty in the number of infections that are suitable for treatment with ceftazidime-avibactam, so population-level results are presented for a range of scenarios for the current infection numbers, the expected increases in infections over time, and rates of emergence of resistance. The population-level benefit varied substantially across the scenarios, from 531 to 2342 quality-adjusted life-years over 20 years.

Conclusion

This work has provided quantitative estimates of the value of ceftazidime-avibactam within its areas of expected usage within the NHS.

Limitations

Given existing evidence, the estimates of the value of ceftazidime-avibactam are highly uncertain.

Future work

Future evaluations of antimicrobials would benefit from improvements to NHS data linkages, research to support appropriate synthesis of susceptibility studies, and application of routine data and decision modelling to assess enablement value.

Study registration

No registration of this study was undertaken.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Policy Research Programme (NIHR award ref: NIHR135592), conducted through the Policy Research Unit in Economic Methods of Evaluation in Health and Social Care Interventions, PR-PRU-1217-20401, and is published in full in Health Technology Assessment; Vol. 28, No. 73. See the NIHR Funding and Awards website for further award information.

Cefiderocol for treating severe aerobic Gram-negative bacterial infections: technology evaluation to inform a novel subscription-style payment model

Background

To limit the use of antimicrobials without disincentivising the development of novel antimicrobials, there is interest in establishing innovative models that fund antimicrobials based on an evaluation of their value as opposed to the volumes used. The aim of this project was to evaluate the population-level health benefit of cefiderocol in the NHS in England, for the treatment of severe aerobic Gram-negative bacterial infections when used within its licensed indications. The results were used to inform the National Institute for Health and Care Excellence guidance in support of commercial discussions regarding contract value between the manufacturer and NHS England.

Methods

The health benefit of cefiderocol was first derived for a series of high-value clinical scenarios. These represented uses that were expected to have a significant impact on patients' mortality risks and health-related quality of life. The clinical effectiveness of cefiderocol relative to its comparators was estimated by synthesising evidence on susceptibility of the pathogens of interest to the antimicrobials in a network meta-analysis. Patient-level costs and health outcomes of cefiderocol under various usage scenarios compared with alternative management strategies were quantified using decision modelling. Results were reported as incremental net health effects expressed in quality-adjusted life-years, which were scaled to 20-year population values using infection number forecasts based on data from Public Health England. The outcomes estimated for the high-value clinical scenarios were extrapolated to other expected uses for cefiderocol.

Results

Among Enterobacterales isolates with the metallo-beta-lactamase resistance mechanism, the base-case network meta-analysis found that cefiderocol was associated with a lower susceptibility relative to colistin (odds ratio 0.32, 95% credible intervals 0.04 to 2.47), but the result was not statistically significant. The other treatments were also associated with lower susceptibility than colistin, but the results were not statistically significant. In the metallo-beta-lactamase Pseudomonas aeruginosa base-case network meta-analysis, cefiderocol was associated with a lower susceptibility relative to colistin (odds ratio 0.44, 95% credible intervals 0.03 to 3.94), but the result was not statistically significant. The other treatments were associated with no susceptibility. In the base case, patient-level benefit of cefiderocol was between 0.02 and 0.15 quality-adjusted life-years, depending on the site of infection, the pathogen and the usage scenario. There was a high degree of uncertainty surrounding the benefits of cefiderocol across all subgroups. There was substantial uncertainty in the number of infections that are suitable for treatment with cefiderocol, so population-level results are presented for a range of scenarios for the current infection numbers, the expected increases in infections over time and rates of emergence of resistance. The population-level benefits varied substantially across the base-case scenarios, from 896 to 3559 quality-adjusted life-years over 20 years.

Conclusion

This work has provided quantitative estimates of the value of cefiderocol within its areas of expected usage within the NHS.

Limitations

Given existing evidence, the estimates of the value of cefiderocol are highly uncertain.

Future work

Future evaluations of antimicrobials would benefit from improvements to NHS data linkages; research to support appropriate synthesis of susceptibility studies; and application of routine data and decision modelling to assess enablement value.

Study registration

No registration of this study was undertaken.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment Policy Research Programme (NIHR award ref: NIHR135591), conducted through the Policy Research Unit in Economic Methods of Evaluation in Health and Social Care Interventions, PR-PRU-1217-20401, and is published in full in Health Technology Assessment; Vol. 28, No. 28. See the NIHR Funding and Awards website for further award information.

Carbapenem-Resistant Enterobacteriaceae in Urinary Tract Infections: From Biological Insights to Emerging Therapeutic Alternatives

Urinary tract infections (UTIs) are the second most frequent type of infection observed in clinical practice. Gram-negative Enterobacteriaceae are common pathogens in UTIs. Excessive antibiotic use in humans and animals, poor infection control, and increased global travel have accelerated the spread of multidrug-resistant strains (MDR). Carbapenem antibiotics are commonly considered the last line of defense against MDR Gram-negative bacteria; however, their efficacy is now threatened by the increasing prevalence of carbapenem-resistant Enterobacteriaceae (CRE). This comprehensive review aims to explore the biological mechanisms underlying carbapenem resistance and to present a focus on therapeutic alternatives currently available for complicated UTIs (cUTIs). A comprehensive bibliographic search was conducted on the PubMed/MEDLINE, Scopus, and Web of Science databases in December 2023. The best evidence on the topic was selected, described, and discussed. Analyzed with particular interest were the clinical trials pivotal to the introduction of new pharmacological treatments in the management of complicated cUTIs. Additional suitable articles were collected by manually cross-referencing the bibliography of previously selected papers. This overview provides a current and comprehensive examination of the treatment options available for CRE infections, offering a valuable resource for understanding this constantly evolving public health challenge.

Cost-effectiveness analysis of ceftazidime avibactam versus colistin in carbapenem-resistant enterobacteriaceae in Iran

INTRODUCTION

Ceftazidime avibactam (CA) is an effective treatment against carbapenem-resistant Enterobacteriaceae (CRE), but its cost-effectiveness is unclear. This study was performed to evaluate the cost-effectiveness of CA against the best available treatment colistin (Col) for patients with CRE-related infections in Iran.

METHODOLOGY

A model of a decision tree was designed to evaluate the cost-effectiveness of CA in CRE patients over a period of 5 years. The Iran health system was the perspective of the study, and the discount rates of 5.8% and 3% were considered for the data of cost and utility, respectively. The clinical inputs were obtained from a prospective observational study. We established the costs of medical services and medical tariffs of Iran's health system, and obtained the rate of medical service resources used by patients from specialists. The results of this model included the quality-adjusted life years (QALYs), increasing costs, and incremental cost-utility ratio (ICUR). We also performed the deterministic and probabilistic sensitivity analyses.

RESULTS

CA reduced the burden of related to treatment failure and the need for treatment of nephrotoxicity and chronic failure, whereas, the costs related to drug procurement and long-term care (due to longer survival) increased. Treatment with CA versus Col resulted in a 53% increase in QALYs and $425 in costs, leading to an ICUR equal to 798 $/QALYs. Sensitivity analyses proved the model's strength and indicated that the cost-effectiveness of CA can reach 88% when paying 1111 $/QALY. Budget impact analysis estimated CA regimen will increase the health system costs by $1,270,462 in 5 years.

CONCLUSION

In Iranian settings, CA can significantly increase the quality of life and patients' survival; therefore, in comparison to the Col drug regimen, CA is a cost-effective strategy.

Cost-effectiveness analysis of ceftazidime-avibactam as definitive treatment for treatment of carbapenem-resistant Klebsiella pneumoniae bloodstream infection

Background

Ceftazidime-avibactam (CAZ-AVI) is a novel antibiotic that has been confirmed in the United States and China for use in patients with carbapenem-resistant Klebsiella pneumoniae (CRKP) bloodstream infection (BSI). However, the cost-effectiveness of CAZ-AVI is unknown in China. This study aimed to evaluate the cost-effectiveness of CAZ-AVI compared to polymyxin B (PMB) monotherapy or PMB-based therapy for the treatment of CRKP BSI from the Chinese healthcare perspective.

Methods

A hybrid decision tree and Markov model were constructed for a hypothetical cohort of patients with CRKP BSI. The time horizon of the Markov model was 5 years with an annual discount rate of 5% used in both costs and quality-adjusted life-years (QALYs). The model data was derived from published literature and publicly available database. Regimens with an incremental cost-effectiveness ratio (ICER) lower than the willingness-to-pay (WTP) threshold of $ 11,600 per QALY were considered cost-effective. Deterministic and probabilistic sensitivity analyses were performed to examine the robustness of model analysis.

Results

In the base-analysis, CAZ-AVI provided an additional 60 QALYs and reduced the cost by $ 2,218,300, yielding an ICER of $ -36,730.9/QALY, well below the WTP threshold of $ 11,600 per QALY when compared with PMB-based therapy. CAZ-AVI provided an additional 350 QALYs and increased the cost of $ 208,400, producing an ICER of $ 591.7/QALY that was below the WTP threshold compared to PMB monotherapy. At a $ 11,600/QALY threshold, results were sensitive to the cost of PMB-based strategy, the cost of CAZ-AVI strategy, the probability of cure with CAZ-AVI, and the probability of cure with PMB or PMB-based therapy. CAZ-AVI was an optimal regimen in 76.9% and 80.8% of 10,000 Monte Carlo simulations at $ 11,600/QALY and $ 34,800/QALY, respectively. Meanwhile, CAZ-AVI was cost-effective at the WTP thresholds of all 31 Chinese provinces in 61.4% (Gansu) to 83.1% (Beijing) of simulations.

Conclusions

Ceftazidime-avibactam is expected to be a cost-effective treatment compared with PMB monotherapy or PMB-based therapy for CRKP BSI from the Chinese healthcare perspective.

Efficacy and safety of piperacillin-tazobactam compared with meropenem in treating complicated urinary tract infections including acute pyelonephritis due to extended-spectrum β-lactamase-producing Enterobacteriaceae

Introduction

Extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae pose a huge threat to human health, especially in the context of complicated urinary tract infections (cUTIs). Carbapenems and piperacillin-tazobactam (PTZ) are two antimicrobial agents commonly used to treat cUTIs.

Methods

A monocentric retrospective cohort study focused on the treatment of cUTIs in adults was conducted from January 2019 to November 2021. Patients with a positive urine culture strain yielding ≥ 103 colony-forming units per milliliter (CFU/mL), and sensitive to PTZ and carbapenems, were included. The primary endpoint was clinical success after antibiotic therapy. The secondary endpoint included rehospitalization and 90-day recurrence of cUTIs caused by ESBL-producing Enterobacteriaceae.

Results

Of the 195 patients included in this study, 110 were treated with PTZ while 85 were administered meropenem. The rate of clinical cure was similar between the PTZ and meropenem groups (80% vs. 78.8%, p = 0.84). However, the PTZ group had a lower duration of total antibiotic use (6 vs. 9; p < 0.01), lower duration of effective antibiotic therapy (6 vs. 8; p < 0.01), and lower duration of hospitalization (16 vs. 22; p < 0.01).

Discussion

In terms of adverse events, the safety of PTZ was higher than that of meropenem in the treatment of cUTIs.

In vitro activity of ceftazidime-avibactam against Gram-negative strains in patients with complicated urinary tract infection and complicated intra-abdominal infection in Colombia 2014-2018

Ceftazidime/avibactam (CAZ/AVI) has excellent in vitro activity against enterobacterales and Pseudomonas aeruginosa. The study aimed to analyze the in vitro antimicrobial activity of CAZ/AVI and other antibiotics against isolates of enterobacterales and P. aeruginosa from patients with complicated urinary tract infection (cUTI) and complicated intra-abdominal infection (cIAI) in Colombian hospitals between 2014 and 2018, using the Antimicrobial Testing Leadership and Surveillance (ATLAS) database. Enterobacterales and P. aeruginosa samples were obtained from patients with cUTI and cIAI. Susceptibility was determined using The Clinical and Laboratory Standards Institute (CLSI) breakpoints. Meropenem-non-susceptible isolates were screened for extended-spectrum β-lactamase (ESBL) production. Isolates that were positive for ESBL activity were examined by Multiplex Polymerase Chain Reaction (Multiplex PCR) to detect genotypic resistance. A total of 565 Enterobacterales and 95 P. aeruginosa from patients with cUTI and 345 Enterobacterales and 65 P. aeruginosa from patients with cIAI were isolated. In vitro activity showed susceptibility to CAZ/AVI greater than 99% for Enterobacterales and in lower percentages for P. aeruginosa in cUTI (78.46%) and cIAI (83.33%). CAZ/AVI showed good in vitro activity against multidrug-resistant (MDR) Enterobacterales and P. aeruginosa in patients with cUTI and cIAI.

Cost-Effectiveness Analysis of New Beta-Lactam Beta-Lactamase Inhibitor Antibiotics Versus Colistin for the Treatment of Carbapenem-Resistant Infections

Introduction: Carbapenem-resistant organisms (CROs) present a serious public health problem. Limited treatment options has led to increased use of colistin and polymyxin. Since 2014, the US Food and Drug Administration approved 4 new beta-lactam beta-lactamase inhibitor (BLBLI) combination antibiotics with activity against CROs. These new antibiotics have been shown to be more effective and less toxic than colistin and polymyxin but are considerably more expensive. This study evaluated the cost-effectiveness of the new BLBLIs versus colistin-based therapy for the treatment of CROs. Methods: A decision-tree microsimulation model was used to evaluate the cost effectiveness of the new BLBLIs versus colistin-based therapy for the treatment of CROs. Treatment groups differed in risk of mortality and risk of an acute kidney injury (AKI). The relative risk of mortality was determined by creating a meta-analysis comparing new BLBLIs to colistin. Cost inputs included medication costs and the cost to treat an AKI. The primary outcomes include quality-adjusted life years (QALYs) and incremental cost-effectiveness ratio (ICER). Model inputs included: clinical outcomes and adverse events (30-day mortality and AKI); cost of treatment and adverse drug events; and health utilities. A 3% discount was applied for outcomes. A lifetime horizon was used from the perspective of the US healthcare system with a willingness-to-pay (WTP) threshold of $100 000. A sensitivity analysis was done to incorporate uncertainty. Results: The meta-analysis found the treatment with a new BLBLI was associated with a 50% decrease in the relative risk of 30-day mortality compared to colistin (RR 0.47, 95% CI 0.25-0.88). Treatment with a new BLBLI cost $16 200 and produced 11.5 QALYs, on average. The average colistin based regimen cost $3500 and produced 8.3 QALYs. The new BLBLIs were determined to be cost-effective with an ICER of $3900 per QALY gained. Treatment with a BLBLI remained cost-effective under all uncertainty scenarios tested. Conclusion: New BLBLIs are cost-effective compared to colistin for the treatment of CROs and are associated with improved mortality and fewer AKI events. The use of colistin should be reserved for cases where new BLBLIs are not available or there is documented resistance to these new antibiotics.

Mathematical model of the cost-effectiveness of the BioFire FilmArray Blood Culture Identification (BCID) Panel molecular rapid diagnostic test compared with conventional methods for identification of Escherichia coli bloodstream infections

BACKGROUND

Gram-negative pathogens, such as Escherichia coli, are common causes of bloodstream infections (BSIs) and increasingly demonstrate antimicrobial resistance. Molecular rapid diagnostic tests (mRDTs) offer faster pathogen identification and susceptibility results, but higher costs compared with conventional methods. We determined the cost-effectiveness of the BioFire FilmArray Blood Culture Identification (BCID) Panel, as a type of mRDT, compared with conventional methods in the identification of E. coli BSIs.

METHODS

We constructed a decision analytic model comparing BCID with conventional methods in the identification and susceptibility testing of hospitalized patients with E. coli BSIs from the perspective of the public healthcare payer. Model inputs were obtained from published literature. Cost-effectiveness was calculated by determining the per-patient admission cost, the QALYs garnered and the incremental cost-effectiveness ratios (ICERs) where applicable. Monte Carlo probabilistic sensitivity analyses and one-way sensitivity analyses were conducted to assess the robustness of the model. All costs reflect 2019 Canadian dollars.

RESULTS

The Monte Carlo probabilistic analyses resulted in cost savings ($27 070.83 versus $35 649.81) and improved QALYs (8.65 versus 7.10) in favour of BCID. At a willingness to pay up to $100 000, BCID had a 72.6%-83.8% chance of being cost-effective. One-way sensitivity analyses revealed length of stay and cost per day of hospitalization to have the most substantial impact on costs and QALYs.

CONCLUSIONS

BCID was found to be cost-saving when used to diagnose E. coli BSI compared with conventional testing. Cost savings were most influenced by length of stay and cost per day of hospitalization.

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.

Choosing Optimal Antibiotics for the Treatment of Patients Infected With Enterobacteriaceae: A Network Meta-analysis and Cost-Effectiveness Analysis

Overuse of carbapenems has led to the increasing carbapenem-resistant Enterobacteriaceae. It is still unknown whether other antibiotics [especially novel β-lactam/β-lactamase inhibitor combinations (BL/BLIs)] are better than carbapenems in the treatment of Enterobacteriaceae. A systematic literature search was performed to identify randomized controlled trials (RCTs) assessing the efficacy and safety of any antibiotics on Enterobacteriaceae infections. We carried out a traditional paired meta-analysis to compare ceftazidime/avibactam to comparators. Network meta-analysis (NMA) was conducted to integrate direct and indirect evidence of all interventions. Moreover, cost-effectiveness analysis using a combined decision analytical Markov model was completed for the treatment of patients with complex urinary tract infection (cUTI). A total of 25 relevant RCTs were identified, comprising 15 different interventions. Ceftazidime/avibactam exhibited comparable efficacy and safety with comparators (carbapenems) in the paired meta-analysis. In the NMA, the surface under the cumulative ranking curve probabilities showed that in terms of efficacy, the interventions with the highest-ranking were meropenem/vaborbactam, meropenem, imipenem/cilastatin, ceftriaxone, ceftazidime/avibactam, and ceftolozane/tazobactam [but no significant difference between any two antibiotics (p > 0.05)]. Regarding safety, ceftazidime/avibactam had a higher incidence of adverse events than that of piperacillin/tazobactam (relative risk = 0.74, 95% confidence interval = 0.59–0.94). Based on drug and hospitalization costs in China, the incremental cost-effectiveness ratio per quality-adjusted life-year gained in the patients with cUTI for meropenem, ceftazidime/avibactam, and ceftolozane/tazobactam compared to imipenem/cilastatin were US$579, US$24569, and US$29040, respectively. The role of these BL/BLIs to serve as alternatives to carbapenems requires large-scale and high-quality studies to validate.

Guidance for Demonstrating the Societal Value of new Antibiotics

Given that antibiotic use is associated with externalities, standard economic evaluation which considers costs and health gains accruing to patients under-values antibiotics. Informed by a scoping review, this discussion paper aims to identify the societal value elements of antibiotics and to provide guidance on how these value elements can be incorporated in economic evaluation. With a view to appropriately quantify the societal value of antibiotics, there is a need for good practice guidelines on the methodology of economic evaluation for such products. We argue that it is important to assess antibiotics at population level to account for their transmission, diversity, insurance, spectrum, novel action and enablement values. In addition to the value of antibiotics to infected patients, economic evaluations need to use modeling approaches to explore the impact of different modes of employing new and existing antibiotics (for example, as last resort treatment) on disease transmission and resistance development in current and future patients. Hence, assessing the value of antibiotics also involves an ethical dimension. Further work is required about how the multiple value elements of antibiotics are linked to each other and how they can be aggregated.