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Background: There is a need for oral antibiotic agents that are effective against multidrug-resistant gram-negative uropathogens. Tebipenem pivoxil hydrobromide is an orally bioavailable carbapenem with activity against uropathogenic Enterobacterales, including extended-spectrum beta-lactamase-producing and fluoroquinolone-resistant strains., Methods: In this phase 3, international, double-blind, double-dummy trial, we evaluated the efficacy and safety of orally administered tebipenem pivoxil hydrobromide as compared with intravenous ertapenem in patients with complicated urinary tract infection or acute pyelonephritis. Patients were randomly assigned, in a 1:1 ratio, to receive oral tebipenem pivoxil hydrobromide (at a dose of 600 mg every 8 hours) or intravenous ertapenem (at a dose of 1 g every 24 hours) for 7 to 10 days (or up to 14 days in patients with bacteremia). The primary efficacy end point was overall response (a composite of clinical cure and favorable microbiologic response) at a test-of-cure visit (on day 19, within a ±2-day window) in the microbiologic intention-to-treat population. The noninferiority margin was 12.5%., Results: A total of 1372 hospitalized adult patients were enrolled; 868 patients (63.3%) were included in the microbiologic intention-to-treat population (50.8% of whom had complicated urinary tract infections and 49.2% of whom had pyelonephritis). An overall response was seen in 264 of 449 patients (58.8%) who received tebipenem pivoxil hydrobromide, as compared with 258 of 419 patients (61.6%) who received ertapenem (weighted difference, -3.3 percentage points; 95% confidence interval [CI], -9.7 to 3.2). Clinical cure at the test-of-cure visit was observed in 93.1% of the patients in the microbiologic intention-to-treat population who received tebipenem pivoxil hydrobromide and 93.6% of patients who received ertapenem (weighted difference, -0.6 percentage point; 95% CI, -4.0 to 2.8); the majority of patients with microbiologic response failures at the test-of-cure visit were asymptomatic patients with recurrent bacteriuria. Secondary and subgroup analyses were supportive of the primary analysis. Adverse events were observed in 25.7% of patients who received tebipenem pivoxil hydrobromide and in 25.6% of patients who received ertapenem; the most common adverse events were mild diarrhea and headache., Conclusions: Oral tebipenem pivoxil hydrobromide was noninferior to intravenous ertapenem in the treatment of complicated urinary tract infection and acute pyelonephritis and had a similar safety profile. (Funded by Spero Therapeutics and the Department of Health and Human Services; ADAPT-PO ClinicalTrials.gov number, NCT03788967.)., (Copyright © 2022 Massachusetts Medical Society.)

Avibactam is a non-β-lactam β-lactamase inhibitor that has been approved in combination with ceftazidime for the treatment of complicated intra-abdominal infections, complicated urinary tract infections, and nosocomial pneumonia, including ventilator-associated pneumonia. In Europe, ceftazidime-avibactam is also approved for the treatment of Gram-negative infections with limited treatment options. Selection and validation of the ceftazidime-avibactam dosage regimen was guided by an iterative process of population pharmacokinetic (PK) modelling, whereby population PK models for ceftazidime and avibactam were developed using PK data from clinical trials and updated periodically. These models were used in probability of target attainment (PTA) simulations using joint pharmacodynamic (PD) targets for ceftazidime and avibactam derived from preclinical data. Joint PTA was calculated based on the simultaneous achievement of the individual PK/PD targets (50% free time above the ceftazidime-avibactam MIC for ceftazidime and free time above a critical avibactam threshold concentration of 1 mg/liter for avibactam). The joint PTA analyses supported a ceftazidime-avibactam dosage regimen of 2,000 + 500 mg every 8 h by 2-h intravenous infusion for patients with creatinine clearance (CL CR ) >50 ml/min across all approved indications and modified dosage regimens for patients with CL CR ≤50 ml/min. Subgroup simulations for individual phase 3 patients showed that the dosage regimen was robust, with high target attainment (>95%) against MICs ≤8 mg/liter achieved regardless of older age, obesity, augmented renal clearance, or severity of infection. This review summarizes how the approved ceftazidime-avibactam dosage regimens were developed and validated using PK/PD targets, population PK modeling, and PTA analyses., (Copyright © 2019 American Society for Microbiology.)

Objectives: To describe the pharmacokinetic/pharmacodynamic (PK/PD) modelling and microbiological data that were used to support the recent European approval of ceftaroline fosamil 600 mg q8h by 2 h intravenous (iv) infusion for patients with complicated skin and soft tissue infections (cSSTIs) caused by Staphylococcus aureus with ceftaroline MICs of 2 or 4 mg/L, and the associated EUCAST MIC breakpoint update for q8h dosing (intermediate = 2 mg/L and resistant >2 mg/L)., Methods: A population PK model for ceftaroline and ceftaroline fosamil was developed using PK data from 21 clinical studies. The final model was used to simulate PTA in patients with cSSTI receiving ceftaroline fosamil 600 mg q12h by 1 h iv infusion or 600 mg q8h by 2 h iv infusion. PTA was calculated by MIC for S. aureus PK/PD targets derived from preclinical studies (27% fT>MIC for stasis, 31% fT>MIC for 1 log10 kill and 35% fT>MIC for 2 log10 kill) and compared with S. aureus ceftaroline MIC distributions from a 2013 global surveillance study., Results: The final population PK model based on 951 subjects adequately described ceftaroline and ceftaroline fosamil PK. High PTA (>90%) was predicted for the ceftaroline fosamil 600 mg q12h dosage regimen against S. aureus isolates with ceftaroline MICs ≤2 mg/L. Greater than 90% PTA was predicted for the ceftaroline fosamil 600 mg q8h dosage regimen against S. aureus with ceftaroline MICs ≤4 mg/L., Conclusions: The approved ceftaroline fosamil dosage regimens for adults and adolescents with cSSTI achieve high PTA against S. aureus at the associated EUCAST breakpoints.

Background: We conducted a meta-analysis of clinical trials of adults hospitalized with pneumonia outcomes research team (PORT) risk class 3-4 community-acquired pneumonia (CAP) receiving ceftaroline fosamil versus ceftriaxone., Methods: Three Phase III trials (clinicaltrials.gov registration numbers NCT00621504, NCT00509106 and NCT01371838) including 1916 hospitalized patients with CAP randomized 1:1 to empirical ceftaroline fosamil (600 mg every 12 h) or ceftriaxone (1-2 g every 24 h) for 5-7 days were included in the meta-analysis. Primary outcome was clinical response at the test-of-cure visit (8-15 days after end of treatment) in the PORT risk class 3-4 modified ITT (MITT) and clinically evaluable (CE) populations. Data were tested for heterogeneity (χ(2) test) and, if not significant, results were pooled and OR and 95% CI constructed. A logistic regression analysis assessed factors impacting cure rate and treatment interactions., Results: Clinical cure rates in each trial consistently favoured ceftaroline fosamil versus ceftriaxone, with no evidence of heterogeneity. In the meta-analysis, ceftaroline fosamil was superior to ceftriaxone in the MITT (OR: 1.66; 95% CI 1.34, 2.06; P < 0.001) and CE (OR: 1.65; 95% CI 1.26, 2.16; P < 0.001) populations. Results were consistent across various patient- and disease-related factors including patients' age and PORT score. Prior antimicrobial use within 96 h of starting study treatment was associated with diminished differences in cure rates between treatments., Conclusions: Ceftaroline fosamil was superior to ceftriaxone for empirical treatment of adults hospitalized with CAP. Receipt of prior antimicrobial therapy appeared to diminish the observed treatment effect., (© The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Background: Ceftriaxone with or without a macrolide antibiotic is a recommended treatment for patients with community-acquired pneumonia requiring hospital admission and intravenous antibiotic treatment. We aimed to assess the efficacy and safety of ceftaroline fosamil compared with ceftriaxone in the treatment of Asian patients admitted to hospital with community-acquired pneumonia., Methods: In this international, randomised, controlled, double-blind, phase 3, non-inferiority with nested superiority trial, adult Asian patients with Pneumonia Outcomes Research Team (PORT) risk class III-IV acute community-acquired pneumonia were randomly assigned (1:1) to receive intravenous ceftaroline fosamil (600 mg every 12 h) or ceftriaxone (2 g every 24 h) for 5-7 days. Patients were randomly assigned via centralised telephone and web-based system; patients and treating clinicians were masked to treatment allocation. Investigators who did study assessments remained masked to treatment allocation until completion of the study. The primary endpoint was clinical cure at the test-of-cure visit (8-15 days after last dose of study drug) in the clinically evaluable population. Non-inferiority of ceftaroline fosamil was defined as a lower limit of the two-sided 95% CI for the difference in the proportion of patients clinically cured of -10% or higher; if non-inferiority was achieved, superiority was to be concluded if the lower limit of the 95% CI was greater than 0%. This trial is registered with ClinicalTrials.gov, number NCT01371838., Findings: Between Dec 13, 2011, and April 26, 2013, 847 patients were enrolled at 64 centres in China, India, South Korea, Taiwan, and Vietnam, of whom 771 were randomly assigned and 764 received study treatment. In the clinically evaluable population (n=498) 217 (84%) of 258 patients in the ceftaroline fosamil group and 178 (74%) of 240 patients in the ceftriaxone group were clinically cured at the test-of-cure visit (difference 9·9%, 95% CI 2·8-17·1). The superiority of ceftaroline fosamil was consistent across all preplanned patient subgroup analyses (split by age 65 years, age 75 years, sex, PORT risk class, and previous antibiotic use) apart from patients younger than 65 years. The frequency of adverse events was similar between treatment groups and the safety results for ceftaroline fosamil were consistent with the cephalosporin class and previous clinical trial data., Interpretation: Ceftaroline fosamil 600 mg given every 12 h was superior to ceftriaxone 2 g given every 24 h for the treatment of Asian patients with PORT III-IV community-acquired pneumonia. These data suggest that ceftaroline fosamil should be regarded as an alternative to ceftriaxone in empirical treatment regimens for this patient population., Funding: AstraZeneca., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Antibiotic penetration to the infection site is critical for obtaining a good clinical outcome in patients with ventilator-associated pneumonia (VAP). Surprisingly few studies have quantified the penetration of β-lactam agents into the lung, as measured by the ratio of area under the concentration-time curve (AUC) in epithelial lining fluid (ELF) to AUC in plasma (AUC(ELF)/AUC(plasma) ratio). These have typically involved noninfected patients. This study examines the penetration and pharmacodynamics of meropenem in the ELF among patients with VAP. Meropenem plasma and ELF concentration-time data were obtained from patients in a multicenter clinical trial. Concentration-time profiles in plasma and ELF were simultaneously modeled using a three-compartment model with zero-order infusion and first-order elimination and transfer (big nonparametric adaptive grid [BigNPAG]). A Monte Carlo simulation was performed to estimate the range of ELF/plasma penetration ratios one would expect to observe in patients with VAP, as measured by the AUC(ELF)/AUC(plasma) ratio. The range of AUC(ELF)/AUC(plasma) penetration ratios predicted by the Monte Carlo simulation was large. The 10th percentile of lung penetration was 3.7%, while the 90th percentile of penetration was 178%. The variability of ELF penetration is such that if relatively high ELF exposure targets are required to attain multilog kill or resistance suppression for bacteria like Pseudomonas aeruginosa, then even receiving the largest licensed dose of meropenem with an optimal prolonged infusion may not result in target attainment for a substantial fraction of the population.