Analysis of the clinical application of ceftazidime-avibactam in China.

BACKGROUND: The efficacy and safety of ceftazidime-avibactam were mainly reported in phase II and phase III clinical trials, rarely in the real-world study. The limited real-world study which evaluated the clinical response of this drug shown inconsistent results. This study aimed to investigate the rationality of the clinical use of ceftazidime-avibactam and to evaluate its clinical response in the treatment of multidrug-resistant gram-negative bacteria (MDR-GNB) infections in China. METHODS: This retrospective study evaluated the outcomes of adult patients with MDR-GNB infections treated with ceftazidime-avibactam during September 2018 to August 2020. Patients' characteristics, comorbidities, microbes, laboratory indicators and medication information were collected. The rationality of ceftazidime-avibactam clinical use, and its clinical response in the treatment of MDR-GNB infections were analyzed. RESULTS: A total of 30 patients were included in this study, of which, 66.6% received target treatment, 26.7% received empirical treatment, and 6.7% received treatment with no indication. Only 50.0% (11/22) of patients were administrated the recommended dose according to the drug instruction or guidelines, at a median treatment duration of 10 days (range: 2-74 days). The most common source of infection was pneumonia (53.6%, 15/28). Carbapenem-resistant Klebsiella pneumoniae was the predominant pathogen (65%, 13/20). A total of 16 patients (61.5%) achieved clinical response. Patients received target treatment had higher clinical response rate than that of patients received empirical treatment (77.8% vs 25.0%, P = 0.026). A total of 11 patients (61.1%) achieved microbiological response. One patient occurred gastrointestinal adverse reactions. CONCLUSIONS: It is necessary to strengthen the monitor of the clinical application of ceftazidime-avibactam, such as the appropriate indication, reasonable dosage and duration, to improve its clinical outcome. Our results showed that ceftazidime-avibactam might be a potencial choice for the MDR-GNB infections. However, further research are still needed to identify its efficacy and safety in the real world.

Evaluation of the post-antibiotic effect in vivo for the combination of a ß-lactam antibiotic and a ß-lactamase inhibitor: ceftazidime-avibactam in neutropenic mouse thigh and lung infections.

The post-antibiotic effect (PAE) of ceftazidime-avibactam in vivo was evaluated using models of thigh- and lung-infection with Pseudomonas aeruginosa in neutropenic mice. In thigh-infected mice, the PAE was negative (-2.18 to -0.11 h) for three of four strains: caused by a 'burst' of rapid bacterial growth after the drug concentrations had fallen below their pre-specified target values. With lung infection, PAE was positive, and longer for target drug concentrations in ELF (>2 h) than plasma (1.69-1.88 h). The time to the start of regrowth was quantified as a new parameter, PAER, which was positive (0.35-1.00 h) in both thigh- and lung-infected mice. In the context that measurements of the PAE of ß-lactam/ß-lactamase inhibitor combinations in vivo have not previously been reported, it is noted that the negative values were consistent with previous measurements of the PAE of ceftazidime-avibactam in vitro and of ceftazidime alone in vivo.

Safety and Efficacy of Ceftazidime-Avibactam Plus Metronidazole in the Treatment of Children ≥3 Months to <18 Years With Complicated Intra-Abdominal Infection: Results From a Phase 2, Randomized, Controlled Trial.

BACKGROUND: Ceftazidime-avibactam plus metronidazole is effective in the treatment of complicated intra-abdominal infection (cIAI) in adults. This single-blind, randomized, multicenter, phase 2 study (NCT02475733) evaluated the safety, efficacy and pharmacokinetics of ceftazidime-avibactam plus metronidazole in children with cIAI. METHODS: Hospitalized children (≥3 months to <18 years) with cIAI were randomized 3:1 to receive intravenous ceftazidime-avibactam plus metronidazole, or meropenem, for a minimum of 72 hours (9 doses), with optional switch to oral therapy thereafter for a total treatment duration of 7-15 days. Safety and tolerability were assessed throughout the study, along with clinical and microbiologic outcomes, and pharmacokinetics. A blinded observer determined adverse event (AE) causality, and clinical outcomes up to the late follow-up visit. RESULTS: Eighty-three children were randomized and received study drug (61 ceftazidime-avibactam plus metronidazole and 22 meropenem); most (90.4%) had a diagnosis of appendicitis. Predominant Gram-negative baseline pathogens were Escherichia coli (79.7%) and Pseudomonas aeruginosa (33.3%); 2 E. coli isolates were ceftazidime-non-susceptible. AEs occurred in 52.5% and 59.1% of patients in the ceftazidime-avibactam plus metronidazole and meropenem groups, respectively. Serious AEs occurred in 8.2% and 4.5% of patients, respectively; none was considered drug related. No deaths occurred. Favorable clinical/microbiologic responses were observed in ≥90% of patients in both treatment groups at end-of-intravenous treatment and test-of-cure visits. CONCLUSIONS: Ceftazidime-avibactam plus metronidazole was well tolerated, with a safety profile similar to ceftazidime alone, and appeared effective in pediatric patients with cIAI due to Gram-negative pathogens, including ceftazidime-non-susceptible strains.

Effectiveness of ceftazidime/avibactam as salvage therapy for treatment of infections due to OXA-48 carbapenemase-producing Enterobacteriaceae.

Background: Experience in real clinical practice with ceftazidime/avibactam is limited, and there are even fewer data on infections due to OXA-48-producing Enterobacteriaceae. Methods: We designed an observational study of a prospectively collected cohort of adult patients receiving ceftazidime/avibactam in our centre. Only the first treatment course of each patient was analysed. Efficacy and safety were evaluated as 14 and 30 day mortality, recurrence rate at 90 days, resistance development and occurrence of adverse effects. Results: Fifty-seven patients were treated with ceftazidime/avibactam. The median age was 64 years (range 26-86), 77% were male and the median Charlson index was 3. The most frequent sources of infection were intra-abdominal (28%), followed by respiratory (26%) and urinary (25%). Thirty-one (54%) patients had a severe infection (defined as presence of sepsis or septic shock). Most patients received ceftazidime/avibactam as monotherapy (81%) and the median duration of treatment was 13 days. Mortality at 14 days was 14%. In multivariate analysis, the only mortality risk factor was INCREMENT-CPE score >7 (HR 11.7, 95% CI 4.2-20.6). There was no association between mortality and monotherapy with ceftazidime/avibactam. The recurrence rate at 90 days was 10%. Ceftazidime/avibactam resistance was not detected in any case and only two patients developed adverse events related to treatment. Conclusions: Ceftazidime/avibactam shows promising results, even in monotherapy, for the treatment of patients with severe infections due to OXA-48-producing Enterobacteriaceae and limited therapeutic options. The emergence of resistance to ceftazidime/avibactam was not observed.

The CRH1 antagonist GSK561679 increases human fear but not anxiety as assessed by startle.

Fear to predictable threat and anxiety to unpredictable threat reflect distinct processes mediated by different brain structures, the central nucleus of the amygdala and the bed nucleus of the stria terminalis (BNST), respectively. This study tested the hypothesis that the corticotropin-releasing factor (CRF1) antagonist GSK561679 differentially reduces anxiety but increases fear in humans. A total of 31 healthy females received each of four treatments: placebo, 50 mg GSK561679 (low-GSK), 400 mg GSK561679 (high-GSK), and 1 mg alprazolam in a crossover design. Participants were exposed to three conditions during each of the four treatments. The three conditions included one in which predictable aversive shocks were signaled by a cue, a second during which shocks were administered unpredictably, and a third condition without shock. Fear and anxiety were assessed using the acoustic startle reflex. High-GSK had no effect on startle potentiation during unpredictable threat (anxiety) but increased startle potentiation during the predictable condition (fear). Low-GSK did not affect startle potentiation across conditions. Consistent with previous findings, alprazolam reduced startle potentiation during unpredictable threat but not during predictable threat. The increased fear by high-GSK replicates animal findings and suggests a lift of the inhibitory effect of the BNST on the amygdala by the CRF1 antagonist.

A randomized invasive cardiac electrophysiology study of the combined ion channel blocker AZD1305 in patients after catheter ablation of atrial flutter.

BACKGROUND: This study assessed the cardiac electrophysiological and hemodynamic effects of an intravenous infusion of the combined ion channel blocker AZD1305. METHODS: After successful ablation of atrial flutter, patients were randomized to receive placebo (n = 12) or AZD1305 (n = 38) in 4 ascending dose groups. Electrophysiological and hemodynamic measurements were performed before and commencing 20 minutes after start of infusion. RESULTS: Left atrial effective refractory period increased dose and the primary outcome measure increased dose and plasma concentration dependently, with a mean increase of 55 milliseconds in dose group 3. There was a corresponding increase in right atrial effective refractory period of 84 milliseconds. The right ventricular effective refractory period and the paced QT interval also increased dose and concentration dependently, by 59 and 70 milliseconds, respectively, in dose group 3. There were indications of moderate increases of atrial, atrioventricular nodal, and ventricular conduction times. No consistent changes in intracardiac pressures were observed, but there was a small transient decrease in systolic blood pressure. Adverse events were consistent with the study population and procedure, and there were no signs of proarrhythmia despite marked delay in ventricular repolarization in some individuals. CONCLUSIONS: AZD1305 shows electrophysiological characteristics indicative of potential antiarrhythmic efficacy in atrial fibrillation.