Real-world evaluation of imipenem/cilastatin/relebactam across US medical centres.

We assessed 160 patients who received imipenem/cilastatin/relebactam for ≥2 days. At treatment initiation, the median Charlson Comorbidity Index was 5, 45% were in the intensive care unit, and 19% required vasopressor support. The in-hospital mortality rate was 24%. These data advance our understanding of real-world indications and outcomes of imipenem/cilastatin/relebactam use.

Advances in novel antibiotics to treat multidrug-resistant gram-negative bacterial infections.

Antimicrobial resistance is a growing threat to public health and an increasingly common problem for acute care physicians to confront. Several novel antibiotics have been approved in the past decade to combat these infections; however, physicians may be unfamiliar with how to appropriately utilize them. The purpose of this review is to evaluate novel antibiotics active against resistant gram-negative bacteria and highlight clinical information regarding their use in the acute care setting. This review focuses on novel antibiotics useful in the treatment of infections caused by resistant gram-negative organisms that may be seen in the acute care setting. These novel antibiotics include ceftolozane/tazobactam, ceftazidime/avibactam, meropenem/vaborbactam, imipenem/cilistatin/relebactam, cefiderocol, plazomicin, eravacycline, and omadacycline. Acute care physicians should be familiar with these novel antibiotics so they can utilize them appropriately.

Reversible black tongue: A little known side effect of imipenem/cilastatin and evidence for novel mode of action.

WHAT IS KNOWN AND OBJECTIVE: Black tongue syndrome (BT) is a rare and self-limiting disorder which can result from physiological and metabolic condition and ingestion of toxic substances. Medications are the most common cause of BT. CASE SUMMARY: A 39-year-old male patient presented with BT after the initiation of imipenem/cilastatin. Within one week of cessation of these drugs, the patient's tongue returned to a normal colour. WHAT IS NEW AND CONCLUSION: This is the first case of BT induced by imipenem/cilastatin. Withdrawal of the combination is likely to reverse the condition.

Pharmacokinetics and Tolerability of Intravenous Sulbactam-Durlobactam with Imipenem-Cilastatin in Hospitalized Adults with Complicated Urinary Tract Infections, Including Acute Pyelonephritis.

Durlobactam (DUR; ETX2514) is a novel ß-lactamase inhibitor with broad-spectrum activity against Ambler class A, C, and D ß-lactamases. Durlobactam restores the in vitro activity of sulbactam (SUL) against members of the Acinetobacter baumannii-A. calcoaceticus complex (ABC). Sulbactam (SUL)-durlobactam (SUL-DUR) is under development for the treatment of ABC infections. Eighty patients with complicated urinary tract infection (cUTI), including acute pyelonephritis (AP), were randomized 2:1 to receive SUL-DUR at 1 g/1 g intravenously (i.v.) or placebo every 6 h (q6h) for 7 days and background therapy with imipenem-cilastatin (IMI) at 500 mg i.v. q6h to evaluate the tolerability of SUL-DUR in hospitalized patients. Patients with bacteremia could receive up to 14 days of therapy. SUL-DUR tolerability and the values of various pharmacokinetic (PK) parameters were determined. Efficacy was recorded at the test-of-cure (TOC) visit. SUL-DUR was well tolerated, with no serious adverse events (AEs) being reported. Headache (5.7%), nausea (3.8%), diarrhea (3.8%), and vascular pain (3.8%) were the most common drug-related AEs with SUL-DUR and were mostly of mild or moderate severity. The PK profile of DUR and SUL in hospitalized patients was consistent with observations in healthy volunteers. Overall success in the microbiological modified intent-to-treat (m-MITT) population was similar between the groups, as would be expected with IMI background therapy in all patients (overall success at the TOC visit, 76.6% [n = 36] with SUL-DUR and 81.0% [n = 17] with placebo). SUL-DUR in combination with IMI was well tolerated in patients with cUTIs. The pharmacokinetics of SUL-DUR observed in hospitalized patients was similar to that observed in healthy volunteers. (This study has been registered at ClinicalTrials.gov under identifier NCT03445195.).

Use of inhaled imipenem/cilastatin in pediatric patients with cystic fibrosis: A case series.

Mycobacterium abscessus is a rapidly-growing, virulent, non-tuberculous mycobacterium that causes progressive inflammatory lung damage and significant decline in lung functionin patients with cystic fibrosis. M. abscessus complex pulmonary infections are notoriously difficult to treat, and while many antibiotics are approved for children, drug allergies or intolerances can prohibit their use. Intravenous imipenem/cilastatin is among the preferred antibiotics for treatment of M. abscessus, however, its use may result in systemic toxicities including hepatic injury and gastrointestinal effects. Case reports document the successful use of inhaled imipenem/cilastatin in adult cystic fibrosis and non- cystic fibrosis patients with non- M. abscessus pulmonary infections. To our knowledge, similar evidence does not exist for pediatric patients. In this case series, we describe two pediatric patients with cystic fibrosis and previous intolerance or lack of response to standard therapies who received inhaled imipenem/cilastatin for the treatment of chronic M. abscessus infection.

Population Pharmacokinetics and Dosing Optimization of Imipenem in Children with Hematological Malignancies.

Imipenem is widely used for the treatment of children with serious infections. Currently, studies on the pharmacokinetics of imipenem in children with hematological malignancies are lacking. Given the significant impact of disease on pharmacokinetics and increased resistance, we aimed to conduct a population pharmacokinetic study of imipenem and optimize the dosage regimens for this vulnerable population. After children were treated with imipenem-cilastatin (IMP-CS), blood samples were collected from the children and the concentrations of imipenem were quantified using high-performance liquid chromatography with UV detection. Then, a population-level pharmacokinetic analysis was conducted using NONMEM software. Data were collected from 56 children (age range, 2.03 to 11.82 years) with hematological malignancies to conduct a population pharmacokinetic analysis. In this study, a two-compartment model that followed first-order elimination was found to be the most suitable. The parameters of current weight, age, and creatinine elimination rate were significant covariates that influenced imipenem pharmacokinetics. As a result, 41.4%, 56.1%, and 67.1% of the children reached the pharmacodynamic target (the percentage of the time during the total dosing interval that the free drug concentration remains above the MIC of 70%) against sensitive pathogens with an MIC of 0.5 mg/liter with imipenem at 15, 20, and 25 mg/kg of body weight every 6 h (q6h), respectively. However, only 11.1% of the children achieved the pharmacodynamic target against Pseudomonas aeruginosa isolates with an MIC of 2 mg/liter at a dose of 25 mg/kg q6h. The population pharmacokinetics of imipenem were assessed in children. The current dosage regimens of imipenem result in underdosing against resistant pathogens, including Pseudomonas aeruginosa and Acinetobacter baumannii However, for sensitive pathogens, imipenem has an acceptable pharmacodynamic target rate at a dosage of 25 mg/kg q6h. (The study discussed in this paper has been registered at ClinicalTrials.gov under identifier NCT03113344.).

PHARMECMO: Therapeutic drug monitoring and adequacy of current dosing regimens of antibiotics in patients on Extracorporeal Life Support.

INTRODUCTION: Optimisation of antibiotic therapy for extracorporeal membrane oxygenation (ECMO) patients remains a pharmacological challenge. The objective of this study was to observe the plasma concentrations of commonly used antibiotics in intensive care for patients treated with extracorporeal membrane oxygenation. PATIENTS AND METHODS: The PHARMECMO study was a pilot, prospective study, conducted in a cardiac surgery intensive care unit. Every adult patient under ECMO support, with known or suspected sepsis and receiving antibiotic therapy, was eligible for inclusion. Plasma concentrations of antibiotics were determined by a combination of liquid chromatography and mass spectrometry. RESULTS: Forty-four eligible patients were enrolled for 68 inclusions on a twelve-month period. For the association piperacillin-tazobactam (n=19), 68.7% of CT50 and 93.7% of Cmin reached the pharmacokinetic goals defined (64 mg.L-1 for CT50 and 16 mg.L-1 for Cmin). For cefotaxime (n=12), the pharmacokinetic goals (4 mg.L-1 for CT50 and 1 mg.L-1 for Cmin) were achieved in 100% of the cases for CT50 and in 81.8% of the cases for Cmin. Regarding imipenem (n=10), the pharmacokinetic goals were 16 mg.L-1 for CT50 and 4 mg.L-1 for Cmin. Only one CT50 was above 16 mg.L-1. For Cmin, 60% of the doses did not reach the target concentration. In our 10 patients, only one patient was considered as reaching the pharmacokinetic goals. Finally, for amikacin (n=6), four Cmax (66.7%) were infra-therapeutics for a target between 60 and 80 mg.L-1. CONCLUSION: These preliminary results suggest that therapeutic drug monitoring could optimise the achievement of pharmacokinetic objectives associated with an effective antibiotic therapy. For most patients, the recommended doses of imipenem and amikacin did not achieve the pK targets.

Cefiderocol versus imipenem-cilastatin for the treatment of complicated urinary tract infections caused by Gram-negative uropathogens: a phase 2, randomised, double-blind, non-inferiority trial.

BACKGROUND: Carbapenem-resistant Gram-negative bacteria represent the highest priority for addressing global antibiotic resistance. Cefiderocol (S-649266), a new siderophore cephalosporin, has broad activity against Enterobacteriaceae and non-fermenting bacteria, such as Pseudomonas aeruginosa and Acinetobacter baumannii, including carbapenem-resistant strains. We assessed the efficacy and safety of cefiderocol versus imipenem-cilastatin for the treatment of complicated urinary tract infection in patients at risk of multidrug-resistant Gram-negative infections. METHODS: We did a phase 2, multicentre, double-blind, parallel-group non-inferiority trial at 67 hospitals in 15 countries. Adults (≥18 years) admitted to hospital with a clinical diagnosis of complicated urinary tract infection with or without pyelonephritis or those with acute uncomplicated pyelonephritis were randomly assigned (2:1) by an interactive web or voice response system to receive 1 h intravenous infusions of cefiderocol (2 g) or imipenem-cilastatin (1 g each) three times daily, every 8 h for 7-14 days. Patients were excluded if they had a baseline urine culture with more than two uropathogens, a fungal urinary tract infection, or pathogens known to be carbapenem resistant. The primary endpoint was the composite of clinical and microbiological outcomes at test of cure (ie, 7 days after treatment cessation), which was used to establish non-inferiority (15% and 20% margins) of cefiderocol versus imipenem-cilastatin. The primary efficacy analysis was done on a modified intention-to-treat population, which included all randomly assigned individuals who received at least one dose of study drug and had a qualifying Gram-negative uropathogen (≥1 × 105 colony-forming units [CFU]/mL). Safety was assessed in all randomly assigned individuals who received at least one dose of study drug, according to the treatment they received. This study is registered with ClinicalTrials.gov, number NCT02321800. FINDINGS: Between Feb 5, 2015, and Aug 16, 2016, 452 patients were randomly assigned to cefiderocol (n=303) or imipenem-cilastatin (n=149), of whom 448 patients (n=300 in the cefiderocol group; n=148 in the imipenem-cilastatin group) received treatment. 371 patients (n=252 patients in the cefiderocol group; n=119 patients in the imipenem-cilastatin group) had qualifying Gram-negative uropathogen (≥1 × 105 CFU/mL) and were included in the primary efficacy analysis. At test of cure, the primary efficacy endpoint was achieved by 183 (73%) of 252 patients in the cefiderocol group and 65 (55%) of 119 patients in the imipenem-cilastatin group, with an adjusted treatment difference of 18·58% (95% CI 8·23-28·92; p=0·0004), establishing the non-inferiority of cefiderocol. Cefiderocol was well tolerated. Adverse events occurred in 122 (41%) of 300 patients in the cefiderocol group and 76 (51%) of 148 patients in the imipenem-cilastatin group, with gastrointestinal disorders (ie, diarrhoea, constipation, nausea, vomiting, and abdominal pain) the most common adverse events for both treatment groups (35 [12%] patients in the cefiderocol group and 27 [18%] patients in the imipenem-cilastatin group). INTERPRETATION: Intravenous infusion of cefiderocol (2 g) three times daily was non-inferior compared with imipenem-cilastatin (1 g each) for the treatment of complicated urinary tract infection in people with multidrug-resistant Gram-negative infections. The results of this study will provide the basis for submission of a New Drug Application to the US Food and Drug Administration. Clinical trials of hospital-acquired pneumonia and carbapenem-resistant infections are ongoing. FUNDING: Shionogi & Co Ltd, Shionogi Inc.