Assessment of the mass balance recovery and metabolite profile of avibactam in humans and in vitro drug-drug interaction potential

Pharmacokinetic parameters of CAZ-AVI in the normal lung and in models of pneumonia: lessons for treatment optimization in critical care

The spread of multidrug-resistant Gram-negative bacterial infections is a significant issue for worldwide public health. Gram-negative organisms regularly develop resistance to antibiotics, especially to β-lactam antimicrobials, which can drastically restrict the number of therapies. A third-generation cephalosporin and the non-β-lactam β-lactamase inhibitor avibactam, which exhibits broad-spectrum β-lactamase inhibition in vitro, are combined to form ceftazidime-avibactam (CAZ-AVI). In this narrative review, we summarize data on pharmacokinetic (PK) parameters for CAZ-AVI in both animal and human models of pneumonia, as well as in healthy individuals. We assessed current literature performing an extensive search of the literature, using as search words 'CAZ-AVI', 'pharmacokinetics', 'pneumonia', 'lung', and 'epithelial lining fluid'. Overall, lung exposure studies of CAZ-AVI revealed that the epithelial lining fluid penetration ranges between 30% and 35% of plasma concentration. Despite the fair lung penetration of CAZ-AVI, this antimicrobial agent has a pivotal role in managing patients with multi-drug resistant Gram-negative pneumonia, however further studies are needed to better assess its PK profile.

An Investigation in the Comparability of the Exposure and Recommended Dose of Selected Pfizer Drugs in East Asian Countries: Is Mutual Usage of Clinical Data Among East Asian Countries Feasible?

The current regulatory path for new drug registration in East Asian countries has led to significant delay of the new medicines in these countries. A unified regulatory path and allowance of mutual usage of clinical data in East Asian countries would lead to cost saving in drug development and expedite the new drug registration in these countries. The objectives of the present analysis are to compare the approval dates of a selection of products developed by Pfizer in the United States and East Asian countries (China, Japan, Korea) and compare the pharmacokinetics and recommended doses of these products in East Asian countries. Eighteen products (20 drugs, 2 products with 2 combination drugs) with exposure data available in at least 2 of the 3 East Asian countries across different therapeutic areas were included in the analyses. The results showed that most products had delayed approval in East Asian countries (up to 8 years) after US or EU approval. No distinct differences were observed in the drug exposure and recommended doses for the selected products in East Asian countries. These results together with literature data of genetic similarity of the East Asian populations support the mutual usage of the clinical data in the East Asian countries for expedited regulatory submission and approval.

Dose selection for aztreonam-avibactam, including adjustments for renal impairment, for Phase IIa and Phase III evaluation

PURPOSE

A series of iterative population pharmacokinetic (PK) modeling and probability of target attainment (PTA) analyses based on emerging data supported dose selection for aztreonam-avibactam, an investigational combination antibiotic for serious Gram-negative bacterial infections.

METHODS

Two iterations of PK models built from avibactam data in infected patients and aztreonam data in healthy subjects with "patient-like" assumptions were used in joint PTA analyses (primary target: aztreonam 60% fT > 8 mg/L, avibactam 50% fT > 2.5 mg/L) exploring patient variability, infusion durations, and adjustments for moderate (estimated creatinine clearance [CrCL] > 30 to ≤ 50 mL/min) and severe renal impairment (> 15 to ≤ 30 mL/min). Achievement of > 90% joint PTA and the impact of differential renal clearance were considerations in dose selection.

RESULTS

Iteration 1 simulations for Phase I/IIa dose selection/modification demonstrated that 3-h and continuous infusions provide comparable PTA; avibactam dose drives joint PTA within clinically relevant exposure targets; and loading doses support more rapid joint target attainment. An aztreonam/avibactam 500/137 mg 30-min loading dose and 1500/410 mg 3-h maintenance infusions q6h were selected for further evaluation. Iteration 2 simulations using expanded PK models supported an alteration to the regimen (500/167 mg loading; 1500/500 mg q6h maintenance 3-h infusions for CrCL > 50 mL/min) and selection of doses for renal impairment for Phase IIa/III clinical studies.

CONCLUSION

A loading dose plus 3-h maintenance infusions of aztreonam-avibactam in a 3:1 fixed ratio q6h optimizes joint PTA. These analyses supported dose selection for the aztreonam-avibactam Phase III clinical program.

CLINICAL TRIAL REGISTRATION

NCT01689207; NCT02655419; NCT03329092; NCT03580044.

Ceftazidime-avibactam induced renal disorders: past and present

With the increasing prevalence of multidrug-resistant Gram-negative bacterial pathogens worldwide, antimicrobial resistance has become a significant public health concern. Ceftazidime-avibactam (CAZ-AVI) exhibited excellent in vitro activity against many carbapenemase-producing pathogens, and was widely used for the treatment of various complicated infections. CAZ-AVI is well tolerated across all dosing regimens, and its associated acute kidney injury (AKI) in phase II/III clinical trials is rare. However, recent real-world studies have demonstrated that CAZ-AVI associated AKI was more frequent in real-world than in phase II and III clinical trials, particularly in patients receiving concomitant nephrotoxic agents, with critically ill patients being at a higher risk. Herein, we reviewed the safety data related to renal impairment of CAZ-AVI, and discussed its pharmacokinetic/pharmacodynamic targets and dosage adjustment in patients with impaired renal function. This review aimed to emphasize the importance for healthcare professionals to be aware of this adverse event of CAZ-AVI and provide practical insights into the dosage optimization in critically ill patients with renal dysfunction.

New Antibiotics for the Treatment of Nosocomial Central Nervous System Infections

Nosocomial central nervous system (CNS) infections with carbapenem- and colistin-resistant Gram-negative and vancomycin-resistant Gram-positive bacteria are an increasing therapeutic challenge. Here, we review pharmacokinetic and pharmacodynamic data and clinical experiences with new antibiotics administered intravenously for the treatment of CNS infections by multi-resistant bacteria. Cefiderocol, a new siderophore extended-spectrum cephalosporin, pharmacokinetically behaves similar to established cephalosporins and at high doses will probably be a valuable addition in our therapeutic armamentarium for CNS infections. The new glycopeptides dalbavancin, telavancin, and oritavancin are highly bound to plasma proteins. Although effective in animal models of meningitis, it is unlikely that they reach effective cerebrospinal fluid (CSF) concentrations after intravenous administration alone. The β-lactam/β-lactamase inhibitor combinations have the principal problem that both compounds must achieve adequate CSF concentrations. In the commercially available combinations, the dose of the β-lactamase inhibitor tends to be too low to achieve adequate CSF concentrations. The oxazolidinone tedizolid has a broader spectrum but a less suitable pharmacokinetic profile than linezolid. The halogenated tetracycline eravacycline does not reach CSF concentrations sufficient to treat colistin-resistant Gram-negative bacteria with usual intravenous dosing. Generally, treatment of CNS infections should be intravenous, whenever possible, to avoid adverse effects of intraventricular therapy (IVT). An additional IVT can overcome the limited penetration of many new antibiotics into CSF. It should be considered for patients in which the CNS infection responds poorly to systemic antimicrobial therapy alone.

Therapeutic drug monitoring of ceftazidime/avibactam: why one leg is not enough to run

BACKGROUND

Therapeutic drug monitoring (TDM) is becoming an increasingly recommended approach for assessing optimal pharmacokinetic/pharmacodynamic (PK/PD) target attainment of ceftazidime/avibactam. Some authors hypothesized that the PK/PD target attainment of ceftazidime/avibactam could be assessed by means of the TDM of solely ceftazidime, since avibactam concentrations might be extrapolated based on the fixed 4:1 ceftazidime-to-avibactam ratio present in the vial. The reliability of this hypothesis could be called into question if a wide interindividual variability in the ceftazidime-to-avibactam ratio would exist among patients. This study aimed to assess the distribution of the individual ceftazidime-to-avibactam ratios in relation to renal function in a cohort of adult patients who were treated with continuous infusion ceftazidime/avibactam and underwent TDM of both ceftazidime and avibactam.

METHODS

Individual ceftazidime-to-avibactam ratio was calculated at each TDM assessment. Receiving operating characteristics (ROC) curve analysis was performed for testing the potential impact of renal function on ceftazidime-to-avibactam ratio variability.

RESULTS

A total of 188 TDM assessments were collected from 107 patients. The ceftazidime-to-avibactam ratios ranged from 1.29:1 to 13.46:1. Seventy-seven out of 188 ceftazidime-to-avibactam ratios (41.0%) were >5:1, and 36 (19.1%) were >6:1. Patients without renal dysfunction had significantly higher proportions of ceftazidime-to-avibactam ratio >5:1 (59.3% versus 23.8%; P < 0.001) and >6:1 (32.1% versus 6.3%; P < 0.001) compared with those with mild-to-severe renal dysfunction.

CONCLUSIONS

The findings may strengthen the contention that for properly assessing the PK/PD target attainment of ceftazidime/avibactam, both ceftazidime and avibactam concentrations should be measured, given the unpredictability of the ceftazidime-to-avibactam ratio occurring among patients.

Clinical Efficacy and Safety Evaluation of Ceftazidime-Avibactam in the Treatment of Klebsiella pneumoniae Infection: A Retrospective Analysis from a Hospital in China

Background

Ceftazidime-avibactam (CAZ-AVI) is a new cephalosporin/β-lactamase inhibitor combination that received clinical approval in China in 2019. This study aims to investigate the efficacy and safety of CAZ-AVI in the treatment of Klebsiella pneumoniae (KP) infection in a hospital, and differences in efficacy among various infection sites and between monotherapy and combination therapy, providing valuable insights for its further application.

Methods

Patients who used CAZ-AVI between January 2019 and April 2023 were identified through the hospital information system. Demographic information, details of the infection site, KP strain's drug sensitivity report, treatment duration, combination therapies, adverse drug reactions (ADR), and 28-day survival were recorded. Clinical and microbiological efficacies were analyzed using SPSS 23.0 software to compare different infection sites and combination therapies.

Results

The overall effective clinical response (CR) rate of CAZ-AVI against KP infection was 62.13%, with a favorable microbial response (MR) rate was 65.68% and a 28-day survival rate was 63.91%. No significant difference occurred in effective CR and 28-day survival rate among different infection sites (P = 0.709 and 0.862, respectively). The favorable MR rate for abdominal infections was slightly lower than that for other sites of infection (P = 0.021). No significant differences in effective CR, favorable MR, and 28-day survival between monotherapy and combination therapy were present (P values were 0.649, 0.123, and 0.280, respectively). The incidence of ADR was 1.78%, including increased creatinine, elevated transaminase, hematuria, and thrombocytopenia.

Conclusion

CAZ-AVI demonstrates good clinical efficacy and safety in the treatment of KP infections. The clinical efficacy of CAZ-AVI was similar across different infection sites, and combination therapy did not show an advantage over monotherapy. Further studies are warranted. It should be noted that CAZ-AVI may induce thrombocytopenia and hematuria.

Population Pharmacokinetic Modeling and Probability of Pharmacodynamic Target Attainment for Ceftazidime-Avibactam in Pediatric Patients Aged 3 Months and Older

Increasing prevalence of infections caused by antimicrobial-resistant gram-negative bacteria represents a global health crisis, and while several novel therapies that target various aspects of antimicrobial resistance have been introduced in recent years, few are currently approved for children. Ceftazidime-avibactam is a novel β-lactam β-lactamase inhibitor combination approved for adults and children 3 months and older with complicated intra-abdominal infection, and complicated urinary tract infection or hospital-acquired ventilator-associated pneumonia (adults only in the United States) caused by susceptible gram-negative bacteria. Extensive population pharmacokinetic (PK) data sets for ceftazidime and avibactam obtained during the adult clinical development program were used to iteratively select, modify, and validate the approved adult dosage regimen (2,000-500 mg by 2-hour intravenous (IV) infusion every 8 hours (q8h), with adjustments for renal function). Following the completion of one phase I (NCT01893346) and two phase II ceftazidime-avibactam studies (NCT02475733 and NCT02497781) in children, adult PK data sets were updated with pediatric PK data. This paper describes the development of updated combined adult and pediatric population PK models and their application in characterizing the population PK of ceftazidime and avibactam in children, and in dose selection for further pediatric evaluation. The updated models supported the approval of ceftazidime-avibactam pediatric dosage regimens (all by 2-hour IV infusion) of 50-12.5 mg/kg (maximum 2,000-500 mg) q8h for those ≥6 months to 18 years old, and 40-10 mg/kg q8h for those ≥3 to 6 months old with creatinine clearance > 50 mL/min/1.73 m2 .

Antimicrobial Treatment Options for Difficult-to-Treat Resistant Gram-Negative Bacteria Causing Cystitis, Pyelonephritis, and Prostatitis: A Narrative Review

Urinary tract infections, including cystitis, acute pyelonephritis, and prostatitis, are among the most common diagnoses prompting antibiotic prescribing. The rise in antimicrobial resistance over the past decades has led to the increasing challenge of urinary tract infections because of multidrug-resistant and "difficult-to-treat resistance" among Gram-negative bacteria. Recent advances in pharmacotherapy and medical microbiology are modernizing how these urinary tract infections are treated. Advances in pharmacotherapy have included not only the development and approval of novel antibiotics, such as ceftazidime/avibactam, meropenem/vaborbactam, imipenem/relebactam, ceftolozane/tazobactam, cefiderocol, plazomicin, and glycylcyclines, but also the re-examination of the potential role of legacy antibiotics, including older aminoglycosides and tetracyclines. Recent advances in medical microbiology allow phenotypic and molecular mechanism of resistance testing, and thus antibiotic prescribing can be tailored to the mechanism of resistance in the infecting pathogen. Here, we provide a narrative review on the clinical and pre-clinical studies of drugs that can be used for difficult-to-treat resistant Gram-negative bacteria, with a particular focus on data relevant to the urinary tract. We also offer a pragmatic framework for antibiotic selection when encountering urinary tract infections due to difficult-to-treat resistant Gram-negative bacteria based on the organism and its mechanism of resistance.

Safety Profile of Ceftazidime-Avibactam: Pooled Data from the Adult Phase II and Phase III Clinical Trial Programme

INTRODUCTION

Ceftazidime-avibactam combines the established anti-pseudomonal cephalosporin, ceftazidime, with the novel non-β-lactam β-lactamase inhibitor, avibactam.

OBJECTIVES

The aim of this study was to evaluate the safety of ceftazidime-avibactam in adults using pooled data from two phase II (NCT00690378, NCT00752219) and five phase III (NCT01499290, NCT01726023, NCT01644643, NCT01808093 and NCT01595438/NCT01599806) clinical studies.

METHODS

Safety data from seven multicentre, randomised, active-comparator studies were pooled by study group at the patient level for descriptive analyses, comprising patients with complicated urinary tract infection (cUTI), including pyelonephritis, complicated intra-abdominal infection (cIAI), or nosocomial pneumonia (NP), including ventilator-associated pneumonia (VAP), treated with ceftazidime-avibactam ± metronidazole or comparator.

RESULTS

In total, 4050 patients (ceftazidime-avibactam ± metronidazole, n = 2024; comparator, n = 2026) were included in the pooled analysis. Adverse events (AEs) up to the last study visit occurred in 996 (49.2%) and 965 (47.6%) patients treated with ceftazidime-avibactam ± metronidazole and comparator, respectively. The most common AEs across treatment groups were diarrhoea, nausea, headache, vomiting and pyrexia. There were few discontinuations due to AEs (2.5% and 1.7% for ceftazidime-avibactam ± metronidazole and comparators, respectively). Overall rates of serious AEs were 8.7% for ceftazidime-avibactam ± metronidazole and 7.2% for comparators; respective rates of AEs with an outcome of death were 2.0% and 1.8%. AEs considered causally related to the study drug or procedures occurred in 10.7% and 9.6% of patients treated with ceftazidime-avibactam ± metronidazole and comparators; the most common drug-related AEs in both groups were diarrhoea, headache, nausea and increased alanine aminotransferase. No impact to the safety profile of ceftazidime-avibactam ± metronidazole was found with regard to intrinsic factors, such as age or renal function at baseline, or extrinsic factors, such as geographical origin. Potentially clinically significant changes in laboratory parameters were infrequent with no trends or safety concerns identified.

CONCLUSION

The observed safety profile of ceftazidime-avibactam across infection types is consistent with the established safety profile of ceftazidime monotherapy and no new safety findings were identified. This analysis supports the use of ceftazidime-avibactam as a treatment option in adults with cUTI, cIAI and NP, including VAP.

Pharmacokinetics of Non-β-Lactam β-Lactamase Inhibitors

The growing emergence of drug-resistant bacterial strains is an issue to treat severe infections, and many efforts have identified new pharmacological agents. The inhibitors of β-lactamases (BLI) have gained a prominent role in the safeguard of beta-lactams. In the last years, new β-lactam-BLI combinations have been registered or are still under clinical evaluation, demonstrating their effectiveness to treat complicated infections. It is also noteworthy that the pharmacokinetics of BLIs partly matches that of β-lactams companions, meaning that some clinical situations, as well as renal impairment and renal replacement therapies, may alter the disposition of both drugs. Common pharmacokinetic characteristics, linear pharmacokinetics across a wide range of doses, and known pharmacokinetic/pharmacodynamic parameters may guide modifications of dosing regimens for both β-lactams and BLIs. However, comorbidities (i.e., burns, diabetes, cancer) and severe changes in individual pathological conditions (i.e., acute renal impairment, sepsis) could make dose adaptation difficult, because the impact of those factors on BLI pharmacokinetics is partly known. Therapeutic drug monitoring protocols may overcome those issues and offer strategies to personalize drug doses in the intensive care setting. Further prospective clinical trials are warranted to improve the use of BLIs and their β-lactam companions in severe and complicated infections.

Using Therapeutic Drug Monitoring to Treat KPC-Producing Klebsiella pneumoniae Central Nervous System Infection With Ceftazidime/Avibactam

This report describes the treatment of Klebsiella pneumoniae carbapenemase (KPC)–3–producing multidrug-resistant K. pneumoniae with ceftazidime/avibactam (CAZ-AVI) in a patient who developed postneurosurgical meningitis and bacteremia. Therapeutic drug monitoring of cerebrospinal fluid and blood samples demonstrated CAZ-AVI concentration levels 20-fold greater than the minimum inhibitory concentration in the first 60 minutes postinfusion, providing evidence for the utility of CAZ-AVI in treating KPC–Klebsiella pneumoniae central nervous system infections.

Considerations in the Selection of Renal Dosage Adjustments for Patients with Serious Infections and Lessons Learned from the Development of Ceftazidime-Avibactam

An extensive clinical development program (comprising two phase 2 and five phase 3 trials) has demonstrated the efficacy and safety of ceftazidime-avibactam in the treatment of adults with complicated intra-abdominal infection (cIAI), complicated urinary tract infection (cUTI), and hospital-acquired pneumonia (HAP), including ventilator-associated pneumonia (VAP). During the phase 3 clinical program, updated population pharmacokinetic (PK) modeling and Monte Carlo simulations using clinical PK data supported modified ceftazidime-avibactam dosage adjustments for patients with moderate or severe renal impairment (comprising a 50% increase in total daily dose compared with the original dosage adjustments) to reduce the risk of subtherapeutic drug exposures in the event of rapidly improving renal function. The modified dosage adjustments were included in the ceftazidime-avibactam labeling information at the time of initial approval and were subsequently evaluated in the final phase 3 trial (in patients with HAP, including VAP), providing supportive data for the approved U.S. and European ceftazidime-avibactam dosage regimens across renal function categories. This review describes the analyses supporting the ceftazidime-avibactam dosage adjustments for renal impairment and discusses the wider implications and benefits of using modeling and simulation to support dosage regimen optimization based on emerging clinical evidence.

Dose Selection and Validation for Ceftazidime-Avibactam in Adults with Complicated Intra-abdominal Infections, Complicated Urinary Tract Infections, and Nosocomial Pneumonia

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.

Quantitative Assessment of the Effect of Chronic Kidney Disease on the Nonrenal Clearance of 10 Drugs After Intravenous Administration

The investigation identified 10 publications that reported the individual values of total clearance (CL), renal clearance (CLr), nonrenal clearance (CLnr), and the glomerular filtration rate (GFR), in subjects with varying renal functions. We used these data to estimate extent and prevalence of changes in CLnr in chronic kidney disease (CKD) by examining the relationship between clearances and renal function. The investigation was restricted to drugs given intravenously and eliminated by mixed renal and nonrenal pathways. Six drugs showed a significant reduction of CLnr of 61% to 63% in subjects with severe renal impairment, suggesting that the decline of CLnr in advanced CKD can be clinically relevant and may not be uncommon. The decline of CLnr in CKD for these 6 drugs is linearly correlated with the decline of CLr. With 4 of the drugs studied, a significant reduction of CLnr in CKD was not seen. Renal clearance is a more reliable measure of renal function than GFR assessed by creatinine clearance. Chronic kidney disease affects the elimination more than the distribution of the 10 drugs.

Ceftazidime-Avibactam Population Pharmacokinetic Modeling and Pharmacodynamic Target Attainment Across Adult Indications and Patient Subgroups

Ceftazidime‐avibactam is a novel β‐lactam/β‐lactamase inhibitor combination for the treatment of serious infections caused by resistant gram‐negative pathogens. Population pharmacokinetic (PopPK) models were built to incorporate pharmacokinetic (PK) data from five phase III trials in patients with complicated intra‐abdominal infection (cIAI), complicated urinary tract infection (cUTI), or nosocomial (including ventilator‐associated) pneumonia. Ceftazidime and avibactam pharmacokinetics were well‐described by two‐compartment disposition models, with creatinine clearance (CrCL) the key covariate determining clearance variability. Steady‐state ceftazidime and avibactam exposure for most patient subgroups differed by ≤ 20% vs. healthy volunteers. Probability of PK/pharmacodynamic (PD) target attainment (free plasma ceftazidime > 8 mg/L and avibactam > 1 mg/L for ≥ 50% of dosing interval) was ≥ 94.9% in simulations for all patient subgroups, including indication and renal function categories. No exposure‐microbiological response relationship was identified because target exposures were achieved in almost all patients. These modeling results support the approved ceftazidime‐avibactam dosage regimens (2000‐500 mg every 8 hours, adjusted for CrCL ≤ 50 mL/min).

Microdialysis Study of Aztreonam-Avibactam Distribution in Peritoneal Fluid and Muscle of Rats with or without Experimental Peritonitis

The purpose of this study was to investigate aztreonam (ATM) and avibactam (AVI) distribution in intraperitoneal fluid and muscle interstitial fluid by microdialysis in rats, with or without peritonitis, and to compare the unbound concentrations in tissue with the unbound concentrations in blood. Microdialysis probes were inserted into the jugular veins, hind leg muscles, and peritoneal cavities of control rats (n = 5) and rats with intra-abdominal sepsis (n = 9) induced by cecal ligation and punctures. ATM and AVI probe recoveries in each medium were determined for both molecules in each rat by retrodialysis by drug. ATM-AVI combination was administered as an intravenous bolus at a dose of 100-25 mg · kg^-1 Microdialysis samples were collected over 120 min, and ATM-AVI concentrations were determined by liquid chromatography-tandem mass spectrometry. Noncompartmental pharmacokinetic analysis was conducted and nonparametric tests were used for statistical comparisons between groups (infected versus control) and medium. ATM and AVI distribution in intraperitoneal fluid and muscle was rapid and complete both in control rats and in rats with peritonitis, and the concentration profiles in blood, intraperitoneal fluid, and muscle were virtually superimposed, in control and infected animals, both for ATM and AVI. No statistically significant difference was observed between unbound tissue extracellular fluid and systemic areas under the curve for both molecules in control and infected animals. In the present study, intraperitoneal infection induced by cecal ligation and puncture had no apparent effect on ATM and AVI pharmacokinetics in rats.

Pharmacokinetic drug evaluation of avibactam + ceftazidime for the treatment of hospital-acquired pneumonia

INTRODUCTION

Ceftazidime-avibactam (CAZ-AVI) is a combination of a third-generation cephalosporin and a non-β-lactam, β-lactamase inhibitor, recently approved for urinary tract infections and complicated abdominal infections. Moreover, it represents a treatment option for patients with hospital acquired pneumonia (HAP), especially when caused by multidrug-resistant (MDR) bacteria. Areas covered: The review focuses on the pharmacokinetics (PK) of CAZ-AVI in HAP and on preclinical and clinical studies evaluating PK/pharmacodynamics (PD) in this field. Expert opinion: In vitro and in vivo data about PK/PD of CAZ-AVI confirm that penetration of CAZ-AVI in the epithelial lining fluid (ELF) represents approximately 30% of the plasma concentrations. Clinical studies documented that CAZ-AVI 2000 mg/500 mg every 8 h is the optimal dose regimen to achieve the PK/PD target attainment in patients with HAP. Thus, CAZ-AVI could represent an option both to treat HAP caused by Gram-negative bacilli (GNB) displaying resistance to most of the antibiotics and to reduce the use of carbapenems, limiting the onset of resistance profiles among GNB. Additional information about specific patients populations, such as critically-ill subjects or pediatric patients, are needed for a more individualized use of CAZ-AVI.

Pharmacological aspects and spectrum of action of ceftazidime-avibactam: a systematic review

PURPOSE

Ceftazidime-avibactam is an antimicrobial association active against several Enterobacteriaceae species, including those resistant to carbapenem. Considering the importance of this drug in the current panorama of multidrug-resistant bacteria, we performed a systematic review about ceftazidime-avibactam with emphasis on clinical and pharmacological published data.

METHODS

A systematic search of the medical literature was performed. The databases searched included MEDLINE, EMBASE and Web of Science (until September 2017). The search terms used were 'avibactam', 'NXL104' and 'AVE1330A'. Bibliographies from those studies were also reviewed. Ceftazidime was not included as a search term, once relevant studies about avibactam in association with other drugs could be excluded. Only articles in English were selected. No statistical analysis or quality validation was included in this review.

RESULTS

A total of 151 manuscripts were included. Ceftazidime-avibactam has limited action against anaerobic bacteria. Avibactam is a potent inhibitor of class A, class C, and some class D enzymes, which includes KPC-2. The best pharmacodynamic profile of ceftazidime-avibactam is ƒT > MIC, validated in an animal model of soft tissue infection. Three clinical trials showed the efficacy of ceftazidime-avibactam in patients with intra-abdominal and urinary infections. Ceftazidime-avibactam has been evaluated versus meropenem/doripenem in hospitalized adults with nosocomial pneumonia, neutropenic patients and pediatric patients.

CONCLUSION

Ceftazidime-avibactam has a favorable pharmacokinetic profile for severe infections and highly active against carbapenemases of KPC-2 type.

Renal Drug Transporters and Drug Interactions

Transporters in proximal renal tubules contribute to the disposition of numerous drugs. Furthermore, the molecular mechanisms of tubular secretion have been progressively elucidated during the past decades. Organic anions tend to be secreted by the transport proteins OAT1, OAT3 and OATP4C1 on the basolateral side of tubular cells, and multidrug resistance protein (MRP) 2, MRP4, OATP1A2 and breast cancer resistance protein (BCRP) on the apical side. Organic cations are secreted by organic cation transporter (OCT) 2 on the basolateral side, and multidrug and toxic compound extrusion (MATE) proteins MATE1, MATE2/2-K, P-glycoprotein, organic cation and carnitine transporter (OCTN) 1 and OCTN2 on the apical side. Significant drug-drug interactions (DDIs) may affect any of these transporters, altering the clearance and, consequently, the efficacy and/or toxicity of substrate drugs. Interactions at the level of basolateral transporters typically decrease the clearance of the victim drug, causing higher systemic exposure. Interactions at the apical level can also lower drug clearance, but may be associated with higher renal toxicity, due to intracellular accumulation. Whereas the importance of glomerular filtration in drug disposition is largely appreciated among clinicians, DDIs involving renal transporters are less well recognized. This review summarizes current knowledge on the roles, quantitative importance and clinical relevance of these transporters in drug therapy. It proposes an approach based on substrate-inhibitor associations for predicting potential tubular-based DDIs and preventing their adverse consequences. We provide a comprehensive list of known drug interactions with renally-expressed transporters. While many of these interactions have limited clinical consequences, some involving high-risk drugs (e.g. methotrexate) definitely deserve the attention of prescribers.

Pharmacodynamic and pharmacokinetic considerations in the treatment of critically Ill patients infected with carbapenem-resistant Enterobacteriaceae

Carbapenem-Resistant Enterobacteriaceae (CRE) are an emerging healthcare crisis. Infections due to CRE are associated with high morbidity and mortality, especially in critically ill patients. Due to the multi-drug resistant nature of these infections only limited treatment options are available. Antimicrobials that have been described for the treatment of CRE infections include carbapenems, polymyxins, fosfomycin, tigecycline, aminoglycosides, and ceftazidime-avibactam. Given the limited treatment options it is imperative the pharmacokinetic and pharmacodynamics (PK-PD) characteristics of these agents are considered to optimize treatment regimens. This review will focus on the PK-PD challenges of the current treatment options for CRE infections.

Ceftazidime-avibactam for the treatment of complicated intra-abdominal infections

INTRODUCTION

The treatment of complicated intra-abdominal infections (cIAI) is increasingly challenging due to increased resistance of Gram-negative organisms. These multidrug resistant organisms lead to an increase in morbidity and mortality. This has led to renewed interest in use of older β-lactam antibiotics in combination with newer β-lactamase inhibitors. Ceftazidime-avibactam is one of the newest such combination antibiotics, which has been released for treatment of complicated intra-abdominal infections in combination with metronidazole. Areas covered: In this drug evaluation manuscript cIAI along with the chemistry, pharmacodynamics, pharmacokinetics, metabolism and clinical study results of ceftazidime-avibactam are reviewed. Expert opinion: The role of ceftazidime-avibactam in combination with metronidazole in the treatment of cIAI is still to be defined. Patients with cIAI known to be infected with Klebsiella pneumoniae carbapenemase-producing Enterobacteriaceae would be clear candidates for treatment with this agent, as would patients infected with more common types of extended-spectrum β-lactamase producing Gram-negative pathogens if a carbapenem alternative were desired. At present, it is difficult to establish a clear group of patients with cIAI for whom initial empiric therapy with this agent would be warranted.

Phase 1 Study Assessing the Pharmacokinetic Profile and Safety of Avibactam in Patients With Renal Impairment

Avibactam is a non-β-lactam β-lactamase inhibitor intended for use as a fixed-dose combination with ceftazidime for the treatment of certain serious Gram-negative infections. As avibactam is primarily excreted unchanged in the urine, renal impairment may affect its pharmacokinetics. This phase 1 study investigated the effect of renal impairment and hemodialysis on avibactam pharmacokinetics and safety. Healthy controls and subjects with increasing degrees of renal impairment received a single 30-minute intravenous (IV) infusion of avibactam (100 mg). Anuric subjects requiring hemodialysis received the same infusion pre- and posthemodialysis, separated by a 7- to 14-day washout. Blood and urine samples were collected, and pharmacokinetics were analyzed using noncompartmental methods. The relationships between avibactam total plasma clearance (CL) or renal clearance (CL_R ) and creatinine clearance (CrCL) were evaluated by linear correlation analysis. Safety was also monitored. Increasing severity of renal impairment was associated with decreasing CL and CL_R and increasing exposure and terminal half-life (t_1/2 ). Avibactam CL and CL_R demonstrated an approximately linear relationship with CrCL comparable to that previously observed for ceftazidime. In patients requiring hemodialysis, >50% of the administered avibactam was removed during a 4-hour hemodialysis session, demonstrating that avibactam should be administered after hemodialysis. No new safety findings were reported. To conclude, avibactam dose adjustment is warranted in patients with renal impairment based on the severity of impairment. Because the slope of the linear relationship between avibactam total plasma CL and CrCL is similar to that of ceftazidime, renal impairment dose adjustments should maintain the currently advised 4:1 ratio of ceftazidime:avibactam.

Predictive Performance of Physiologically Based Pharmacokinetic and Population Pharmacokinetic Modeling of Renally Cleared Drugs in Children

Predictive performance of physiologically based pharmacokinetic (PBPK) and population pharmacokinetic (PopPK) models of drugs predominantly eliminated through kidney in the pediatric population was evaluated. After optimization using adult clinical data, the verified PBPK models can predict 33 of 34 drug clearance within twofold of the observed values in children 1 month and older. More specifically, 10 of 11 of predicted clearance values were within 1.5‐fold of those observed in children between 1 month and 2 years old. The PopPK approach also predicted 19 of 21 drug clearance within twofold of the observed values in children. In summary, our analysis demonstrated both PBPK and PopPK adult models, after verification with additional adult pharmacokinetic (PK) studies and incorporation of known ontogeny of renal filtration, could be applied for dosing regimen recommendation in children 1 month and older for renally eliminated drugs in a first‐in‐pediatric study.

Ceftazidime/avibactam: a novel cephalosporin/nonbeta-lactam beta-lactamase inhibitor for the treatment of complicated urinary tract infections and complicated intra-abdominal infections

There has been greater interest in developing additional antimicrobial agents due to the increasing health care costs and resistance resulting from bacterial pathogens to currently available treatment options. Gram-negative organisms including Enterobacteriaceae and Pseudomonas aeruginosa are some of the most concerning threats due to their resistance mechanisms: extended-spectrum beta-lactamase production and Klebsiella pneumoniae carbapenemase enzymes. Ceftazidime is a third-generation broad-spectrum cephalosporin with activity against P. aeruginosa and avibactam is a novel nonbeta-lactam beta-lactamase inhibitor. Avycaz(®), the trade name for this new combination antibiotic, restores the activity of ceftazidime against some of the previously resistant pathogens. Avycaz was approved in 2015 for the treatment of complicated urinary tract infections, including pyelonephritis, and complicated intra-abdominal infections with the addition of metronidazole in patients with little to no other treatment options. This review article assesses the clinical trials and data that led to the approval of this antibiotic, in addition to its spectrum of activity and limitations.

Safety and pharmacokinetics of single and multiple ascending doses of avibactam alone and in combination with ceftazidime in healthy male volunteers: results of two randomized, placebo-controlled studies

BACKGROUND AND OBJECTIVE

Avibactam is a novel non-β-lactam β-lactamase inhibitor effective against Ambler class A, C and some class D β-lactamases that is currently in clinical development in combination with ceftazidime for the treatment of serious Gram-negative infections. It restores the in vitro activity of a range of β-lactams, including ceftazidime, against extended-spectrum β-lactamase-producing pathogens. Two phase I studies assessed the safety and pharmacokinetics of avibactam in healthy subjects when administered alone or with ceftazidime.

METHODS

The first study (NXL104-1001) was a placebo-controlled, single-ascending dose study assessing avibactam 50, 100, 250, 500, 1000, 1500 or 2000 mg given as a 30-min intravenous infusion. After a 7-day washout, subjects in the 250 and 500 mg dosing groups received a second avibactam dose with concomitant ceftazidime 1000 or 2000 mg, respectively. The second study (NXL104-1002) was performed in two parts. Part 1 assessed multiple-ascending doses of avibactam. Subjects were randomized to receive avibactam 500, 750 or 1000 mg every 8 h (q8 h) over 5 days, or ceftazidime-avibactam 2000-500 mg q8 h over 10 days. Part 2 assessed bioavailability of avibactam after a single oral dose (500 mg) relative to a single 30-min intravenous infusion (500 mg).

RESULTS

No serious or severe adverse events were reported in either study. Avibactam exposure generally increased proportionally to dose and there was no trend for accumulation after multiple doses. Almost all avibactam was excreted largely unchanged in the urine within the first 6 h. Concomitant ceftazidime did not affect avibactam's safety and pharmacokinetic profile. Avibactam exposure after oral dosing was very low at 6.2 % of that observed after intravenous infusion.

CONCLUSION

Avibactam was generally well tolerated across all dosing regimens, when given alone or with ceftazidime. Avibactam exposure was dose related in both studies, and avibactam pharmacokinetics were linear and not affected by ceftazidime.

Determination of avibactam and ceftazidime in human plasma samples by LC-MS

AIM

Avibactam, a novel non-β-lactam β-lactamase inhibitor co-administrated with the β-lactam antibiotic ceftazidime, is in clinical development. The need to evaluate its PK and PD requires accurate and reliable bioanalytical methods.

METHODS

We describe LC-MS/MS methods for the determination of avibactam and ceftazidime in human plasma. Avibactam was extracted using weak anionic exchange solid-phase extraction and analyzed on an amide column. Ceftazidime was extracted using protein precipitation and analyzed on a C18 column. Calibration curves were established over 10-10,000 ng/ml (avibactam) and 43.8-87,000 ng/ml (ceftazidime).

RESULTS & CONCLUSION

Method validation, cross-validation between three laboratories and incurred sample re-analysis demonstrated method robustness. The methods were successfully applied to multiple clinical studies.

Ceftazidime-Avibactam: A Novel Cephalosporin/β-Lactamase Inhibitor Combination for the Treatment of Resistant Gram-negative Organisms

PURPOSE

Multidrug-resistant gram-negative bacterial infections have emerged as a major threat in hospitalized patients. Treatment options are often inadequate and, as a result, these infections are associated with high mortality. A cephalosporin and a novel synthetic non-β-lactam, β-lactamase inhibitor, ceftazidime-avibactam, is approved for the treatment of serious infections caused by resistant gram-negative bacteria. This article reviews the spectrum of activity, clinical pharmacology, pharmacodynamic and pharmacokinetic properties, clinical efficacy and tolerability, and dosing and administration of ceftazidime-avibactam.

METHODS

Searches of MEDLINE and International Pharmaceutical Abstracts from 1980 to September 2015 were conducted by using the search terms ceftazidime, avibactam, and ceftazidime-avibactam. Abstracts from Infectious Disease Week (2014-2015), the Interscience Conference on Antimicrobial Agents and Chemotherapy (2014-2015), and the European Congress of Clinical Microbiology and Infectious Diseases were also searched.

FINDINGS

Ceftazidime, a third-generation cephalosporin, when combined with avibactam has a significant improvement in its activity against β-lactamase-producing gram-negative pathogens, including extended-spectrum β-lactamases, AmpC β-lactamases, Klebsiella pneumoniae carbapenemase-producing Enterobacteriaceae, and multidrug-resistant Pseudomonas aeruginosa. Data from 2 Phase II and 1 Phase III clinical trial are available. In the Phase II trial of patients with complicated intra-abdominal infections, ceftazidime-avibactam produced clinical cure rates comparable to meropenem (91.2% vs 93.4%). Similarly, patients receiving ceftazidime-avibactam in a Phase II study of complicated urinary tract infections had clinical and microbiologic response rates similar to those receiving imipenem-cilastatin (70.4% and 71.4% microbiologic success rates, respectively). A Phase III trial compared ceftazidime-avibactam to best available therapy for the treatment of ceftazidime-resistant organisms. Clinical response and microbiological response for ceftazidime-avibactam versus best available therapy was comparable (90.9% and 91.2% clinical response, respectively); (81.8% and 63.5% microbiological response, respectively).

IMPLICATIONS

Currently, ceftazidime-avibactam is approved for the indications of complicated intra-abdominal infections (with metronidazole) and complicated urinary tract infections. Clinical trials published to date on this antimicrobial agent have shown its excellent safety and tolerability. This new combination agent has a role, but its use should be limited to patients without other treatment options in the empiric and documented treatment of multidrug-resistant gram-negative organisms. Further investigation is needed in patients with carbapenemase-producing Enterobacteriaceae and multidrug-resistant P aeruginosa who have bacteremia or nosocomial or ventilator-associated pneumonia. It is imperative that ceftazidime-avibactam be used in a responsible manner so that its effectiveness can be retained.

The β-Lactams Strike Back: Ceftazidime-Avibactam

Gram-negative resistance has reached a crucial point, with emergence of pathogens resistant to most or all available antibiotics. Ceftazidime-avibactam is a newly approved agent combining ceftazidime and a novel β-lactamase inhibitor with activity against multidrug-resistant gram-negative bacteria. Avibactam has increased potency and expanded spectrum of inhibition of class A and C β-lactamases relative to available β-lactamase inhibitors, including extended-spectrum β-lactamases, AmpC, and Klebsiella pneumoniae carbapenemase (KPC) enzymes. Avibactam expands ceftazidime's spectrum of activity to include many ceftazidime- and carbapenem-resistant Enterobacteriaceae and Pseudomonas aeruginosa. Early clinical data indicate that ceftazidime-avibactam is effective and well tolerated in patients with complicated urinary tract infections (cUTIs) and complicated intraabdominal infections (cIAI). In a phase II trial of patients with cUTIs, ceftazidime-avibactam produced similar rates of clinical and microbiologic success compared with imipenem-cilastatin (70.5% and 71.4% microbiologic success rates, respectively). Likewise, patients receiving ceftazidime-avibactam plus metronidazole in a phase II study of patients with cIAI had similar response rates to those receiving meropenem (91.2% and 93.4% clinical success rates, respectively). Based on available in vitro, in vivo, and phase II trial data, as well as preliminary phase III trial results in ceftazidime-resistant, gram-negative cUTI and cIAI, ceftazidime-avibactam received U.S. Food and Drug Administration approval for treatment of cUTI, including pyelonephritis, and cIAI, in combination with metronidazole, in adult patients with limited or no alternative treatment options. The approved dosage, ceftazidime 2 g-avibactam 0.5 g administered as a 2-hour infusion every 8 hours, was selected based on pharmacodynamic analysis and available clinical data. This dosage is under further investigation in patients with cUTI, cIAI, and nosocomial or ventilator-associated pneumonia. The current body of evidence suggests that ceftazidime-avibactam is a promising addition to our therapeutic armamentarium with potential to answer an urgent unmet medical need. Further data in highly resistant gram-negative infections, particularly those caused by KPC-producing Enterobacteriaceae, are needed. As it is introduced into clinical use, careful stewardship and rational use are essential to preserve ceftazidime-avibactam's potential utility.

Randomized pharmacokinetic and drug-drug interaction studies of ceftazidime, avibactam, and metronidazole in healthy subjects

We assessed pharmacokinetic and safety profiles of ceftazidime-avibactam administered ± metronidazole, and whether drug-drug interactions exist between ceftazidime and avibactam, or ceftazidime-avibactam and metronidazole. The first study (NCT01430910) involved two cohorts of healthy subjects. Cohort 1 received ceftazidime-avibactam (2000-500 mg) as a single infusion or as multiple intravenous infusions over 11 days to evaluate ceftazidime-avibactam pharmacokinetics. Cohort 2 received ceftazidime, avibactam, or ceftazidime-avibactam over 4 days to assess drug-drug interaction between ceftazidime and avibactam. The second study (NCT01534247) assessed interaction between ceftazidime-avibactam and metronidazole in subjects receiving ceftazidime-avibactam (2000-500 mg), metronidazole (500 mg), or metronidazole followed by ceftazidime-avibactam over 4 days. In all studies, subjects received a single-dose on the first and final days, and multiple-doses every 8 h on intervening days. Concentration-time profiles for ceftazidime and avibactam administered as single- or multiple-doses separately or together with/without metronidazole were similar. There was no evidence of time-dependent pharmacokinetics or accumulation. In both interaction studies, 90% confidence intervals for geometric least squares mean ratios of area under the curve and maximum plasma concentrations for each drug were within the predefined interval (80-125%) indicating no drug-drug interaction between ceftazidime and avibactam, or ceftazidime-avibactam and metronidazole. There were no safety concerns. In conclusion, pharmacokinetic parameters and safety of ceftazidime, avibactam, and metronidazole were similar after single and multiple doses with no observed drug-drug interaction between ceftazidime and avibactam, or ceftazidime-avibactam and metronidazole.

Ceftazidime-avibactam for the treatment of complicated urinary tract infections and complicated intra-abdominal infections

Treatment of complicated urinary tract infections and complicated intra-abdominal infections is increasingly difficult due to the rising prevalence of multidrug-resistant Gram-negative bacteria. Ceftazidime-avibactam is a combination of the established third-generation cephalosporin ceftazidime with avibactam, a novel non-β-lactam β-lactamase inhibitor, which restores the activity of ceftazidime against many β-lactamase-producing Gram-negative bacteria, including extended-spectrum β-lactamases and Klebsiella pneumoniae carbapenemases. Clinical and nonclinical studies supporting the safety and efficacy of ceftazidime-avibactam include microbiological surveillance studies of clinically relevant pathogens, in vivo animal models of infection, pharmacokinetic/pharmacodynamic target attainment analyses, Phase I clinical pharmacology studies, and Phase II/III studies in the treatment of complicated intra-abdominal infections and complicated urinary tract infections, including patients with ceftazidime-nonsusceptible Gram-negative infections.

Effect of age and sex on the pharmacokinetics and safety of avibactam in healthy volunteers

PURPOSE

Avibactam is a novel non-β-lactam β-lactamase inhibitor currently being assessed in combination with ceftazidime, ceftaroline fosamil, and aztreonam. The objectives of this study were to investigate the pharmacokinetics, safety, and tolerability of avibactam in healthy young (aged 18-45 years) and elderly (aged ≥65 years) volunteers of both sexes.

METHODS

This was a Phase I, open-label study in which healthy volunteers aged ≥18 years were enrolled into 4 cohorts: young male, young female, elderly male, and elderly female (n = 8 in each group). Subjects were excluded if they had any condition requiring regular medication or any other relevant conditions. All subjects received a single dose of avibactam 500 mg/100 mL given intravenously over 30 minutes. Pharmacokinetic measurements included Cmax, Tmax, AUC0-∞, plasma clearance, and t½.

FINDINGS

Within the two age categories the mean age across male and female subjects was well matched. The majority of subjects in the young cohort were black (≥62.5%), whilst the majority of those in the elderly cohorts were white (≥75%). Mean avibactam plasma clearance was similar between the young male, young female, and elderly male cohorts (10.16, 10.34, and 9.82 L/h, respectively), and slightly lower in elderly women (7.98 L/h). Mean Cmax was similar in young male, young female, and elderly female subjects (33.8, 36.9, and 38.4 µg/mL) but lower in elderly male subjects (26.5 µg/mL). Point estimates comparing the ratio of Cmax in male and female subjects over all age groups suggested that Cmax values were 18% lower (90% CI, 30%-5% lower) in male subjects compared with female subjects. Mean AUC0-∞ data were similar between the young male, young female, and elderly male cohorts (49.86, 49.75, and 52.40 µg·h/mL) but higher in elderly women (66.23 µg·h/mL). Point estimates comparing the ratio of AUC0-∞ in elderly and young subjects across both sexes suggested that AUC0-∞ values were 17% higher (90% CI, 5%-31%) in elderly subjects compared with young subjects. The t½ was slightly longer for elderly subjects compared with younger subjects. The most common adverse event was administration/venipuncture site bruising (6 events); all adverse events were mild.

IMPLICATIONS

No notable differences in pharmacokinetics were observed between the male and female cohorts. The generalizability of the study is limited due to its small sample size. However, the small differences observed between the young and elderly cohorts are not sufficient to warrant dosing adjustments based on age.

Effect of canagliflozin on the pharmacokinetics of glyburide, metformin, and simvastatin in healthy participants

Drug-drug interactions between canagliflozin, a sodium glucose co-transporter 2 inhibitor, and glyburide, metformin, and simvastatin were evaluated in three phase-1 studies in healthy participants. In these open-label, fixed sequence studies, participants received: Study 1-glyburide 1.25 mg/day (Day 1), canagliflozin 200 mg/day (Days 4-8), canagliflozin with glyburide (Day 9); Study 2-metformin 2,000 mg/day (Day 1), canagliflozin 300 mg/day (Days 4-7), metformin with canagliflozin (Day 8); Study 3-simvastatin 40 mg/day (Day 1), canagliflozin 300 mg/day (Days 2-6), simvastatin with canagliflozin (Day 7). Pharmacokinetic parameters were assessed at prespecified intervals. Co-administration of canagliflozin and glyburide did not affect the overall exposure (maximum plasma concentration [Cmax ] and area under the plasma concentration-time curve [AUC]) of glyburide and its metabolites (4-trans-hydroxy-glyburide and 3-cis-hydroxy-glyburide). Canagliflozin did not affect the peak concentration of metformin; however, AUC increased by 20%. Though Cmax and AUC were slightly increased for simvastatin (9% and 12%) and simvastatin acid (26% and 18%) following coadministration with canagliflozin, compared with simvastatin administration alone; however, no effect on active 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase inhibitory activity was observed. There were no serious adverse events or hypoglycemic episodes. No drug-drug interactions were observed between canagliflozin and glyburide, metformin, or simvastatin. All treatments were well-tolerated in healthy participants.