The distinctive pharmacokinetic profile of rezafungin, a long-acting echinocandin developed in the era of modern pharmacometrics.

Echinocandin drugs are the current first-line therapy for fungal infections caused by Candida spp. Most patients require once-daily intravenous (IV) administration in a hospital or outpatient setting for treatment, which may negatively impact their quality of life and stress healthcare resources. Similar to other echinocandins, the novel FDA-, EMA-, and Medical and Healthcare Products Regulatory Agency-approved echinocandin, rezafungin (CD101), exhibited strong antifungal activity against several fungal pathogens and a low drug-drug interaction liability, which are important for medically complex patients.

Evaluation of Factors Predictive of Efficacy Among Patients With Complicated Urinary Tract Infection and/or Acute Pyelonephritis.

Background: Antibiotic treatment for complicated urinary tract infections (cUTI)/acute pyelonephritis (AP) is often followed by recurrent bacteriuria in the absence of clinical symptoms. To understand factors predictive of clinical and microbiologic outcomes in patients with cUTI/AP, multivariable analyses were undertaken using pooled data from a global, phase 3 cUTI study.

Methods: Using data from 366 tebipenem pivoxil hydrobromide- and 378 ertapenem-treated patients from the Study to Assess the Efficacy, Safety and Pharmacokinetics of Orally Administered Tebipenem Pivoxil Hydrobromide (SPR994) Compared to Intravenous Ertapenem in Participants With Complicated Urinary Tract Infection (cUTI) or Acute Pyelonephritis (AP) infected with Enterobacterales uropathogens, multivariable analyses for dichotomous efficacy endpoints were performed using logistic regression and pharmacokinetic-pharmacodynamic relationships were evaluated.

Assessment of pharmacokinetics-pharmacodynamics to support omadacycline dosing regimens for the treatment of patients with acute bacterial skin and skin structure infections.

Pharmacokinetic-pharmacodynamic (PK-PD) relationships for efficacy were evaluated using data from omadacycline-treated patients with acute bacterial skin and skin structure infections (ABSSSI) enrolled in two phase 3 studies. Patients received omadacycline 100 mg intravenously (IV) every 12 hours for two doses, followed by 100 mg IV every 24 hours (q24h), with the option to switch to 300 mg oral (PO) q24h after 3 days or 450 mg PO q24h for two doses, followed by 300 mg PO q24h for a total duration of 7-14 days. Clinical response was evaluated at 48-72 hours [early clinical response (ECR)], end of treatment (EOT), and 7-14 days after EOT.

Impact of antibiotic pharmacokinetics in urine on recurrent bacteriuria following treatment of complicated urinary tract infections.

The clinical relevance of bacteriuria following antibiotic treatment of complicated urinary tract infections in clinical trials remains controversial. We evaluated the impact of urine pharmacokinetics on the timing of recurrent bacteriuria in a recently completed trial that compared oral tebipenem pivoxil hydrobromide to intravenous ertapenem. The urinary clearance and urine dwell time of ertapenem were prolonged relative to tebipenem and were associated with a temporal difference in the repopulation of bladder urine with bacteria following treatment, potentially confounding the assessment of efficacy.

Antibody-mediated protection against symptomatic COVID-19 can be achieved at low serum neutralizing titers.

Multiple studies of vaccinated and convalescent cohorts have demonstrated that serum neutralizing antibody (nAb) titers correlate with protection against coronavirus disease 2019 (COVID-19). However, the induction of multiple layers of immunity after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exposure has complicated the establishment of nAbs as a mechanistic correlate of protection (CoP) and hindered the definition of a protective nAb threshold. Here, we show that a half-life-extended monoclonal antibody (adintrevimab) provides about 50% protection against symptomatic COVID-19 in SARS-CoV-2-naïve adults at serum nAb titers on the order of 1:30.

Pharmacokinetic-Pharmacodynamic Target Attainment Analyses Evaluating Omadacycline Dosing Regimens for the Treatment of Patients with Community-Acquired Bacterial Pneumonia Arising from Streptococcus pneumoniae and Haemophilus influenzae.

Omadacycline, a novel aminomethylcycline with activity against Gram-positive and -negative organisms, including Streptococcus pneumoniae and Haemophilus influenzae, is approved in the United States to treat patients with community-acquired bacterial pneumonia (CABP). Using nonclinical pharmacokinetic-pharmacodynamic (PK-PD) targets for efficacy and surveillance data for omadacycline against S. pneumoniae and H.

Pharmacokinetic/Pharmacodynamic Evaluation of the Dipeptidyl Peptidase 1 Inhibitor Brensocatib for Non-cystic Fibrosis Bronchiectasis.

Background And Objective: Brensocatib is an investigational, first-in-class, selective, and reversible dipeptidyl peptidase 1 inhibitor that blocks activation of neutrophil serine proteases (NSPs). The NSPs neutrophil elastase, cathepsin G, and proteinase 3 are believed to be central to the pathogenesis of several chronic inflammatory diseases, including bronchiectasis. In a phase II study, oral brensocatib 10 mg and 25 mg reduced sputum neutrophil elastase activity and prolonged the time to pulmonary exacerbation in patients with non-cystic fibrosis bronchiectasis (NCFBE).

Population Pharmacokinetics of Rezafungin in Patients with Fungal Infections.

Rezafungin is a novel antifungal agent of the echinocandin class with potent activity against species of and Aspergillus, including subsets of resistant strains, and Pneumocystis jirovecii. The objective of this analysis was to develop a population pharmacokinetic (PK) model to characterize the disposition of rezafungin in plasma following intravenous (IV) administration in healthy volunteers and in patients with candidemia and/or invasive candidiasis. The population PK model was based on a previous model from phase 1 data; formal covariate analyses were conducted to identify any relationships between subject characteristics and rezafungin PK variability.

Model-Based Approach for Optimizing Ceftobiprole Dosage in Pediatric Patients.

Ceftobiprole is an advanced-generation cephalosporin for intravenous administration with activity against Gram-positive and Gram-negative organisms. A population pharmacokinetic (PK) model characterizing the disposition of ceftobiprole in plasma using data from patients in three pediatric studies was developed. Model-based simulations were subsequently performed to assist in dose optimization for the treatment of pediatric patients with hospital-acquired or community-acquired pneumonia.

Population Pharmacokinetic Evaluation of Amikacin Liposome Inhalation Suspension in Patients with Treatment-Refractory Nontuberculous Mycobacterial Lung Disease.

Background And Objectives: Use of parenteral amikacin to treat refractory nontuberculous mycobacterial (NTM) lung disease is limited by systemic toxicity. A population pharmacokinetic model was developed using data pooled from two randomized trials to evaluate the pharmacokinetic properties of once-daily amikacin liposome inhalation suspension (ALIS) in patients with treatment-refractory NTM lung disease.

Methods: In phase 2 (TR02-112) and phase 3 (CONVERT) studies, patients with sputum cultures positive for Mycobacterium avium complex (both studies) or M.

Pharmacokinetics and Optimal Dose Selection of Cefazolin for Surgical Prophylaxis of Pediatric Patients.

Cefazolin is an antibiotic frequently used for perioperative prophylaxis. Data from healthy adults and pediatric surgery patients were pooled to refine a previously developed population pharmacokinetic (PK) model and to determine the optimal body weight cutoff for selecting fixed doses of either 1 or 2 g cefazolin to produce exposures in pediatric surgery patients similar to a single 2-g dose in adults. Regardless of dose used, cefazolin was well tolerated in pediatric patients.

Antibacterial Drug Development: A New Approach Is Needed for the Field to Survive and Thrive.

It is often said that the marketplace for new antibiotics is broken. This notion is supported by the observation that many recently-approved antibiotics to treat drug-resistant bacteria have failed commercially in a spectacular fashion. Today, companies with peak market-cap values in excess of USD 500 million to 1 billion prior to product launch regularly sell for pennies on the dollar a few years after market introduction.

Pharmacokinetic-Pharmacodynamic Target Attainment Analyses To Support Dose Selection for ME1100, an Arbekacin Inhalation Solution.

ME1100 (arbekacin inhalation solution) is an inhaled aminoglycoside that is being developed to treat patients with hospital-acquired and ventilator-associated bacterial pneumonia (HABP and VABP, respectively). Pharmacokinetic-pharmacodynamic (PK-PD) target attainment analyses were undertaken to evaluate ME1100 regimens for the treatment of patients with HABP/VABP. The data used included a population pharmacokinetic (PPK) 4-compartment model with 1st-order elimination, nonclinical PK-PD targets from one-compartment and/or infection models, and surveillance data.

Population Pharmacokinetic Analyses for Omadacycline Using Phase 1 and 3 Data.

Omadacycline, a novel aminomethylcycline antibiotic with activity against Gram-positive and -negative organisms, including tetracycline-resistant pathogens, received FDA approval in October 2018 for the treatment of patients with acute bacterial skin and skin structure infections (ABSSSI) and community-acquired bacterial pneumonia (CABP). A previously developed population pharmacokinetic (PK) model based on phase 1 intravenous and oral PK data was refined using data from infected patients. Data from 10 phase 1 studies used to develop the previous model were pooled with data from three additional phase 1 studies, a phase 1b uncomplicated urinary tract infection study, one phase 3 CABP study, and two phase 3 ABSSSI studies.

Concentration-Dependent Activity of Hydromethylthionine on Clinical Decline and Brain Atrophy in a Randomized Controlled Trial in Behavioral Variant Frontotemporal Dementia.

Background: Hydromethylthionine is a potent inhibitor of pathological aggregation of tau and TDP-43 proteins.

Objective: To compare hydromethylthionine treatment effects at two doses and to determine how drug exposure is related to treatment response in bvFTD.

Methods: We undertook a 52-week Phase III study in 220 bvFTD patients randomized to compare hydromethylthionine at 200 mg/day and 8 mg/day (intended as a control).

Concentration-Dependent Activity of Hydromethylthionine on Cognitive Decline and Brain Atrophy in Mild to Moderate Alzheimer's Disease.

Background: Although hydromethylthionine is a potent tau aggregation inhibitor, no difference was found in either of two Phase III trials in mild to moderate Alzheimer's disease (AD) comparing doses in the range 150-250 mg/day with 8 mg/day intended as a control.

Objective: To determine how drug exposure is related to treatment response.

Methods: A sensitive plasma assay for the drug was used in a population pharmacokinetic analysis of samples from 1,162 of the 1,686 patients who participated in either of the Phase III trials with available samples and efficacy outcome data.

Population Pharmacokinetic Analyses for Arbekacin after Administration of ME1100 Inhalation Solution.

ME1100, an inhalation solution of arbekacin, an aminoglycoside, is being developed for the treatment of hospital-acquired and ventilator-associated bacterial pneumonia. The objective of these analyses was to develop a population pharmacokinetic model to describe the arbekacin concentration-time profile in plasma and epithelial lining fluid (ELF) following ME1100 administration. Data were obtained from a postmarketing study for an intravenous (i.

Prediction of lefamulin epithelial lining fluid penetration after intravenous and oral administration using Phase 1 data and population pharmacokinetics methods.

Objectives: Lefamulin is a semi-synthetic intravenous and oral pleuromutilin antibiotic with activity against pathogens commonly associated with community-acquired bacterial pneumonia. Using data from two Phase 1 studies, a population pharmacokinetics (PPK) model for lefamulin in plasma and epithelial lining fluid (ELF) was constructed.

Methods: Plasma pharmacokinetic (PK) data from a crossover, bioavailability, food-effect study and plasma and ELF PK data from a tissue penetration study in normal healthy volunteers were used to construct a PPK model for lefamulin.

Pharmacokinetic/pharmacodynamic target attainment analyses to support intravenous and oral lefamulin dose selection for the treatment of patients with community-acquired bacterial pneumonia.

Objectives: Lefamulin is a semi-synthetic intravenous (iv) and oral pleuromutilin antibiotic active against community-acquired bacterial pneumonia (CABP) pathogens. Pharmacokinetic/pharmacodynamic (PK/PD) target attainment analyses were carried out to evaluate lefamulin 150 mg iv q12h and 600 mg orally q12h under fed and fasted conditions for the treatment of patients with CABP.

Methods: The analyses undertaken used a population PK model based on Phase 1 PK data, non-clinical PK/PD targets for efficacy and in vitro surveillance data for Streptococcus pneumoniae (SP) and Staphylococcus aureus (SA), and Monte Carlo simulation.

Population Pharmacokinetic Analyses for Plazomicin Using Pooled Data from Phase 1, 2, and 3 Clinical Studies.

Plazomicin is an aminoglycoside with activity against multidrug-resistant Plazomicin is dosed on a milligram-per-kilogram-of-body-weight basis and administered by a 30-min intravenous infusion every 24 h, with dose adjustments being made for renal impairment and a body weight (BW) of ≥125% of ideal BW. A population pharmacokinetic analysis was performed to identify patient factors that account for variability in pharmacokinetics and to determine if dose adjustments are warranted based on covariates. The analysis included 143 healthy adults and 421 adults with complicated urinary tract infection (cUTI), acute pyelonephritis, bloodstream infection, or hospital-acquired bacterial pneumonia/ventilator-associated bacterial pneumonia (HABP/VABP) from seven studies (phases 1 to 3).

Time for Precision: A World Without Susceptibility Breakpoints.

Interpretive criteria for in vitro susceptibility testing criteria, "susceptibility breakpoints," underpin the evaluation and selection of antimicrobial regimens. However, despite their strengths, susceptibility breakpoints are a relatively blunt instrument employed to address an extremely complex question-what is the likelihood of treatment success for individual patients? With regard to evaluating patients on a case-by-case basis, breakpoints merely allow us to account for pathogen susceptibility. This approach precludes consideration of drug exposures achieved in patients, thus overlooking half of the equation for predicting treatment success.