Pharmacokinetics, Mass Balance, Safety, and Tolerability of Obeldesivir in Healthy Participants.

There is an unmet need for safe and efficacious oral therapies for COVID-19 with low potential for drug-drug interactions. Obeldesivir is an orally administered nucleoside prodrug that has shown antiviral potency in nonclinical studies against SARS-CoV-2 and its circulating variants. Obeldesivir is metabolized to the active nucleoside triphosphate (GS-443902), which acts as an inhibitor of the SARS-CoV-2 RNA-dependent RNA polymerase, thereby inhibiting viral RNA synthesis.

Pharmacokinetics, Safety, and Efficacy of Letermovir for Cytomegalovirus Prophylaxis in Adolescent Hematopoietic Cell Transplantation Recipients.

Introduction: Letermovir is a cytomegalovirus (CMV) terminase complex inhibitor approved for prophylaxis of CMV infection and disease in adult CMV-seropositive allogeneic hematopoietic cell transplantation (allo-HCT) recipients (R+). We report pharmacokinetics (PK), safety, and efficacy of letermovir in adolescent (12-18 years) allogeneic HCT recipients from an ongoing clinical study.

Methods: In this phase 2b, multicenter, open-label study (NCT03940586), 28 adolescents received 480 mg letermovir [240 mg with cyclosporin A (CsA)] once daily orally or intravenously.

Quantification of clesrovimab, an investigational, half-life extended, anti-respiratory syncytial virus protein F human monoclonal antibody in the nasal epithelial lining fluid of healthy adults.

Background: Clesrovimab (MK-1654) is an investigational, half-life extended human monoclonal antibody (mAb) against RSV F glycoprotein in clinical trials as a prophylactic agent against RSV infection for infants.

Methods: This adult study measured clesrovimab concentrations in the serum and nasal epithelial lining fluid (ELF) to establish the partitioning of the antibody after dosing. Clesrovimab concentrations in the nasal ELF were normalized for sampling dilution using urea concentrations from ELF and serum.

Bictegravir/emtricitabine/tenofovir alafenamide plus doravirine in highly treatment-experienced men with multidrug-resistant HIV.

Objective: To evaluate the safety and efficacy of switching highly treatment-experienced people with HIV (HTE PWH) from rilpivirine/emtricitabine/tenofovir alafenamide (RPV/FTC/TAF) plus dolutegravir (DTG) to bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) plus doravirine (DOR). A pharmacokinetic (PK) analysis was conducted to assess the potential interaction between BIC and DOR.

Design And Methods: This open-label switch trial enrolled HTE PWH from a primary care private practice in the United States.

Elbasvir/grazoprevir in children aged 3-18 years with chronic HCV genotype 1 or 4 infection: a pharmacokinetic modeling study.

Background: Approximately 3.5 million children and adolescents worldwide are chronically infected with HCV. This study uses pharmacokinetic modeling to identify pediatric doses of elbasvir/grazoprevir (EBR/GZR) that achieve plasma concentrations similar to those seen in adults receiving the approved fixed-dose combination regimen of EBR/GZR.

A phase I study to evaluate safety, pharmacokinetics, and pharmacodynamics of respiratory syncytial virus neutralizing monoclonal antibody MK-1654 in healthy Japanese adults.

Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infection among all infants worldwide and remains a significant cause of morbidity and mortality. To address this unmet medical need, MK-1654, a half-life extended RSV neutralizing monoclonal antibody, is in clinical development for the prevention of RSV disease in infants. This was a phase I, randomized, placebo-controlled, single-site, double-blind trial of MK-1654 in 44 healthy Japanese adults.

Forward and reverse translational approaches to predict efficacy of neutralizing respiratory syncytial virus (RSV) antibody prophylaxis.

Background: Neutralizing mAbs can prevent communicable viral diseases. MK-1654 is a respiratory syncytial virus (RSV) F glycoprotein neutralizing monoclonal antibody (mAb) under development to prevent RSV infection in infants. Development and validation of methods to predict efficacious doses of neutralizing antibodies across patient populations exposed to a time-varying force of infection (i.

Immune-viral dynamics modeling for SARS-CoV-2 drug development.

Coronavirus disease 2019 (COVID-19) global pandemic is caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) viral infection, which can lead to pneumonia, lung injury, and death in susceptible populations. Understanding viral dynamics of SARS-CoV-2 is critical for development of effective treatments. An Immune-Viral Dynamics Model (IVDM) is developed to describe SARS-CoV-2 viral dynamics and COVID-19 disease progression.

Pharmacokinetics and Pharmacodynamics of Ceftolozane/Tazobactam in Critically Ill Patients With Augmented Renal Clearance.

Objective: To determine whether established ceftolozane/tazobactam (C/T) dosing is adequate for patients with augmented renal clearance (ARC) and bacterial infection.

Methods: ARC (creatinine clearance [CrCl] ≥ 130 mL/min) was confirmed by directly measured CrCl in 11 critically ill patients in a phase 1 pharmacokinetics study. Patients received 3 g C/T (ceftolozane 2 g/tazobactam 1 g) as a 60-minute intravenous infusion.

Evaluation of Pharmacokinetic Drug Interactions of the Direct-Acting Antiviral Agents Elbasvir and Grazoprevir with Pitavastatin, Rosuvastatin, Pravastatin, and Atorvastatin in Healthy Adults.

Background: Many people infected with hepatitis C virus have comorbidities, including hypercholesterolemia, that are treated with statins. In this study, we evaluated the drug-drug interaction potential of the hepatitis C virus inhibitors elbasvir (EBR) and grazoprevir (GZR) with statins. Pitavastatin, rosuvastatin, pravastatin, and atorvastatin are substrates of organic anion-transporting polypeptide 1B, whereas rosuvastatin and atorvastatin are also breast cancer resistance protein substrates.

A Phase 1 Randomized, Double-Blind, Placebo-Controlled Trial to Assess the Safety, Tolerability, and Pharmacokinetics of a Respiratory Syncytial Virus Neutralizing Monoclonal Antibody MK-1654 in Healthy Adults.

Respiratory syncytial virus (RSV) is the leading cause of acute lower respiratory tract infection and related morbidity and mortality in infants. Passive immunization with an RSV-neutralizing antibody can provide rapid protection to this vulnerable population. Proof-of-concept for this approach has been demonstrated by palivizumab; however, the use of this antibody is generally restricted to the highest-risk infants due to monthly dosing requirements and its cost.

Lung penetration, bronchopulmonary pharmacokinetic/pharmacodynamic profile and safety of 3 g of ceftolozane/tazobactam administered to ventilated, critically ill patients with pneumonia.

Objectives: Ceftolozane/tazobactam is approved for hospital-acquired/ventilator-associated bacterial pneumonia at double the dose (i.e. 2 g/1 g) recommended for other indications.

A Single- and Multiple-Dose Study to Evaluate the Pharmacokinetics of Fixed-Dose Grazoprevir/Elbasvir in Healthy Chinese Participants.

Purpose: The burden of hepatitis C virus infection is particularly high in Asian countries, and new treatments are urgently needed. The purpose of this study was to characterize the pharmacokinetics (PK) and safety of the fixed-dose combination tablet of elbasvir/grazoprevir in healthy Chinese participants.

Patient And Methods: In this Phase I, single-site, open-label, 3-period study in healthy Chinese adults, participants received a single tablet of elbasvir 50 mg/grazoprevir 100 mg, followed by blood sampling for up to 96 hrs (http://www.

Fine-Needle Aspiration for the Evaluation of Hepatic Pharmacokinetics of Vaniprevir: A Randomized Trial in Patients With Hepatitis C Virus Infection.

Fine-needle aspiration (FNA) for serial hepatic sampling may be an efficient and less invasive alternative to core needle biopsy (CNB), the current standard for liver tissue sampling. In this randomized, open-label trial in 31 participants with hepatitis C virus genotype 1 infection (NCT01678131/Merck protocol PN048), we evaluated the feasibility of using FNA to obtain human liver tissue samples appropriate for measuring hepatic pharmacokinetics (PK), using vaniprevir as a tool compound. The primary end point was successful retrieval of liver tissue specimens with measurable vaniprevir concentrations at two of three specified FNA time points.

The pharmacogenetics of OATP1B1 variants and their impact on the pharmacokinetics and efficacy of elbasvir/grazoprevir.

To evaluate the effect of genetic variants on grazoprevir pharmacokinetics and efficacy. A retrospective analysis of 1578 hepatitis C virus-infected participants from ten Phase II/III clinical trials. Relative to noncarriers of the risk allele, geometric mean ratios (95% CI) of grazoprevir area under curve (AUC) were: rs4149056 (risk allele C), one copy, 1.

Assessment of Drug Interaction Potential Between the Hepatitis C Virus Direct-Acting Antiviral Agents Elbasvir/Grazoprevir and the Nucleotide Analog Reverse-Transcriptase Inhibitor Tenofovir Disoproxil Fumarate.

Treatment of individuals coinfected with hepatitis C virus (HCV) and human immunodeficiency virus (HIV) requires careful consideration of potential drug-drug interactions. We evaluated the pharmacokinetic interaction of the direct-acting antiviral agents elbasvir and grazoprevir coadministered with the nucleotide reverse transcriptase inhibitor tenofovir disoproxil fumarate (TDF). Three open-label, multidose studies in healthy adults were conducted.

Pharmacokinetic Interactions Between the Fixed-Dose Combinations of Elvitegravir/Cobicistat/Tenofovir Disoproxil Fumarate/Emtricitabine and Elbasvir/Grazoprevir in Healthy Adult Participants.

Treatment of individuals coinfected with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) requires careful consideration of potential drug-drug interactions. The pharmacokinetic interaction of the HCV fixed-dose combination treatment of elbasvir/grazoprevir (EBR/GZR) when coadministered with the fixed-dose combination HIV treatment of elvitegravir/cobicistat/tenofovir disoproxil fumarate/emtricitabine (EVG/COB/TDF/FTC) was evaluated in 22 healthy adults. In period 1, oral doses of EVG/COB/TDF/FTC (150 mg/150 mg/300 mg/200 mg) were administered once daily for 7 days.

Ceftolozane-Tazobactam Population Pharmacokinetics and Dose Selection for Further Clinical Evaluation in Pediatric Patients with Complicated Urinary Tract or Complicated Intra-abdominal Infections.

Ceftolozane-tazobactam, a combination of the novel antipseudomonal cephalosporin ceftolozane and the well-established extended-spectrum β-lactamase inhibitor tazobactam, is approved for treating complicated urinary tract infections (cUTI) and complicated intra-abdominal infections (cIAI) in adults. To determine doses likely to be safe and efficacious in phase 2 pediatric trials for the same indications, single-dose ceftolozane-tazobactam plasma pharmacokinetic data from a recently completed phase 1 trial in pediatric patients (birth to <18 years old) with proven/suspected Gram-negative bacterial infections, along with pharmacokinetic data from 12 adult studies, were integrated into a population pharmacokinetic (popPK) analysis. Two-compartment linear models with first-order elimination described the concentration-time profiles of ceftolozane and tazobactam in pediatric patients well.

Elbasvir/Grazoprevir in People With Hepatitis C Genotype 1 Infection and Child-Pugh Class B Cirrhosis: The C-SALT Study.

Introduction: Treatment options are limited for people infected with hepatitis C virus (HCV) with decompensated liver disease. The C-SALT study assessed elbasvir (EBR) plus grazoprevir (GZR) in individuals with HCV genotype 1 infection and Child-Pugh class B (CP-B) cirrhosis.

Methods: In this 12-week, phase 2, nonrandomized, open-label study (NCT02115321; Protocol MK-5172-059), participants with CP-B cirrhosis received EBR 50 mg plus GZR 50 mg once daily, and a control group of noncirrhotic participants received EBR 50 mg plus GZR 100 mg once daily.

Safety and efficacy of elbasvir/grazoprevir in Asian participants with hepatitis C virus genotypes 1 and 4 infection.

Background And Aim: Estimates suggest that in Asia, more than 31 million individuals have hepatitis C virus infection. The present analysis was conducted to assess the efficacy and safety of elbasvir/grazoprevir in Asian participants enrolled in the elbasvir/grazoprevir phase 2/3 clinical trials.

Methods: This is an integrated analysis of data from 12 international phase 2/3 clinical trials.

Pharmacokinetic Interactions between the Hepatitis C Virus Inhibitors Elbasvir and Grazoprevir and HIV Protease Inhibitors Ritonavir, Atazanavir, Lopinavir, and Darunavir in Healthy Volunteers.

The combination of the hepatitis C virus (HCV) nonstructural protein 5A (NS5A) inhibitor elbasvir and the NS3/4A protease inhibitor grazoprevir is a potent, once-daily therapy indicated for the treatment of chronic HCV infection in individuals coinfected with human immunodeficiency virus (HIV). We explored the pharmacokinetic interactions of elbasvir and grazoprevir with ritonavir and ritonavir-boosted HIV protease inhibitors in three phase 1 trials. Drug-drug interaction trials with healthy participants were conducted to evaluate the effect of ritonavir on the pharmacokinetics of grazoprevir (= 10) and the potential two-way pharmacokinetic interactions of elbasvir (= 30) or grazoprevir (= 39) when coadministered with ritonavir-boosted atazanavir, lopinavir, or darunavir.

Pharmacokinetics of elbasvir and grazoprevir in subjects with end-stage renal disease or severe renal impairment.

Purpose: To describe the phase 1 and population pharmacokinetic investigations that support dosing recommendations for elbasvir/grazoprevir (EBR/GZR) in hepatitis C virus-infected people with advanced chronic kidney disease.

Methods: This was an open-label, two-part, multiple-dose trial (MK-5172 PN050; NCT01937975) in 24 non-HCV-infected participants with end-stage renal disease (ESRD) or severe renal impairment who received once-daily EBR 50 mg and GZR 100 mg for 10 days. Population pharmacokinetic analyses from the phase 3 C-SURFER study (PN052, NCT02092350) were also conducted.

Assessment of drug interaction potential between the HCV direct-acting antiviral agents elbasvir/grazoprevir and the HIV integrase inhibitors raltegravir and dolutegravir.

Background: Elbasvir/grazoprevir is a once-daily fixed-dose combination therapy for the treatment of chronic HCV infection, including HCV/HIV coinfection.

Objectives: To evaluate the pharmacokinetic interaction of elbasvir and grazoprevir with raltegravir or dolutegravir.

Methods: Three open-label trials in healthy adult participants were conducted.

Pharmacokinetics and Safety of Single Intravenous Doses of Ceftolozane/Tazobactam in Children With Proven or Suspected Gram-Negative Infection.

Background: Drug-resistant Gram-negative bacteria are a growing threat to children; thus new antibiotics are needed to treat infections caused by these pathogens. Ceftolozane/tazobactam is active against many Gram-negative pathogens and is approved for treatment of complicated intra-abdominal and urinary tract infections in adults, but has not been evaluated in children.

Methods: This phase 1, noncomparative, open-label, multicenter study characterized the pharmacokinetics (by noncompartmental analysis), safety, and tolerability of single intravenous doses of ceftolozane/tazobactam in pediatric patients (birth [7 days postnatal] to < 18 years of age) with proven/suspected Gram-negative infection or receiving perioperative prophylaxis (clinicaltrials.