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. Blood was collected for intensive (n = 14) plasma concentrations of letermovir. Intensive PK data were used for dose confirmation. Target exposure range 34,400-100,000 h × ng/mL for pediatric median exposures was based on model-predicted phase 3 population PK simulations in adult HCT recipients.

RESULTS

All participants were CMV-seropositive (body weight 28.7-95.0 kg). Of 12 PK-evaluable participants, 8 receiving 480 mg letermovir without CsA and 4 receiving 240 mg letermovir with CsA achieved exposures comparable to the adult exposure range. Exposure above the target but below the adult clinical program maximum was observed in 1 patient. Safety was consistent with previously described safety in adults. The proportion of participants with clinically significant CMV infection through week 24 post-HCT was comparable (24%) to that in the pivotal phase 3 study in adults (37.5%).

CONCLUSIONS

Administration of adult letermovir doses in this adolescent cohort resulted in exposures within adult clinical program margins and was associated with safety and efficacy similar to adults. Results support a letermovir dose of 480 mg (240 mg with CsA) in adolescent allo-HCT recipients.

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. Furthermore, in vitro RSV neutralization of human nasal ELF following dosing was also measured to examine the activity of clesrovimab in the nasal compartment.

FINDINGS

mAbs with YTE mutations are reported in literature to partition ∼1-2 % of serum antibodies into nasal mucosa. Nasal: serum ratios of 1:69-1:30 were observed for clesrovimab in two separate adult human trials after urea normalization, translating to 1.4-3.3 % of serum concentrations. The nasal PK and estimates of peripheral volume of distribution correlated with higher extravascular distribution of clesrovimab. These higher concentration of the antibody in the nasal ELF corroborated with the nasal sample's ability to neutralize RSV ex vivo. An overall trend of decreased viral plaque AUC was also noted with increasing availability of clesrovimab in the nasal ELF from a human RSV challenge study.

INTERPRETATION

Along with its extended half-life, the higher penetration of clesrovimab into the nasal epithelial lining fluid and the associated local increase in RSV neutralization activity could offer infants better protection against RSV infection.

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. Eligible participants were male, aged ≥45 years, with documented viral resistance to protease inhibitors, nucleoside reverse transcriptase inhibitors, and/or nonnucleoside reverse transcriptase inhibitors but no resistance to RPV or DOR, and no K65R or T69 insertion mutations. Virologic suppression (≤50 copies/ml) while on RPV/FTC/TAF plus DTG for ≥6 months was required prior to enrollment. The primary endpoint of the study was virologic suppression (<50 and <200 copies/ml) at 48 weeks. Secondary endpoints included safety, tolerability, changes in body mass index (BMI), and identification of PK parameters of BIC and DOR.

RESULTS

Twenty males [median age: 65 years (range, 46-74), median time since HIV diagnosis: 37 years (range, 12-42)] completed the study. BIC/FTC/TAF plus DOR was well tolerated with no serious or treatment-related adverse events reported and no appreciable changes in BMI from baseline to Week 48. At Week 48, 100% of participants had <50 viral copies/ml. PK parameters for BIC and DOR ( n  = 10) were consistent with published data.

CONCLUSIONS

Switching from RPV/FTC/TAF plus DTG to BIC/FTC/TAF plus DOR was well tolerated and efficacious in HTE men aged ≥45 years with HIV.

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.

PATIENTS AND METHODS

We conducted a nonrandomized, single-arm, multicenter, open-label phase 2b trial in children and adolescents aged 3 to <18 years with chronic HCV genotype 1 or 4 infection (NCT03379506). Pharmacokinetic data were used to bridge efficacy and safety data from adults to children in a stepwise (oldest to youngest) manner. A total of 57 participants were enrolled: cohort 1 (aged 12 to <18 y), n=22; cohort 2 (aged 7 to <12 y), n=17; and cohort 3 (aged 3 to <7 y), n=18.

RESULTS

Steady-state plasma exposures were achieved by week 4 for EBR and GZR in all cohorts and daily dosing achieved geometric mean steady-state area under the concentration-time curve at 0-24 hours that fell within comparability bounds established for adults. All participants achieved sustained virologic response 12 weeks after completing treatment (ie, undetectable HCV RNA 12 wk following completion of treatment). Headache (n=4), fatigue (n=4), and nausea (n=2) were the most common treatment-related adverse events (all mild or moderate); no participant discontinued because of an adverse event.

CONCLUSIONS

Pediatric EBR/GZR pharmacokinetic models were successfully developed based on complex adult population pharmacokinetic models. At appropriate age-related doses, EBR/GZR is safe and effective in pediatric and adolescent participants with HCV infection.

623. Preliminary Dosing for Adolescent Hematopoietic Stem-Cell Transplant (HSCT) Recipients Based on Pharmacokinetic (PK), Safety, and Efficacy Data of Letermovir (LET) for Cytomegalovirus (CMV) Prophylaxis

Background

LET is a CMV terminase complex inhibitor approved for prophylaxis of CMV infection and disease in adult CMV-seropositive allogeneic HSCT recipients. Objectives of this ongoing study are to evaluate PK, safety, and efficacy of LET for CMV prophylaxis in adolescent allogeneic HSCT recipients (aged 12 to &lt; 18 years).

Methods

This is a Phase 2b nonrandomized, multicenter, open-label, sequential dose escalation study (NCT03940586). Participants (pts) were divided into 3 age groups, the oldest (AG1) comprising adolescents. AG1 pts received the recommended adult 480 mg LET dose (240 mg with cyclosporine A [CsA]) once-daily orally (PO) or intravenously (IV). Pediatric target exposures were based on model-predicted Phase 3 population PK simulations for adult HSCT recipients: 16,900 h.ng/mL (480 mg PO without [w/o] CsA) to 147,800 h.ng/mL (480 mg IV w/o CsA). PK parameters were determined by non-compartmental analysis for 14/28 AG1 pts.

Results

All 28 AG1 pts enrolled were CMV-seropositive (median age: 13.5 [range, 12–17] years; median weight: 53.8 [range, 28.7–95.0] kg; White: 53.6%).

PK (N=14): Of 13 evaluable AG1 pts (weight, 30.4–87.7 kg), 8 received 480 mg LET alone (oral/IV; Table 1); 6/8 achieved exposures within the target range and 2/8 (oral, n=1; IV, n=1) achieved exposures above the target range but below the maximum observed in the development program. 5 AG1 pts received 240 mg LET (oral/IV) with CsA; 5/5 achieved exposures within the target range.

Safety (N=28): No major safety concerns were reported for AG1 pts receiving LET, similar to the adult LET safety profile.

Efficacy (N=25): The proportion of AG1 pts receiving LET with clinically significant CMV infection (CMV disease/pre-emptive treatment for CMV viremia) through week 24 post-HSCT was similar (24%) to that for adults receiving LET in the pivotal Phase 3 study (37.5%).

Conclusion

Administration of adult LET doses for CMV prophylaxis post-HSCT in this adolescent cohort resulted in exposures within the development program safety margins, and was associated with similar efficacy and safety to LET use in adult patients. Preliminary results support 480 mg (240 mg with CsA) as an oral and IV LET dose in adolescent HSCT recipients, with a final dose recommendation after study completion.

Disclosures

Andreas H. Groll, MD, Amplyx, Astellas, Basilea, F2G, Gilead Sciences, Merck Sharp & Dohme, and Pfizer: Advisor/Consultant|Astellas, Basilea, F2G, Gilead Sciences, Merck Sharp & Dohme, and Pfizer: Served at the speakers’ bureau|Gilead Sciences, Merck Sharp & Dohme, and Pfizer: Grant/Research Support Johannes H. Schulte, MD, German Cancer Consortium (DKTK): Support by Ali Bulent Antmen, MD, PhD, Novo Nordisk, Pfizer, Roche, Takeda: Advisor/Consultant Valerie L. Teal, MS, Merck & Co., Inc.: Stocks/Bonds|Merck Sharp & Dohme LLC: Current or former employee Barbara A. Haber, MD, Merck & Co., Inc.: Stocks/Bonds|Merck Sharp & Dohme LLC: Current or former employee Luzelena Caro, PhD, Merck & Co., Inc.: Stocks/Bonds|Merck Sharp & Dohme LLC: Current or former employee Jacqueline B. McCrea, PharmD, Merck & Co., Inc.: Stocks/Bonds|Merck Sharp & Dohme LLC: Current or former employee Craig Fancourt, PhD, Merck & Co., Inc.: Stocks/Bonds|Merck Sharp & Dohme LLC: Current or former employee Karsten Menzel, PhD, Merck & Co., Inc.: Stocks/Bonds|Merck Sharp & Dohme LLC: Current or former employee Cyrus Badshah, MD, PhD, Merck & Co., Inc.: Stocks/Bonds|Merck Sharp & Dohme LLC: Current or former employee.

A Phase 1 Study to Evaluate Safety, Pharmacokinetics, and Pharmacodynamics of Respiratory Syncytial Virus (RSV) 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. The safety, tolerability, pharmacokinetics, antidrug antibodies (ADAs), and serum neutralizing antibody (SNA) titers against RSV were evaluated for 1 year after a single intramuscular (i.m.) or intravenous (i.v.) dose of MK‐1654 or placebo in five groups (100 mg i.m., 300 mg i.m., 300 mg i.v., 1000 mg i.v., or placebo). MK‐1654 was generally well‐tolerated in Japanese adults. There were no serious drug‐related adverse events (AEs) reported in any MK‐1654 recipient and no discontinuations due to any AEs in the study. The half‐life of MK‐1654 ranged from 76 to 91 days across dosing groups. Estimated bioavailability was 86% for 100 mg i.m. and 77% for 300 mg i.m. One participant out of 33 (3.0%) developed detectable ADA with no apparent associated AEs. The RSV SNA titers increased in a dose‐dependent manner among participants who received MK‐1654. These data support the development of MK‐1654 for use in Japanese infants.

1013. Predicting RSV Efficacy for MK-1654 in Temperate and Tropical Climates using MBMA and Clinical Trial Simulation to Account for Seasonal Differences in RSV Force-of-Infection

Background

MK-1654 is a respiratory syncytial virus (RSV) F glycoprotein neutralizing monoclonal antibody under development to prevent RSV infection in infants. A model-based meta-analysis (MBMA) describing the relationship between RSV serum neutralizing activity (SNA) and clinically relevant endpoints (e.g. incidence rates) in humans, including lower respiratory tract infection (LRI) in infants, was presented previously. This model accounted for variable exposure to RSV over the course of the season through a force-of-infection (FOI) function modulating the overall risk of RSV infection over time. The objective of the current work was to determine whether variations in regional seasonality would impact the efficacy of a clinical trial evaluating MK-1654.

Methods

A FOI function to describe the degree of RSV exposure as a function of time was created by fitting epidemiological data to a Gaussian function added to a constant baseline value. Clinical trial simulations were conducted using the MBMA to predict seasonal incidence rates (IR) of RSV medically attended lower-respiratory tract infection (MALRI) and efficacies for a range of MK-1654 doses in both temperate and tropical regions.

Results

Epidemiological data was well captured by the FOI function. Clinical trial simulations indicated that seasonal IRs of RSV were sensitive to differences in the FOI represented by temperate and tropical regions; however, there was no substantial impact on efficacies across MK-1654 dose levels. Consistent with predictions for a temperate climate, MK-1654, when administered at the start of the RSV season in a region with a tropical climate, was also predicted to maintain high efficacy ( &gt; 75%) for the prevention of RSV MALRI for 150 days.

Conclusion

Simulations indicated that while FOI is a substantial driver of overall RSV incidence rates, MK-1654 efficacy in a late-stage clinical trial is likely to be high, regardless of regional variations in RSV.

Disclosures

Nele Plock, PhD, Certara (Employee, Shareholder)Merck & Co., Inc. (Independent Contractor) Jos Lommerse, PhD, Certara (Employee, Shareholder)Merck & Co., Inc. (Independent Contractor) Brian M. Maas, PharmD, Merck & Co., Inc. (Employee, Shareholder) Jingxian Chen, PhD, Merck & Co., Inc. (Employee, Shareholder) Francesco Bellanti, PhD, Certara (Employee, Shareholder)Merck & Co., Inc. (Independent Contractor) Li Qin, PhD, Certara (Employee, Shareholder)Merck & Co., Inc. (Independent Contractor) Han Witjes, PhD, Certara (Employee, Shareholder)Merck & Co., Inc. (Independent Contractor) Philippe Pierrillas, PhD, Certara (Employee, Shareholder)Merck & Co., Inc. (Independent Contractor) Radha Railkar, PhD, Merck & Co., Inc. (Employee, Shareholder) Antonios O. Aliprantis, MD, PhD, Merck & Co., Inc. (Employee, Shareholder) Kalpit A. Vora, PhD, Merck & Co., Inc. (Employee, Shareholder) Wei Gao, PhD, Merck & Co., Inc. (Employee, Shareholder) Luzelena Caro, PhD, Merck & Co., Inc. (Employee, Shareholder) S. Y. Amy Cheung, PhD, Certara (Employee, Shareholder) Jeffrey R. Sachs, PhD, Merck & Co., Inc. (Employee, Shareholder)

998. Forward and Reverse Translational Approaches to Predict Efficacy of the Neutralizing Respiratory Syncytial Virus (RSV) Antibody MK-1654

Background

MK-1654 is a respiratory syncytial virus (RSV) F glycoprotein neutralizing monoclonal antibody (mAb) with an extended half-life in late development to prevent RSV infection in infants. Neutralizing mAbs, like MK-1654, have great potential for prophylaxis against viral infection. However, well-validated approaches for clinical dose and efficacy predictions are lacking.

Methods

Summary-level literature data from RSV prevention studies were used in a model-based meta-analysis (MBMA) to describe the relationship between RSV incidence rates and serum neutralizing antibody (SNA) titer. The model was validated using viral challenge experiments in cotton rats and phase 3 RSV-A efficacy results in infants for an anti-RSV F mAb, REGN-2222. A phase 2b human RSV challenge study (HCS) in adults was also conducted with MK-1654. Participants (N=70) received 100, 200, 300, or 900 mg of MK-1564 or placebo and were challenged intranasally with RSV 29 days later. RSV viral load and symptomatic infection were monitored. Data from the HCS were compared to model predictions. The MBMA was used to predict efficacy of MK-1654 in a virtual population of pre- and full- term infants.

Results

The relationship between SNA titer and RSV incidence rate defined using the viral load data from the cotton rat approximated the relationship identified for infants from the clinical MBMA. The MBMA was quantitatively consistent with the phase 3 efficacy results against RSV A for REGN-2222. In the HCS, RSV nasal viral load measured by RT-qPCR and quantitative culture as well as symptomatic infections were decreased in MK-1654 recipients compared to placebo. Incidence rates of RSV infection in the HCS were also consistent with MBMA predictions. The model-based clinical trial simulations for MK-1654 indicated a high probability of substantial efficacy against RSV-associated medically attended lower respiratory tract infection ( >75% for 5 months) for doses ≥75 mg.

Conclusion

Our MBMA successfully quantified the relationship between RSV SNA and clinically relevant endpoints, including lower respiratory tract infection in infants. MBMA-based efficacy predictions support continued development of the MK-1654 antibody for the prevention of RSV in infants.

Disclosures

Brian M. Maas, PharmD, Merck & Co., Inc. (Employee, Shareholder) Jos Lommerse, PhD, Certara (Employee, Shareholder)Merck & Co., Inc. (Independent Contractor) Nele Plock, PhD, Certara (Employee, Shareholder)Merck & Co., Inc. (Independent Contractor) Radha Railkar, PhD, Merck & Co., Inc. (Employee, Shareholder) S. Y. Amy Cheung, PhD, Certara (Employee, Shareholder) Luzelena Caro, PhD, Merck & Co., Inc. (Employee, Shareholder) Jingxian Chen, PhD, Merck & Co., Inc. (Employee, Shareholder) Wen Liu, MPH, Merck & Co., Inc. (Employee, Shareholder) Ying Zhang, PhD, Merck & Co., Inc. (Employee, Shareholder) Qinlei Huang, MS, Merck & Co., Inc. (Employee, Shareholder) Wei Gao, PhD, Merck & Co., Inc. (Employee, Shareholder) Li Qin, PhD, Certara (Employee, Shareholder)Merck & Co., Inc. (Independent Contractor) Jie Meng, MSc, Certara (Employee, Shareholder)Merck & Co., Inc. (Independent Contractor) Han Witjes, PhD, Certara (Employee, Shareholder)Merck & Co., Inc. (Independent Contractor) Emilie Schindler, PhD, Certara (Employee, Shareholder)Merck & Co., Inc. (Independent Contractor) Benjamin Guiastrennec, PharmD, PhD, Certara (Employee, Shareholder)Merck & Co., Inc. (Independent Contractor) Francesco Bellanti, PhD, Certara (Employee, Shareholder)Merck & Co., Inc. (Independent Contractor) Daniel Spellman, PhD, Merck & Co., Inc. (Employee, Shareholder) Brad Roadcap, MS, Merck & Co., Inc. (Employee, Shareholder) Amy Espeseth, PhD, Merck & Co., Inc. (Employee, Shareholder) S. Aubrey Stoch, MD, Merck & Co., Inc. (Employee, Shareholder) Eseng Lai, MD, PhD, Merck & Co., Inc. (Employee, Shareholder) Kalpit A. Vora, PhD, Merck & Co., Inc. (Employee, Shareholder) Antonios O. Aliprantis, MD, PhD, Merck & Co., Inc. (Employee, Shareholder) Jeffrey R. Sachs, PhD, Merck & Co., Inc. (Employee, Shareholder)

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.e., seasonal variation) are necessary.

METHODS

Five decades of clinical trial literature were leveraged to build a model-based meta-analysis (MBMA) describing the relationship between RSV serum neutralizing activity (SNA) and clinical endpoints. The MBMA was validated by backward translation to animal challenge experiments and forward translation to predict results of a recent RSV mAb trial. MBMA predictions were evaluated against a human trial of 70 participants who received either placebo or one of four dose-levels of MK-1654 and were challenged with RSV [NCT04086472]. The MBMA was used to perform clinical trial simulations and predict efficacy of MK-1654 in the infant target population.

FINDINGS

The MBMA established a quantitative relationship between RSV SNA and clinical endpoints. This relationship was quantitatively consistent with animal model challenge experiments and results of a recently published clinical trial. Additionally, SNA elicited by increasing doses of MK-1654 in humans reduced RSV symptomatic infection rates with a quantitative relationship that approximated the MBMA. The MBMA indicated a high probability that a single dose of ≥ 75 mg of MK-1654 will result in prophylactic efficacy (> 75% for 5 months) in infants.

INTERPRETATION

An MBMA approach can predict efficacy of neutralizing antibodies against RSV and potentially other respiratory pathogens.

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. A dataset of 60 individual patients with COVID-19 with clinical viral load (VL) and reported disease severity were assembled from literature. Viral infection and replication mechanisms of SARS-CoV-2, viral-induced cell death, and time-dependent immune response are incorporated in the model to describe the dynamics of viruses and immune response. Disease severity are tested as a covariate to model parameters. The IVDM was fitted to the data and parameters were estimated using the nonlinear mixed-effect model. The model can adequately describe individual viral dynamics profiles, with disease severity identified as a covariate on infected cell death rate. The modeling suggested that it takes about 32.6 days to reach 50% of maximum cell-based immunity. Simulations based on virtual populations suggested a typical mild case reaches VL limit of detection (LOD) by 13 days with no treatment, a moderate case by 17 days, and a severe case by 41 days. Simulations were used to explore hypothetical treatments with different initiation time, disease severity, and drug effects to demonstrate the usefulness of such modeling in informing decisions. Overall, the IVDM modeling and simulation platform enables simulations for viral dynamics and treatment efficacy and can be used to aid in clinical pharmacokinetic/pharmacodynamic (PK/PD) and dose-efficacy response analysis for COVID-19 drug development.

The challenge of quantifying screening colonoscopy quality: Development and psychometric properties of the Colonoscopy Quality Score instrument

INTRODUCTION AND AIMS

Colonoscopy quality is measured by the degree in which the examination increases the likelihood of obtaining adequate results on health. Our aim was to develop an instrument for evaluating the quality of screening colonoscopies, taking into account the performance of endoscopists and endoscopy units.

MATERIALS AND METHODS

Mixed methodology was employed. The first stage (qualitative) consisted of a Medline search, from which a group of experts developed the quality score items. The second stage (quantitative) utilized a modified Delphi technique to reach consensus (3 rounds). We evaluated the psychometric properties of the instrument (reliability and construct validity) in elective screening colonoscopies (in patients≥50 years of age), performed within the January-April 2017 time frame.

RESULTS

A final instrument with 8 items was produced: 1) the Boston Bowel Preparation Scale score; 2) cecal intubation rate; 3) colonoscopy withdrawal time; 4) image documentation; 5) adenoma detection rate; 6) endoscopic surveillance planning; 7) perforation rate, and 8) continuous improvement programs. The instrument was evaluated in 323 colonoscopies performed by 31 endoscopists and found to be one-dimensional and reliable (Cronbach's alpha 0.76). Performance was compared between endoscopists (center 1) and an expert endoscopist from another center (center 2): Boston Bowel Preparation Scale score 8.3 vs. 7.36 (P<.001), cecal intubation rate 93.5 vs. 96%, colonoscopy withdrawal time 14.8 vs. 8.4min (P<.001), and adenoma detection rate 34 vs. 52.2% (P<.001), respectively.

CONCLUSION

The Colonoscopy Quality Score is a reliable and valid instrument for evaluating screening colonoscopy quality. Its results could be adapted to the usual endoscopic report to adjust monitorization frequency post-colonoscopy.

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. We evaluated the bronchopulmonary pharmacokinetic/pharmacodynamic profile of this 3 g ceftolozane/tazobactam regimen in ventilated pneumonia patients.

Methods

This was an open-label, multicentre, Phase 1 trial (clinicaltrials.gov: NCT02387372). Mechanically ventilated patients with proven/suspected pneumonia received four to six doses of 3 g of ceftolozane/tazobactam (adjusted for renal function) q8h. Serial plasma samples were collected after the first and last doses. One bronchoalveolar lavage sample per patient was collected at 1, 2, 4, 6 or 8 h after the last dose and epithelial lining fluid (ELF) drug concentrations were determined. Pharmacokinetic parameters were estimated by non-compartmental analysis and pharmacodynamic analyses were conducted to graphically evaluate achievement of target exposures (plasma and ELF ceftolozane concentrations >4 mg/L and tazobactam concentrations >1 mg/L; target in plasma: ≥30% and ≥20% of the dosing interval, respectively).

Results

Twenty-six patients received four to six doses of study drug; 22 were included in the ELF analyses. Ceftolozane and tazobactam T_max (6 and 2 h, respectively) were delayed in ELF compared with plasma (1 h). Lung penetration, expressed as the ratio of mean drug exposure (AUC) in ELF to plasma, was 50% (ceftolozane) and 62% (tazobactam). Mean ceftolozane and tazobactam ELF concentrations remained >4 mg/L and >1 mg/L, respectively, for 100% of the dosing interval. There were no deaths or adverse event-related study discontinuations.

Conclusions

In ventilated pneumonia patients, 3 g of ceftolozane/tazobactam q8h yielded ELF exposures considered adequate to cover ceftolozane/tazobactam-susceptible respiratory pathogens.

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.

METHODS

Three open-label, phase I clinical trials in healthy adults were conducted with multiple daily doses of oral GZR or EBR/GZR and single oral doses of statins. Trial 1: GZR 200 mg plus pitavastatin 10 mg. Trial 2: Part 1, GZR 200 mg plus rosuvastatin 10 mg, then EBR 50 mg/GZR 200 mg plus rosuvastatin 10 mg; Part 2, EBR 50 mg/GZR 200 mg plus pravastatin 40 mg. Trial 3: EBR 50 mg/GZR 200 mg plus atorvastatin 10 mg.

RESULTS

Neither GZR nor EBR pharmacokinetics were meaningfully affected by statins. Coadministration of EBR/GZR did not result in clinically relevant changes in the exposure of pitavastatin or pravastatin. However, EBR/GZR increased exposure to rosuvastatin (126%) and atorvastatin (94%). Coadministration of statins plus GZR or EBR/GZR was generally well tolerated.

CONCLUSIONS

Although statins do not appreciably affect EBR or GZR pharmacokinetics, EBR/GZR can impact the pharmacokinetics of certain statins, likely via inhibition of breast cancer resistance protein but not organic anion-transporting polypeptide 1B. Coadministration of EBR/GZR with pitavastatin or pravastatin does not require adjustment of either dose of statin, whereas the dose of rosuvastatin and atorvastatin should be decreased when coadministered with EBR/GZR.

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. Pharmacokinetic sampling occurred at 0 (predose), 1, 2, 4, 6, and 8 hours after the start of the infusion. Noncompartmental analyses were conducted on concentration data. The following pharmacodynamic targets were evaluated: time that free (unbound) drug concentrations exceeded the minimum inhibitory concentration (fT>MIC) of 4 μg/mL for ceftolozane and time that the unbound concentration exceeded the 1 μg/mL target threshold (fT>threshold = 1 µg/mL) for > 20% of the dosing interval for tazobactam. Safety was evaluated.

RESULTS

Mean (SD) area under the plasma concentration-time curve from 0 to infinity, clearance and volume of distribution at steady state (V_ss) were 236 (118) h*µg/mL, 10.4 (4.5) L/h and 30.8 (10.8) L, respectively, for ceftolozane; and 35.5 (18.5) h*µg/mL, 35.3 (16.5) L/h and 54.8 (20.1) L, respectively, for tazobactam. Clearance and V_ss were higher for both ceftolozane and tazobactam in patients with ARC compared with healthy individuals. The mean estimated ceftolozane fT>MIC at 4 µg/mL was 86.4%; the mean estimated tazobactam fT>threshold = 1 µg/mL was 54.9%. Treatment-emergent adverse events were mild to moderate.

CONCLUSIONS

In patients with ARC, a 3 g C/T dose met respective pharmacodynamic targets for ceftolozane and tazobactam. CLINICALTRIALS.

GOV IDENTIFIER

NCT02387372.

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. To address the large unmet medical need for most infants, we are evaluating MK-1654, a fully human RSV-neutralizing antibody with half-life extending mutations targeting site IV of the fusion protein. In this 2-part, placebo-controlled, double-blind, first-in-human study, 152 healthy adults were randomized 3:1 to receive a single dose of MK-1654 or placebo in 5 cohorts (100 or 300 mg as an intramuscular dose or 300, 1000, or 3000 mg as an intravenous dose). Safety, pharmacokinetics, antidrug antibodies, and RSV serum-neutralizing antibody titers were evaluated through 1 year. MK-1654 serum concentrations increased proportionally with dose and resulted in corresponding elevations in RSV serum-neutralizing antibody titers. The antibody displayed a half-life of 73 to 88 days and an estimated bioavailability of 69% at the 300-mg dose. The overall safety profile of MK-1654 was similar to placebo, and treatment-emergent antidrug antibodies were low (2.6%) with no associated adverse events. These data support the continued development of MK-1654 for the prevention of RSV disease in infants.

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. In the raltegravir trials, participants received a single dose of raltegravir 400 mg, a single dose of elbasvir 50 mg or grazoprevir 200 mg, and raltegravir with either elbasvir or grazoprevir. In the dolutegravir trial, participants received a single dose of dolutegravir 50 mg alone or co-administered with once-daily elbasvir 50 mg and grazoprevir 200 mg.

RESULTS

The raltegravir AUC0-∞ geometric mean ratio (GMR) (90% CI) was 1.02 (0.81-1.27) with elbasvir and 1.43 (0.89-2.30) with grazoprevir. Dolutegravir AUC0-∞ GMR (90% CI) was 1.16 (1.00-1.34) with elbasvir and grazoprevir. The elbasvir AUC0-∞ GMR (90% CI) was 0.81 (0.57-1.17) with raltegravir and 0.98 (0.93-1.04) with dolutegravir. The grazoprevir AUC0-24 GMR (90% CI) was 0.89 (0.72-1.09) with raltegravir and 0.81 (0.67-0.97) with dolutegravir.

CONCLUSIONS

Elbasvir or grazoprevir co-administered with raltegravir or dolutegravir resulted in no clinically meaningful drug-drug interactions and was generally well tolerated. These results support the assertion that no dose adjustments for elbasvir, grazoprevir, raltegravir or dolutegravir are needed for co-administration in HCV/HIV-coinfected people.

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

Aim: To evaluate the effect of SLCO1B1 genetic variants on grazoprevir pharmacokinetics and efficacy. Methods: A retrospective analysis of 1578 hepatitis C virus-infected participants from ten Phase II/III clinical trials. Results: Relative to noncarriers of the risk allele, geometric mean ratios (95% CI) of grazoprevir area under curve (AUC)_0-24 were: rs4149056 (risk allele C), one copy, 1.13 (1.06-1.21), two copies, 1.43 (1.16-1.77); and rs11045819 (risk allele A), one copy, 0.93 (0.87-1.00); two copies, 0.78 (0.61-1.00). The rs2306283 variant was not associated with grazoprevir exposure. None of the SLCO1B1 variants were associated with sustained virologic response. Conclusion: Genetic variants in SLCO1B1 were associated with modest changes in grazoprevir pharmacokinetics, but not with meaningful differences in efficacy.

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.chinadrugtrials.org.cn/ CTR20160034; Protocol PN071). Participants then received 1 tablet daily for 10 days, followed by a minimum 10-day washout, after which participants received a single dose of 2 tablets (elbasvir 100 mg/grazoprevir 200 mg). Elbasvir and grazoprevir PK were assessed following single and multiple doses. Safety and tolerability were also evaluated.

Results

Twelve participants (50% male) were enrolled in and completed the study. Following single-dose oral administration of elbasvir 50 mg/grazoprevir 100 mg or elbasvir 100 mg/grazoprevir 200 mg, the median T_max was 3–4 hrs and elimination half-life was 18 hrs (elbasvir) and 30 hrs (grazoprevir). Multiple-dose administration resulted in AUC_0–24 accumulation ratios of 1.58 (elbasvir) and 2.35 (grazoprevir). Both elbasvir 50 mg/grazoprevir 100 mg and 100 mg/200 mg regimens were generally well tolerated.

Conclusion

Single-dose administration of elbasvir 50 mg/grazoprevir 100 mg or 100 mg/200 mg and once-daily administration of elbasvir 50 mg/grazoprevir 100 mg for 10 days has been adequately characterized, with PK values within the expected range, and was generally well tolerated in healthy Chinese male and female participants.

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. Twenty-nine patients met the primary end point and, therefore, were included in the PK analyses. Hepatic vaniprevir concentrations obtained with FNA were consistent with known vaniprevir PK properties. The shape of liver FNA and CNB concentration-time profiles were comparable. In conclusion, FNA may be effective for serial tissue sampling to assess hepatic drug exposure in patients with liver disease.

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. Asian participants with chronic hepatitis C virus genotype 1 or 4 infection who received elbasvir 50 mg/grazoprevir 100 mg once daily for 12 weeks or elbasvir/grazoprevir plus ribavirin for 16 weeks were included in this analysis. The primary end point was sustained virologic response at 12 weeks after completion of therapy (SVR12).

RESULTS

Seven hundred eighty Asian participants from 15 countries were included in this analysis. SVR12 was achieved by 756/780 (96.9%) of all participants, including 748/772 (96.9%) of those who received elbasvir/grazoprevir for 12 weeks and 8/8 (100%) of those who received elbasvir/grazoprevir plus ribavirin for 16 weeks. In the genotype 1b-infected population, the SVR12 rate was 691/709 (97.5%), and there was no impact of age, high baseline viral load, or presence of cirrhosis. The most frequently reported adverse events were nasopharyngitis (8.0%), upper respiratory tract infection (5.4%), and diarrhea (5.2%). Twenty participants receiving elbasvir/grazoprevir for 12 weeks reported a total of 25 serious adverse events, and 7 (0.9%) discontinued treatment because of an adverse event.

CONCLUSION

Elbasvir/grazoprevir administered for 12 weeks is an effective and generally well-tolerated treatment option for Asian individuals with hepatitis C virus genotype 1b infection.

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. In period 2, oral doses of EBR/GZR (50 mg/100 mg) were administered once daily for 10 days. In period 3, oral doses of EVG/COB/TDF/FTC were coadministered with EBR/GZR once daily for 10 days. The pharmacokinetics of EVG/COB/TDF/FTC were not clinically meaningfully altered by concomitant EBR/GZR administration. Geometric mean ratios (90%CIs) for area under the plasma concentration-time curve from time 0 to 24 hours (AUC_0-24 ) in the presence/absence of EBR/GZR were 1.1 (1.0, 1.2) for elvitegravir; 1.1 (1.0, 1.1) for emtricitabine; 1.2 (1.1, 1.2) for tenofovir; and 1.5 (1.4, 1.6) for cobicistat. In comparison, the AUC_0-24 of elbasvir was ∼2 times higher and the AUC_0-24 of grazoprevir was ∼5 times higher following concomitant administration of EVG/COB/TDF/FTC and EBR/GZR. Geometric mean ratios (90%CI) for AUC_0-24 in the presence/absence of EVG/COB/TDF/FTC were 2.2 (2.0, 2.4) for elbasvir and 5.4 (4.5, 6.4) for grazoprevir. Coadministration of EVG/COB/TDF/FTC and EBR/GZR was generally well tolerated in healthy adults in this study. Nevertheless, because of the increased GZR exposure that occurs with coadministration of EVG/COB/TDF/FTC and EBR/GZR, coadministration of this combination is not recommended in those coinfected with HIV and HCV.

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. In the first study (N = 10), participants received TDF 300 mg once daily, elbasvir 50 mg once daily, and elbasvir coadministered with TDF. In the second study (N = 12), participants received TDF 300 mg once daily, grazoprevir 200 mg once daily, and grazoprevir coadministered with TDF. In the third study (N = 14), participants received TDF 300 mg once daily and TDF 300 mg coadministered with coformulated elbasvir/grazoprevir 50 mg/100 mg once daily. Pharmacokinetics and safety were evaluated. Following coadministration, the tenofovir area under the plasma concentration-time curve to 24 hours and maximum plasma concentration geometric mean ratios (90% confidence intervals) for tenofovir and coadministered drug(s) versus tenofovir were 1.3 (1.2, 1.5) and 1.5 (1.3, 1.6), respectively, when coadministered with elbasvir; 1.2 (1.1, 1.3) and 1.1 (1.0, 1.2), respectively, when coadministered with grazoprevir; and 1.3 (1.2, 1.4) and 1.1 (1.0, 1.4), respectively, when coadministered with the elbasvir/grazoprevir coformulation. TDF had minimal effect on elbasvir and grazoprevir pharmacokinetics. Elbasvir and/or grazoprevir coadministered with TDF resulted in no clinically meaningful tenofovir exposure increases and was generally well tolerated, with no deaths, serious adverse events (AEs), discontinuations due to AEs, or laboratory AEs reported. No dose adjustments for elbasvir/grazoprevir or TDF are needed for coadministration in HCV/HIV-coinfected people.

2381. Ceftolozane/Tazobactam in the Treatment of Experimental Pseudomonas aeruginosa Pneumonia in Persistently Neutropenic Rabbits: Impact on Strains With Genetically Defined Resistance

Background

Pseudomonas pneumonia is a life-threatening infection with high mortality, particularly in neutropenic patients. The efficacy of current antimicrobial therapy with extended spectrum penicillins (ESPs) and anti-pseudomonal cephalosporins (ASCs) is limited by emergence of resistance. Ceftolozane/tazobactam is a novel cephalosporin with in vitro activity against isolates of Pseudomonas aeruginosa that are resistant to ESPs and ASCs. In order to assess the antimicrobial effect of ceftolozane/tazobactam in treatment of Pseudomonas pneumonia, we investigated this new agent in the treatment of experimental Pseudomonas pneumonia in persistently neutropenic rabbits infected with different strains of genetically defined mechanisms of resistance.

Methods

Pseudomonas pneumonia was established in a rabbit model by direct endotracheal inoculation of P. aeruginosa 1 × 10⁸–10⁹ CFUs for tracheobronchial colonization that evolves into bronchopneumonia. Four treatment groups were studied: ceftolozane/tazobactam, ceftazidime (CTZ), piperacillin/tazobactam (TZP), and untreated controls (UC). Rabbits were dosed IV to achieve humanized doses of ceftolozane/tazobactam 3g (2g/1g) Q8h, CTZ 2g Q8h, and TZP 4.5g Q8h. Four isolates of P. aeruginosa were studied: pan-susceptible (PS), OPRD porin loss (OPRDPL), efflux pump expression (EPE), and AmpC hyperexpression (ACHE). Profound, persistent neutropenia was maintained with cytosine arabinoside and methylprednisolone. Treatment was continued for 12 days.

Results

Treatment with ceftolozane/tazobactam resulted in ≥10⁵ reduction in residual pulmonary bacterial burden caused by all 4 strains (P ≤ 0.01). This antibacterial activity coincided with reduction of lung weight (P < 0.05), which is a marker of organism-mediated pulmonary injury. CTZ was less active in ACHE-infected rabbits, while TZP had less activity in EPE, ACHE, and OPRDPL strains. Survival was prolonged in ceftolozane/tazobactam and CTZ treatment groups in comparison to that of TZP and UC (P < 0.001).

Conclusion

Ceftolozane/tazobactam is highly active in treatment of experimental P. aeruginosa pneumonia in persistently neutropenic rabbits, including infections caused by strains with the most common resistant mechanisms.

Disclosures

C. A. DeRyke, Merck: Employee, Salary. D. L. Culshaw, Merck: Employee, Salary. L. Caro, Merck: Employee and Shareholder, Salary and stock options. M. J. Satlin, Hardy Diagnostics: Grant Investigator, Research support. Allergan: Grant Investigator, Grant recipient. Merck: Grant Investigator, Grant recipient. Biomerieux: Grant Investigator, Grant recipient. Achaogen: Consultant, Consulting fee. T. J. Walsh, Merck: Grant Investigator, Research grant. Atellas: Consultant, Grant Investigator and Scientific Advisor, Consulting fee and Research grant. Gilead: Scientific Advisor, Consulting fee. Allergan: Grant Investigator and Scientific Advisor, Consulting fee and Research grant. Scynexis: Grant Investigator, Research grant. Amplyx: Grant Investigator, Research grant. Shionogi: Scientific Advisor, Consulting fee.

1971. A Randomized, Double-Blind, Placebo-Controlled Trial to Assess the Safety and Tolerability of a Respiratory Syncytial Virus (RSV) Neutralizing Monoclonal Antibody (MK-1654) in Healthy Subjects

Background

Respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract infection and hospitalization in infants. Prophylaxis for RSV infection is only recommended for the highest risk infants, leaving the majority of infants unprotected. MK-1654 is a fully human monoclonal antibody targeting the RSV fusion (F) protein with Fc domain mutations to extend half-life that is being developed to provide passive immunity against RSV in infants. The safety profile, development of anti-drug antibodies (ADAs), serum neutralizing antibody (SNA) titers, and pharmacokinetics (PK) in healthy adult volunteers receiving single-ascending doses of MK-1654 was evaluated.

Methods

In this double-blinded ongoing Phase 1 study, healthy adults of non-childbearing potential (19 to 59 years) were randomized in a 3:1 ratio to receive a single dose of MK-1654 or placebo (0.9% sodium chloride injection, USP) as a bolus intramuscular injection (IM) or in an intravenous infusion (IV) for at least 2.5 hours. Dose levels included 100 and 300 mg IM, and 300, 1,000, and 3,000 mg IV. Standard methods were used to assess safety and tolerability. Serum was tested for ADAs and RSV A SNA titers at time points up to day 120 and up to day 90, respectively. MK-1654 adult PK and estimated PK for infants will be reported separately.

Results

A total of 152 subjects (male = 117, female = 35) have been enrolled (mean age = 41 years). No deaths, serious adverse events, discontinuations due to AEs, clinically significant laboratory AEs, or dose-dependent pattern of drug-related AEs were reported. Sixty-six subjects reported 181 clinical AEs (97.8% mild and 2.2% moderate in intensity). The most common AEs (≥5%) were headache, nasal congestion, vessel puncture site hemorrhage, oropharyngeal pain, rhinorrhea and nausea. No treatment emergent ADAs have been identified through time points tested. Administration of MK-1654 resulted in a dose-dependent increase in RSV A SNA titers through Day 90 (figure). Updated safety, SNA titers and ADAs will be provided.

Conclusion

MK-1654 was generally well tolerated at doses up to 300 mg IM and up to 3,000 mg IV and resulted in a dose-dependent increase in SNA titers, reflecting biologically active MK-1654 in the serum. No treatment emergent ADAs have been observed.

Disclosures

A. Aliprantis, Merck: Employee and Shareholder, Salary and stock options. D. Wolford, Merck: Employee and Shareholder, Salary and stock options. L. Caro, Merck: Employee and Shareholder, Salary and stock options. B. Maas, Merck: Employee and Shareholder, Salary and stock options. H. Ma, Merck: Employee and Shareholder, Salary and stock options. K. Vora, Merck: Employee, Salary. D. Geng, Merck: Employee and Shareholder, Salary and stock options. R. Railkar, Merck: Employee and Shareholder, Salary and stock options. A. Lee, Merck: Employee and Shareholder, Salary and stock options. L. Sterling, Merck: Investigator, Research grant. E. Lai, Merck: Employee and Shareholder, Salary and stock options.

1384. RSV Monoclonal Antibody (MK-1654) Phase 1 Pharmacokinetics (PK) in Healthy Adults and Population PK Modeling to Support Pediatric Development

Background

Respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract infection and hospitalization in infants. MK-1654 is a monoclonal antibody (mAb) being developed to prevent RSV infection in infants and is undergoing evaluation in a Phase 1 study. Incorporation of YTE mutations extend its half-life to allow for dosing once every RSV season. Preliminary Phase 1 PK results and the development of a population PK model that characterizes adult PK to predict pediatric exposures are presented here.

Methods

In this double-blinded Phase 1 study, 152 healthy males and females of nonchildbearing potential aged 19–59 years were randomized in a 3:1 ratio to receive a single dose of MK-1654 or placebo as a bolus intramuscular injection (IM) or in an intravenous infusion (IV) over 2.5 hours. Dose levels included 100 mg IM, 300 mg IM, 300 mg IV, 1,000 mg IV and 3,000 mg IV. Serial serum samples were collected to measure MK-1654 PK via a validated LC/MS assay. A noncompartmental PK analysis was conducted using preliminary data from 60 subjects up to Day 150 (900 observations). A population PK model was developed to simultaneously characterize the IM and IV adult PK data and to predict pediatric PK through allometric scaling. Pediatric MK-1654 PK was predicted for several IM doses for a typical sized infant (35 weeks gestational age at birth; 4 months chronological age at dosing; 50th percentile weight).

Results

In adults, the median time to maximum concentration observed was ~6–10 days following IM injection. The apparent half-life of MK-1654 ranged from ~70–85 days after either IM or IV doses. The estimated IM bioavailability was ~71%. C_max and AUC_{0-90 days} increased dose proportionally following IV administration. MK-1654 adult PK was best characterized using a two-compartment model with first-order elimination. IM absorption was described using a first-order rate constant with lag time. Inter-individual variability was included for clearance (CL and Q), central volume (V2), and absorption rate (Ka). The pediatric model suggested apparent terminal half-life in a typical infant is shorter than adults, likely being driven by infant growth during treatment.

Conclusion

Predicted infant PK profiles support further development of MK-1654 in children.

Disclosures

B. Maas, Merck: Employee and Shareholder, Salary and stock options. A. Aliprantis, Merck: Employee and Shareholder, Salary and stock options. D. Wolford, Merck: Employee and Shareholder, Salary and stock options. G. Fayad, Merck: Employee and Shareholder, Salary and stock options. K. Vora, Merck: Employee, Salary. D. Geng, Merck: Employee and Shareholder, Salary and stock options. H. Ma, Merck: Employee and Shareholder, Salary and stock options. L. Caro, Merck: Employee and Shareholder, Salary and stock options.

No Pharmacokinetic Interactions Between Elbasvir or Grazoprevir and Buprenorphine/Naloxone in Healthy Participants and Participants Receiving Stable Opioid Agonist Therapy

The aims of these phase I trials were to evaluate the pharmacokinetic interaction between elbasvir (EBR) or grazoprevir (GZR) and buprenorphine/naloxone (BUP/NAL). Trial 1 was a single-dose trial in healthy participants. Trial 2 was a multiple-dose trial in participants on BUP/NAL maintenance therapy. Coadministration of EBR or GZR with BUP/NAL had minimal effect on the pharmacokinetics of BUP/NAL, EBR, and GZR. The geometric mean ratios (GMRs (90% CI)) for BUP, norbuprenorphine, and NAL AUC0-∞ were 0.98 (0.89-1.08), 0.97 (0.86-1.09), and 0.88 (0.78-1.00) in the presence/absence of EBR; 0.98 (0.81-1.19), 1.13 (0.97-1.32), and 1.10 (0.82-1.47) in the presence/absence of GZR. The GMRs (90% CI) for EBR and GZR AUC0-∞ in the absence/presence of BUP/NAL were 1.22 (0.98-1.52) and 0.86 (0.63-1.18). In conclusion, no dose adjustment for BUP/NAL, EBR, or GZR is required for patients with HCV infection receiving EBR/GZR and BUP/NAL maintenance therapy.

Pharmacokinetics, Safety, and Tolerability of Single-Dose Elbasvir in Participants with Hepatic Impairment

BACKGROUND

The combination of elbasvir and grazoprevir is approved for the treatment of hepatitis C virus genotype 1 or 4 infection.

OBJECTIVE

To evaluate the pharmacokinetics and safety of single-dose elbasvir 50 mg in participants with hepatic impairment.

METHODS

Participants with mild, moderate, or severe hepatic impairment and age-, sex-, and weight-matched healthy controls were enrolled in a 3-part, open-label, sequential-panel, single-dose pharmacokinetic study. Blood samples were collected to assess pharmacokinetics. Safety and tolerability were assessed throughout the study.

RESULTS

Thirty-four participants were enrolled: eight with mild hepatic impairment, 11 with moderate hepatic impairment, seven with severe hepatic impairment, and eight healthy matched controls. Participants with mild, moderate, and severe hepatic impairment demonstrated a numeric, but not statistically significant, decrease in elbasvir exposure compared with controls, with a mean 39, 28, and 12% decrease in area under the concentration-time curve from time 0 extrapolated to infinity, as well as a 42, 31, and 42% decrease in maximum plasma concentration (C _max), respectively. The observed median time to C _max was similar in participants with hepatic impairment and controls. Single-dose administration of elbasvir was well tolerated.

CONCLUSIONS

The pharmacokinetics of elbasvir after a single, oral 50-mg dose were not clinically meaningfully altered in non-HCV-infected participants with mild, moderate, or severe hepatic dysfunction. However, since elbasvir is currently available only as part of a fixed-dose combination with grazoprevir, the fixed-dose combination should not be administered to patients with moderate or severe hepatic impairment, due to the significantly increased plasma grazoprevir exposures in those populations.

No Pharmacokinetic Interactions Between Elbasvir or Grazoprevir and Methadone in Participants Receiving Maintenance Opioid Agonist Therapy

We conducted two phase I trials to evaluate the pharmacokinetic interactions between elbasvir (EBR), grazoprevir (GZR), and methadone (MK‐8742‐P010 and MK‐5172‐P030) in non‐hepatitis C virus (HCV)‐infected participants on methadone maintenance therapy. Coadministration of EBR or GZR with methadone had no clinically meaningful effect on EBR, GZR, or methadone pharmacokinetics. The geometric mean ratios (GMRs) for R‐ and S‐methadone AUC_0‐24 were 1.03 (90% confidence interval (CI), 0.92–1.15) and 1.09 (90% CI, 0.94–1.26) in the presence/absence of EBR; and 1.09 (90% CI, 1.02–1.17) and 1.23 (90% CI, 1.12–1.35) in the presence/absence of GZR. The GMRs for EBR and GZR AUC_0‐24 in participants receiving methadone relative to a healthy historical cohort not receiving methadone were 1.20 (90% CI, 0.94–1.53) and 1.03 (90% CI, 0.76–1.41), respectively. These results indicate that no dose adjustment is required for individuals with HCV infection receiving stable methadone therapy and the EBR/GZR fixed‐dose regimen.

Safety, Tolerability, and Pharmacokinetics of 3 g of Ceftolozane/Tazobactam in Healthy Adults: A Randomized, Placebo-Controlled, Multiple-Dose Study

Ceftolozane/tazobactam is an antibacterial approved at 1.5 g (1g/0.5 g) every 8 hours (q8h); higher doses may provide additional benefits in difficult-to-treat infections. We conducted a phase I trial in healthy adults evaluating safety, tolerability, and pharmacokinetics of 3 g (2 g/1 g) ceftolozane/tazobactam administered q8h for 10 days. Sixteen participants were randomized (2:1:1) to 3 g ceftolozane/tazobactam, 1.5 g ceftolozane/tazobactam, or placebo. Participants underwent regular safety and plasma drug level assessments, with a follow-up safety visit 7 days after completion. No adverse events (AEs) were reported with placebo; 75% of participants in the 1.5-g and 50% in the 3-g arm experienced AEs. AE types were similar between the ceftolozane/tazobactam groups; all AEs were mild. No participants experienced clinically meaningful laboratory assessment or electrocardiogram abnormalities. Both ceftolozane and tazobactam exhibited dose-proportional pharmacokinetics without accumulation and without substantial differences in clearance and volume of distribution between groups. In the 3-g group, mean ceftolozane parameters were: peak concentration 104 μg/mL (day 1), 112 μg/mL (day 10); half-life 3 hours (day 10); area under the concentration-time curve (AUC_(0-t) ) 272 μg·h/mL (day 1), 300μg·h/mL (day 10). Mean tazobactam parameters were: peak concentration 28 μg/mL (day 1), 26 μg/mL (day 10); half-life 1 hour (day 10); AUC_(0-t) 47μg·h/mL (day 1), 41μg·h/mL (day 10). Administration of 3 g ceftolozane/tazobactam q8h for 10 days was safe and well tolerated in healthy volunteers.

Concomitant proton pump inhibitor use does not reduce the efficacy of elbasvir/grazoprevir: A pooled analysis of 1,322 patients with hepatitis C infection

Concomitant proton pump inhibitor (PPI) use reduces plasma concentrations of certain nonstructural protein 5A inhibitors, which are key components of modern hepatitis C infection (HCV) treatments. These reduced concentrations may decrease efficacy, leading to challenging treatment failures due to the development of resistance‐associated substitutions. This post‐hoc analysis assessed 12‐week sustained viral response (SVR12) and pharmacokinetics of fixed‐dose combination elbasvir/grazoprevir (EBR/GZR) in patients with HCV infection and self‐reported PPI use. Data were derived from six phase 3 EBR/GZR trials with treatment‐naive or treatment‐experienced genotype 1‐ or 4‐infected patients, with or without compensated cirrhosis. Baseline PPI use was defined as ≥7 consecutive days of use between study days –7 and 7. Bivariate analyses assessed PPI use and factors associated with SVR12 with sex, age (continuous and dichotomous), cirrhosis status, prior treatment status, baseline HCV RNA (continuous and dichotomous), HCV genotype, and baseline resistance‐associated substitutions as variables in the models. Overall, 12% (162/1,322) of EBR/GZR‐treated patients reported baseline PPI use. Of those, 96% achieved SVR12. In patients without PPI use, 97% achieved SVR12. PPI use was not a predictive factor in achieving SVR12 based on a univariate analysis (P = 0.188). In the bivariate models, none of the interaction terms involving PPI use were statistically significant. There was no significant effect of PPI usage, regardless of adjustment for considered factors. The estimated area under the curve and maximum concentration values for EBR were comparable among patients with and without reported PPI use. Conclusion: These results demonstrate that PPI use with EBR/GZR had no clinically significant effect on SVR12 rates in genotype 1/4‐infected patients with or without compensated cirrhosis. (clinicaltrials.gov identifiers: NCT02092350, NCT02105467, NCT02105662, NCT02105688, NCT02105701, NCT02358044) (Hepatology Communications 2017;1:757–764)

Single-Dose and Multiple-Dose Pharmacokinetics of Vaniprevir in Healthy Men

Vaniprevir is an inhibitor of the hepatitis C virus (HCV) NS3/4A protease. The aim of these double‐blind, placebo‐controlled phase I studies was to evaluate the safety and pharmacokinetics of vaniprevir in healthy male volunteers. The primary objective for both studies was the safety and tolerability of vaniprevir. Single‐dose and steady‐state pharmacokinetics were also assessed. In both studies, there was no apparent relationship between the frequency or intensity of adverse events and vaniprevir dose. At single doses >20 mg, the plasma area under the curve (AUC)_0–∞ and maximum concentration (C_max) increased in a greater‐than‐dose‐proportional manner. The geometric mean ratios (GMRs; fed/fasted) were 1.22 and 0.79 for AUC_0–∞ and C_max, respectively. Following multiple doses, GMR accumulations for AUC_0–12h and C_max (day 14/day 1) ranged from 1.53 to 1.90 and from 1.41 to 1.92, respectively. These data support the use of vaniprevir with peginterferon and ribavirin in patients with HCV infection.

No Pharmacokinetic Interaction Between the Hepatitis C Virus Inhibitors Elbasvir/Grazoprevir and Famotidine or Pantoprazole

Use of agents to suppress gastric acid secretion is common among patients with hepatitis C virus (HCV) infection. The aims of this open‐label, three‐period, fixed‐sequence study were to evaluate the effect of famotidine and pantoprazole on the pharmacokinetics and safety of elbasvir/grazoprevir fixed‐dose combination (FDC) in 16 healthy subjects. Elbasvir and grazoprevir each exhibited similar pharmacokinetics following single‐dose administration of elbasvir/grazoprevir with or without famotidine or pantoprazole. Geometric mean ratios (GMRs) of grazoprevir AUC(0,∞), C_max, and C₂₄ (elbasvir/grazoprevir + famotidine or elbasvir/grazoprevir + pantoprazole vs. elbasvir/grazoprevir) ranged from 0.89–1.17. Similarly, GMRs of elbasvir AUC(0,∞), C_max, and C₂₄ (elbasvir/grazoprevir + famotidine or elbasvir/grazoprevir + pantoprazole vs. elbasvir/grazoprevir) ranged from 1.02–1.11. These results indicate that gastric acid‐reducing agents do not modify the pharmacokinetics of elbasvir or grazoprevir in a clinically relevant manner and may be coadministered with elbasvir/grazoprevir in HCV‐infected patients without restriction.

Development of an E-learning System for the Endoscopic Diagnosis of Early Gastric Cancer: An International Multicenter Randomized Controlled Trial

Background

In many countries, gastric cancer is not diagnosed until an advanced stage. An Internet-based e-learning system to improve the ability of endoscopists to diagnose gastric cancer at an early stage was developed and was evaluated for its effectiveness.

Methods

The study was designed as a randomized controlled trial. After receiving a pre-test, participants were randomly allocated to either an e-learning or non-e-learning group. Only those in the e-learning group gained access to the e-learning system. Two months after the pre-test, both groups received a post-test. The primary endpoint was the difference between the two groups regarding the rate of improvement of their test results.

Findings

515 endoscopists from 35 countries were assessed for eligibility, and 332 were enrolled in the study, with 166 allocated to each group. Of these, 151 participants in the e-learning group and 144 in the non-e-learning group were included in the analysis. The mean improvement rate (standard deviation) in the e-learning and non-e-learning groups was 1·24 (0·26) and 1·00 (0·16), respectively (P < 0·001).

Interpretation

This global study clearly demonstrated the efficacy of an e-learning system to expand knowledge and provide invaluable experience regarding the endoscopic detection of early gastric cancer (R000012039).

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This report establishes that an e-learning system on the Internet can improve the diagnostic ability of endoscopists.

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Countless endoscopists worldwide can access the system to learn how to make an endoscopic diagnosis of early gastric cancer.

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The e-learning system could be modified to provide education regarding endoscopic diagnosis in other organs.

This is the first report to demonstrate how an e-learning system based on the Internet can improve the diagnostic ability of gastrointestinal endoscopists worldwide. There is no limit to the number of endoscopists who can access the system and benefit from this opportunity to learn how to make an endoscopic diagnosis of early gastric cancer. This e-learning system could be modified to provide education regarding endoscopic diagnosis in other organs such as the large intestine and the esophagus, as well as the stomach. It may contribute to human welfare and health by reducing the mortality from gastrointestinal cancer.

Pitavastatin is a more sensitive and selective organic anion-transporting polypeptide 1B clinical probe than rosuvastatin

AIMS

Rosuvastatin and pitavastatin have been proposed as probe substrates for the organic anion-transporting polypeptide (OATP) 1B, but clinical data on their relative sensitivity and selectivity to OATP1B inhibitors are lacking. A clinical study was therefore conducted to determine their relative suitability as OATP1B probes using single oral (PO) and intravenous (IV) doses of the OATP1B inhibitor rifampicin, accompanied by a comprehensive in vitro assessment of rifampicin inhibitory potential on statin transporters.

METHODS

The clinical study comprised of two separate panels of eight healthy subjects. In each panel, subjects were randomized to receive a single oral dose of rosuvastatin (5 mg) or pitavastatin (1 mg) administered alone, concomitantly with rifampicin (600 mg) PO or IV. The in vitro transporter studies were performed using hepatocytes and recombinant expression systems.

RESULTS

Rifampicin markedly increased exposures of both statins, with greater differential increases after PO vs. IV rifampicin only for rosuvastatin. The magnitudes of the increases in area under the plasma concentration-time curve were 5.7- and 7.6-fold for pitavastatin and 4.4- and 3.3-fold for rosuvastatin, after PO and IV rifampicin, respectively. In vitro studies showed that rifampicin was an inhibitor of OATP1B1 and OATP1B3, breast cancer resistance protein and multidrug resistance protein 2, but not of organic anion transporter 3.

CONCLUSIONS

The results indicate that pitavastatin is a more sensitive and selective and thus preferred clinical OATP1B probe substrate than rosuvastatin, and that a single IV dose of rifampicin is a more selective OATP1B inhibitor than a PO dose.

Liver-to-plasma vaniprevir (MK-7009) concentration ratios in HCV-infected patients

BACKGROUND

Some drugs that are actively taken up into the liver exhibit greater than dose proportional increases in plasma exposure, although human liver-to-plasma concentration ratios have rarely been evaluated. Understanding these relationships has implications for drug concentrations at the target site for certain classes of compounds, such as direct-acting antivirals, targeted towards HCV.

METHODS

Treatment-experienced, chronic HCV non-cirrhotic patients (n=3) received vaniprevir (600 mg or 300 mg twice daily) on days 1-3 and (600 mg or 300 mg single dose) on day 4. Core needle biopsy was performed at 6 or 12 h post-dose on day 4. Blood samples were collected pre-dose on days 1 and 4, and for 24 h post-dose on day 4. The primary study objective was the hepatic concentration of vaniprevir at 6 and 12 h post-dose.

RESULTS

Vaniprevir plasma pharmacokinetic parameters increased in a greater than dose-proportional manner between the 300 mg and 600 mg doses, with approximately fivefold increases in AUC0-12 and Cmax associated with a twofold increase in dose (AUC0-12, 10.6 μM/h to 59.5 μM/h; Cmax, 2.60 μM to 13.5 μM). In the 300 mg and 600 mg dose groups, mean liver concentrations of vaniprevir were 84.6 μM and 169 μM at 6 h post-dose, and 29.4 μM and 53.7 μM at 12 h post-dose. Liver concentrations were higher than plasma with liver-to-plasma concentration ratios of approximately 20-280.

CONCLUSIONS

These data confirm higher vaniprevir concentrations in human liver compared with plasma and demonstrate that measurement of human liver drug concentration using needle biopsy is feasible.

Virologic resistance analysis from a phase 2 study of MK-5172 combined with pegylated interferon/ribavirin in treatment-naive patients with hepatitis C virus genotype 1 infection

BACKGROUND

Virologic failure following treatment of hepatitis C virus (HCV) genotype 1 with direct-acting antiviral agents is often accompanied by the emergence of resistant variants. MK-5172 is an investigational once-daily protease inhibitor. We analyzed variants in treatment-naive noncirrhotic patients with virologic failure on MK-5172 (100-800 mg/day) plus pegylated interferon alfa/ribavirin (peg-IFN/RBV) during a phase 2 trial.

METHODS

Population and selective clonal sequencing were performed at baseline and at virologic failure in the 4 MK-5172 dosing arms. MK-5172 activity was determined using a mutant replicon assay.

RESULTS

Six of 266 (2.3%) MK-5172 recipients satisfied prespecified criteria for virologic failure, all with genotype 1a infection. Five patients with virologic failure were in the MK-5172 100-mg arm, including 4 patients with low plasma MK-5172 levels documented during triple therapy. Variants associated with >4-fold loss of potency were detected in 3 of the 4 patients with genotype 1a breakthrough while on MK-5172. The fifth patient had undetectable HCV-RNA levels at the end of triple therapy but subsequently broke through during the peg-IFN/RBV tail 16 weeks after completion of MK-5172. Three patients had D168 variants at virologic failure, including 2 with the D168A variant associated with a 95-fold loss of potency. The sole apparent relapse was actually a genotype 3a reinfection in the MK-5172 200-mg group.

CONCLUSIONS

Virologic failure occurred uncommonly (6/266 [2.3%]) in MK-5172/peg-IFN/RBV recipients. The most prevalent treatment-emergent variants were detected at the D168 locus. D168A variants conferring approximately 2-log reduction in MK-5172 susceptibility emerged in 2 of the 4 evaluable patients with genotype 1a breakthrough. Clinical Trials Registration. NCT01353911.

The combination of MK-5172, peginterferon, and ribavirin is effective in treatment-naive patients with hepatitis C virus genotype 1 infection without cirrhosis

BACKGROUND & AIMS

MK-5172 is an inhibitor of the hepatitis C virus (HCV) nonstructural protein 3/4A protease; MK-5172 is taken once daily and has a higher potency and barrier to resistance than licensed protease inhibitors. We investigated the efficacy and tolerability of MK-5172 with peginterferon and ribavirin (PR) in treatment-naive patients with chronic HCV genotype 1 infection without cirrhosis.

METHODS

We performed a multicenter, double-blind, randomized, active-controlled, dose-ranging, response-guided therapy study. A total of 332 patients received MK-5172 (100, 200, 400, or 800 mg) once daily for 12 weeks in combination with PR. Patients in the MK-5172 groups received PR for an additional 12 or 36 weeks, based on response at week 4. Patients in the control group (n = 66) received a combination of boceprevir and PR, dosed in accordance with boceprevir's US product circular.

RESULTS

At 24 weeks after the end of therapy, sustained virologic responses were achieved in 89%, 93%, 91%, and 86% of the patients in the groups given the combination of PR and MK-5172 (100, 200, 400, or 800 mg), respectively, vs 61% of controls. In the MK-5172 group receiving 100 mg, 91% of patients had undetectable levels of HCV RNA at week 4 and qualified for the short duration of therapy. The combination of MK-5172 and PR generally was well tolerated. Transient increases in transaminase levels were noted in the MK-5172 groups given 400 and 800 mg, at higher frequencies than in the MK-5172 groups given 100 or 200 mg, or control groups.

CONCLUSIONS

Once-daily MK-5172 (100 mg) with PR for 24 or 48 weeks was highly effective and well tolerated among treatment-naive patients with HCV genotype 1 infection without cirrhosis. Studies are underway to evaluate interferon-free MK-5172-based regimens. ClinicalTrials.gov number: NCT01353911.

Vaniprevir with pegylated interferon alpha-2a and ribavirin in treatment-naïve patients with chronic hepatitis C: a randomized phase II study

Vaniprevir (MK-7009) is a macrocyclic hepatitis C virus (HCV) nonstructural protein 3/4A protease inhibitor. The aim of the present phase II study was to examine virologic response rates with vaniprevir in combination with pegylated interferon alpha-2a (Peg-IFN-α-2a) plus ribavirin (RBV). In this double-blind, placebo-controlled, dose-ranging study, treatment-naïve patients with HCV genotype 1 infection (n = 94) were randomized to receive open-label Peg-IFN-α-2a (180 μg/week) and RBV (1,000-1,200 mg/day) in combination with blinded placebo or vaniprevir (300 mg twice-daily [BID], 600 mg BID, 600 mg once-daily [QD], or 800 mg QD) for 28 days, then open-label Peg-IFN-α-2a and RBV for an additional 44 weeks. The primary efficacy endpoint was rapid viral response (RVR), defined as undetectable plasma HCV RNA at week 4. Across all doses, vaniprevir was associated with a rapid two-phase decline in viral load, with HCV RNA levels approximately 3 log(10) IU/mL lower in vaniprevir-treated patients, compared to placebo recipients. Rates of RVR were significantly higher in each of the vaniprevir dose groups, compared to the control regimen (68.8%-83.3% versus 5.6%; P < 0.001 for all comparisons). There were numerically higher, but not statistically significant, early and sustained virologic response rates with vaniprevir, as compared to placebo. Resistance profile was predictable, with variants at R155 and D168 detected in a small number of patients. No relationship between interleukin-28B genotype and treatment outcomes was demonstrated in this study. The incidence of adverse events was generally comparable between vaniprevir and placebo recipients; however, vomiting appeared to be more common at higher vaniprevir doses.

CONCLUSION

Vaniprevir is a potent HCV protease inhibitor with a predictable resistance profile and favorable safety profile that is suitable for QD or BID administration.

(1aR,5aR)1a,3,5,5a-Tetrahydro-1H-2,3-diaza-cyclopropa[a]pentalene-4-carboxylic acid (MK-1903): a potent GPR109a agonist that lowers free fatty acids in humans

G-protein coupled receptor (GPCR) GPR109a is a molecular target for nicotinic acid and is expressed in adipocytes, spleen, and immune cells. Nicotinic acid has long been used for the treatment of dyslipidemia due to its capacity to positively affect serum lipids to a greater extent than other currently marketed drugs. We report a series of tricyclic pyrazole carboxylic acids that are potent and selective agonists of GPR109a. Compound R,R-19a (MK-1903) was advanced through preclinical studies, was well tolerated, and presented no apparent safety concerns. Compound R,R-19a was advanced into a phase 1 clinical trial and produced a robust decrease in plasma free fatty acids. On the basis of these results, R,R-19a was evaluated in a phase 2 study in humans. Because R,R-19a produced only a weak effect on serum lipids as compared with niacin, we conclude that the beneficial effects of niacin are most likely the result of an undefined GPR109a independent pathway.

Prevalence of sexual and physical abuse in patients with obstructed defecation: impact on biofeedback treatment

BACKGROUND

obstructed defecation is one of the most common subtypes of constipation, and it is frequently responsive to biofeedback treatment.

AIMS

since a history of sexual and physical abuse may be present in patients with obstructed defecation, we assessed the incidence of abuse history in patients with obstructed defecation referred to a general gastroenterology practice, and whether such a history may lead to a different outcome of biofeedback training in these patients.

PATIENTS AND METHODS

one hundred and twenty-one patients (17 men, 104 women, age 53 +/- 15 years) with obstructed defecation were studied by retrospective chart review. Their history of sexual, physical and psychological abuse was obtained by a standard interview, and biofeedback training was carried out by means of a three-balloon technique.

RESULTS

a history of sexual/physical or psychological abuse was present in 12.4% patients. Biofeedback training yielded a successful improvement of obstructed defecation in 93% patients without abuse and in 100% of patients with abuse; this difference was not statistically different (p = 0.53).

CONCLUSIONS

the prevalence of sexual/physical or psychological abuse in a population of patients with obstructed defecation referred to a general gastroenterology practice is relatively low; such a history seems not to affect the outcome of biofeedback training in these patients.