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Coproporphyrins (CP‐I and CP‐III) in plasma are considered potential markers for assessing liver organic anion‐transporting polypeptide transporter OATP1B activity and monitoring OATP1B‐mediated drug‐drug interactions (DDIs) in clinical settings. However, the effect of altered renal clearance (CLrenal) on CP‐I and CP‐III plasma exposure has rarely been examined. Therefore, the purpose of this study is to further evaluate CP‐I and CP‐III as clinical endogenous markers for OATP1B activity and to investigate the impact of CLrenal on DDI assessments for the first time. In this study, 18 healthy participants were recruited to receive RO7049389 (a potential inhibitor of OATP1B) 800 mg twice daily for 6 days and a single dose of pitavastatin (a probe drug of OATP1B) before and after RO7049389 treatment. Plasma concentrations of pitavastatin, CP I, CP III, and the amounts of CP‐I and CP‐III excreted in urine were measured. Seventeen healthy participants completed the study. After multiple doses of RO7049389, the area under the plasma concentration–time curve from time 0 to 12 hours of pitavastatin increased 1.95‐fold (90% confidence interval [CI], 1.58‐2.41), while for CP‐I and CP‐III it increased 3.00‐fold (90%CI, 2.35‐3.82) and 2.84‐fold (90%CI, 2.22‐3.65), respectively. Concurrently, the CLrenal of CP‐I decreased by 31% (90%CI, 23%‐39%), and that of CP‐III decreased by 70% (90%CI, 61%‐77%). In conclusion, CP‐I and CP‐III in plasma display the potential to be applied as endogenous markers for the evaluation of OATP1B inhibition in clinical trials. While renal transporters contribute significantly to the CLrenal of CP‐III, it would be better to investigate the impact of the CLrenal on plasma exposure of CP‐III during clinical DDI assessments. [ABSTRACT FROM AUTHOR]

The objectives of this phase I study are to assess the safety, tolerability, and pharmacokinetics (PKs) of RO7049389 in healthy Chinese volunteers (HVs) and evaluate potential ethnic differences in the safety and PKs using data from this study and the first‐in‐human study (in which most of the HVs were non‐Asian). HVs randomly received a single dose of 200–600 mg of RO7049389 or a placebo in a single ascending dose (n = 28) or multiple doses of 200–400 mg of RO7049389 or a placebo in multiple ascending doses (n = 24). Safety and tolerability were monitored throughout the study. Serial blood samples were collected for PK analysis. RO7049389 was safe and well‐tolerated in the HVs. The time to maximum concentration ranged from 1.5 to 3.0 h, and terminal half‐life ranged from 3.66 to 14.6 h. A single dose of 200–600 mg and multiple doses of 200–400 mg exhibited nonlinear PKs. In general, the safety profiles were comparable between non‐Asian and Asian HVs, but the plasma exposure of RO7049389 in Chinese HVs was higher than that in non‐Asian HVs. The data generated from this study will provide guidance for future clinical studies on RO7049389 in Chinese/Asian patients with hepatitis B virus. [ABSTRACT FROM AUTHOR]

Hepatitis B virus RNA (HBV RNA)–containing particles are encapsidated pre‐genomic RNA (pgRNA) detectable in chronically infected patients in addition to virions (HBV DNA) that have been suggested as a marker of the treatment efficacy. This makes promising the use of core protein allosteric modulators, such as RG7907, which disrupt the nucleocapsid assembly and profoundly reduce HBV RNA. Here, we developed a multiscale model of HBV extending the standard viral dynamic models to analyse the kinetics of HBV DNA and HBV RNA in 35 patients treated with RG7907 for 28 days. We compare the predictions with those obtained in patients treated with the nucleotide analog tenofovir. RG7907 blocked 99.3% of pgRNA encapsidation (range: 92.1%–99.9%) which led to a decline of both HBV DNA and HBV RNA. As a consequence of its mode of action, the first phase of decline of HBV RNA was rapid, uncovering the clearance of viral particles with half‐life of 45 min. In contrast, HBV DNA decline was predicted to be less rapid, due to the continuous secretion of already formed viral capsids (t1/2 = 17 ± 6 h). After few days, both markers declined at the same rate, which was attributed to the loss of infected cells (t1/2 ≅ 6 ± 0.8 days). By blocking efficiently RNA reverse transcription but not its encapsidation, nucleotide analog in contrast was predicted to lead to a transient accumulation of HBV RNA both intracellularly and extracellularly. The model brings a conceptual framework for understanding the differences between HBV DNA and HBV RNA dynamics. Integration of HBV RNA in viral dynamic models may be helpful to better quantify the treatment effect, especially in viral‐suppressed patients where HBV DNA is no longer detectable. [ABSTRACT FROM AUTHOR]

Background and Aim Chronic hepatitis C virus (HCV) infection is the leading cause of liver diseases including cirrhosis and hepatocellular carcinoma. In China, it is a major national health problem that demands nationwide coordinated emphasis on prevention and treatment. To inform these initiatives, a nationwide survey was conducted from January to April 2015 to evaluate the knowledge, awareness, and perceived obstacles to HCV care. Methods A sample of 1000 HCV specialists across mainland China were recruited. Respondents were asked a series of 30 open-ended single or multiple response and Likert-scale questions about their HCV treatment knowledge, experience, assessment of HCV care status in China, and perceptions about treatment barriers. Results Sixty percent of the respondents answered incorrectly to more than half of the questions on basic HCV treatment principles. Over half of them incorrectly believed that maintenance therapy should be prescribed for non-responders (72%) and longer treatment duration improved sustained viral response rates (62%), regardless of HCV RNA level changes. Sixty-six percent of them believed that HCV treatment would still be interferon-based therapy in the next 5 years in China. Patient-related barriers, in particular lack of disease awareness, were considered to be the most significant barriers to HCV care. Payer and medical-provider barriers included affordability issues, lack of reimbursement coverage for testing and treatments, and lack of referral to HCV specialists. Conclusions Focused and intense patient and provider education should be carried out to increase awareness. More effective direct-acting antivirals should be made available and affordable in China. [ABSTRACT FROM AUTHOR]