Faculty Bibliography

BACKGROUND: GS-9620 is a potent oral agonist of toll-like receptor 7, a key modulator of the innate immune response. In healthy volunteers, low doses of GS-9620 (2, 4 and 6 mg) induced significant expression of peripheral interferon-stimulated-gene (ISG) mRNA in the absence of detectable serum interferon-alpha and systemic adverse events (AEs). We evaluated the safety, pharmacokinetics and pharmacodynamics of GS-9620 in treatment-naive patients chronically infected with HCV genotype 1. METHODS: In this double-blind, placebo-controlled study, 51 patients were randomized 5:1 (active:placebo) to receive either a single dose or two once-weekly doses of GS-9620 at four dose levels (0.3, 1, 2 and 4 mg) or placebo. Pharmacodynamic assessments included peripheral ISG15 mRNA expression, serum interferon-alpha and interferon-gamma-inducible protein (IP)-10 levels and HCV RNA quantification. RESULTS: GS-9620 was well-tolerated at all doses. Most AEs were mild or moderate in severity. GS-9620 exhibited dose-linear pharmacokinetics with a median half-life in plasma of 18 h. Transient, dose-dependent ISG15 induction was observed at 1, 2 and 4 mg, with peak mean fold change within 48 h followed by a decline to baseline levels within 7 days of dosing. Serum interferon-alpha induction post-baseline was detected in 16.7% (8/48) of patients. No clinically significant reductions in HCV RNA were observed. CONCLUSIONS: GS-9620 was safe, well-tolerated and biologically active in patients with HCV infection. Induction of ISG15 occurred in the absence of detectable serum interferon-alpha or systemic AEs in most patients, supporting a pre-systemic mechanism of action. ClinicalTrials.gov identifier: NCT01591668.

BACKGROUND: Sofosbuvir is a chain-terminating nucleotide analogue inhibitor of the hepatitis C virus (HCV) NS5B RNA polymerase that is efficacious in subjects with HCV genotype 1-6 infection. Sofosbuvir resistance is primarily conferred by the S282T substitution in NS5B. METHODS: NS5B sequencing and susceptibility testing of HCV from subjects infected with genotypes 1-6 who participated in phase 2 and 3 sofosbuvir clinical trials was performed. RESULTS: No NS5B variants present at baseline among 1645 sofosbuvir-treated subjects were associated with treatment failure; sofosbuvir susceptibility was within 2-fold of reference. Among 282 subjects who did not achieve sustained virologic response, no novel sofosbuvir resistance-associated variants were identified, and the NS5B changes observed did not confer significant reductions in sofosbuvir susceptibility. In 1 subject with S282T observed at relapse 4 weeks after sofosbuvir monotherapy, the resistant variant (13.5-fold reduced sofosbuvir susceptibility, replication capacity <2% of control) became undetectable by deep sequencing 12 weeks after treatment. L159F and V321A were identified as treatment-emergent variants but did not confer resistance to sofosbuvir in the replicon system. CONCLUSIONS: These data demonstrate a uniform susceptibility of subject-derived HCV to sofosbuvir, and also show that selection of sofosbuvir-resistant HCV is exceedingly rare and is associated with a significant reduction in viral fitness.

UNLABELLED: Understanding hepatitis C virus (HCV) replication has been limited by access to serial samples of liver, the primary site of viral replication. Our understanding of how HCV replicates and develops drug-resistant variants in the liver is limited. We studied 15 patients chronically infected with genotype 1 HCV treated with telaprevir (TVR)/pegylated-interferon alpha/ribavirin. Hepatic fine needle aspiration was performed before treatment and at hour 10, days 4 and 15, and week 8 after initiation of antiviral therapy. We measured viral kinetics, resistance patterns, TVR concentrations, and host transcription profiles. All patients completed all protocol-defined procedures that were generally well tolerated. First-phase HCV decline (baseline/treatment day 4) was significantly slower in liver than in plasma (slope plasma: -0.29; liver, -0.009; P < 0.001), whereas second-phase decline (posttreatment days 4-15) did not differ between the two body compartments (-0.11 and -0.15, respectively; P = 0.1). TVR-resistant variants were detected in plasma, but not in liver (where only wild-type virus was detected). Based upon nonstructural protein 3 sequence analysis, no compartmentalization of viral populations was observed between plasma and liver compartments. Gene expression profiling revealed strong tissue-specific expression signatures. Human intrahepatic TVR concentration, measured for the first time, was lower, compared to plasma, on a gram per milliliter basis. We found moderate heterogeneity between HCV RNA levels from different intrahepatic sites, indicating differences in hepatic microenvironments. CONCLUSION: These data support an integrated model for HCV replication wherein the host hepatic milieu and innate immunity control the level of viral replication, and the early antiviral response observed in the plasma is predominantly driven by inhibition of hepatic high-level HCV replication sites.

BACKGROUND & AIMS: Peginterferon lambda-1a (Lambda) is a type-III interferon with similar antiviral activity to alfa interferons but with a diminished extrahepatic receptor distribution, reducing the risk for extrahepatic adverse events. METHODS: This was a randomized, blinded, actively-controlled, multicentre phase 2b dose-ranging study in patients chronically infected with HCV genotypes 1-4. Treatment-naive patients received Lambda (120/180/240 mug) or peginterferon alfa-2a (alfa; 180 mug) once-weekly with ribavirin for 24 (genotypes [GT] 2,3) or 48 (GT1,4) weeks. RESULTS: Rates of undetectable HCV-RNA at week 12 (complete early virologic response [cEVR]; primary end point) were significantly higher in GT1,4 patients receiving Lambda vs. alfa (170/304, 56% vs. 38/103, 37%); with similar cEVR rates for GT2,3 (80/88, 91% vs. 26/30, 87%). Rates of undetectable HCV-RNA at week 4 were significantly higher on 180 mug (15/102, 15% GT1,4; 22/29, 76% GT2,3) and 240 mug (17/104, 16% GT1,4; 20/30, 67% GT2,3) Lambda than alfa (6/103, 6% GT1,4; 9/30, 30% GT2,3). Sustained virologic responses (post-treatment week 24) were comparable between Lambda and alfa for GT1,4 (37-46% Lambda; 37% alfa) and GT2,3 (60-76% Lambda; 53% alfa). Aminotransferase and/or bilirubin elevations were the primary dose-limiting abnormalities for Lambda; a sponsor-mandated 240 to 180 mug dose reduction was therefore implemented. Serious adverse events were comparable (3-13% Lambda; 3-7% alfa). Grade 3-4 haemoglobin, neutrophil, and platelet reductions were lower on Lambda than alfa. Among alfa patients, 28/133 (21%) had peginterferon and 31/133 (23%) had ribavirin dose reductions for haematologic abnormalities vs. 0/392 and 8/392 (2%) on Lambda. Lambda demonstrated fewer musculoskeletal (16-28% vs. 47-63%) and influenza-like events (8-23% vs. 40-46%) than alfa. CONCLUSION: Lambda was associated with improved or similar rates of virologic response with fewer extrahepatic adverse events than alfa in chronic HCV infection.

BACKGROUND: Interferon-free regimens are needed to treat hepatitis C virus (HCV) infections. We investigated the efficacy of combined simeprevir and sofosbuvir. METHODS: We enrolled patients with chronic HCV genotype 1 infections who had previously not responded to pegylated interferon (peginterferon) and ribavirin or were treatment naive. Patients were randomly assigned in a 2:1:2:1 ratio to receive 150 mg simeprevir and 400 mg sofosbuvir daily for 24 weeks with (group 1) or without (group 2) ribavirin or for 12 weeks with (group 3) or without (group 4) ribavirin, in two cohorts: previous non-responders with METAVIR scores F0-F2 (cohort 1) and previous non-responders and treatment-naive patients with METAVIR scores F3-F4 (cohort 2). The primary endpoint was sustained virological response 12 weeks after stopping treatment (SVR12). Analysis was done by intention to treat. Safety data from cohorts 1 and 2 were pooled for analysis. This study is registered with ClinicalTrials.gov, number NCT01466790. FINDINGS: 168 patients were enrolled and randomised, and 167 started treatment (n=80 in cohort 1 and n=87 in cohort 2). SVR12 was achieved in 154 (92%) patients (n=72 [90%, 95% CI 81-96] in cohort 1 and n=82 [94%, 87-98] in cohort 2). The most common adverse events in the pooled groups were fatigue (n=52 [31%]), headache (n=33 [20%]), and nausea (n=26 [16%]). Grade 4 adverse events were seen in one (2%) of 54 patients in each of groups 1 and 3 and in three (10%) of 31 patients in group 2, whereas grade 3-4 events were reported in less than 5% of all patients, except increased blood amylase concentration. Serious adverse events were seen in four (2%) patients, all in groups 1 and 2. Four (2%) patients discontinued all study treatment because of adverse events, three before week 12. INTERPRETATION: Combined simeprevir and sofosbuvir was efficacious and well tolerated. FUNDING: Janssen.

BACKGROUND: An unmet need exists for interferon-free and ribavirin-free treatments for chronic hepatitis C virus (HCV) infection. In this study, we assessed all-oral therapy with daclatasvir (NS5A replication complex inhibitor) plus asunaprevir (NS3 protease inhibitor) in patients with genotype 1b infection, including those with high unmet needs or cirrhosis, or both. METHODS: We did this phase 3, multicohort study (HALLMARK-DUAL) at 116 sites in 18 countries between May 11, 2012, and Oct 9, 2013. Patients were adults with chronic HCV genotype 1b infection who were treatment-naive; previous non-responders to peginterferon alfa plus ribavirin; or medically ineligible for, previously intolerant of, or ineligible for and intolerant of peginterferon alfa plus ribavirin. Treatment-naive patients were randomly assigned (2:1 ratio) by an interactive voice-response system with a computer-generated random allocation sequence (stratified by cirrhosis status) to receive daclatasvir 60 mg once daily plus asunaprevir 100 mg twice daily or placebo for 12 weeks. Patients and investigator sites were masked to treatment assignment and HCV RNA results to the end of week 12. The treatment-naive group assigned to daclatasvir plus asunaprevir continued open-label treatment to the end of week 24; participants assigned to placebo entered another daclatasvir plus asunaprevir study. Non-responders and ineligible, intolerant, or ineligible and intolerant patients received open-label daclatasvir plus asunaprevir for 24 weeks. The primary endpoint was sustained virological response at post-treatment week 12. Efficacy analyses were restricted to patients given daclatasvir plus asunaprevir. This trial is registered with ClinicalTrials.gov, number NCT01581203. FINDINGS: This study included 307 treatment-naive patients (205 received daclatasvir plus asunaprevir and 102 received placebo; all randomly assigned patients received the intended treatment), 205 non-responders, and 235 ineligible, intolerant, or ineligible and intolerant patients. Daclatasvir plus asunaprevir provided sustained virological response in 182 (90%, 95% CI 85-94) patients in the treatment-naive cohort, 168 (82%, 77-87) in the non-responder cohort, and 192 (82%, 77-87) in the ineligible, intolerant, or ineligible and intolerant cohort. Serious adverse events occurred in 12 (6%) patients in the treatment-naive group; 11 (5%) non-responders, and 16 (7%) ineligible, intolerant, or ineligible and intolerant patients; adverse events leading to discontinuation (most commonly reversible increases in alanine or aspartate aminotransferase) occurred in six (3%), two (1%), and two (1%) patients, respectively, with no deaths recorded. Grade 3 or 4 laboratory abnormalities were uncommon, with low incidences of aminotransferase increases during the first 12 weeks with daclatasvir plus asunaprevir and placebo in treatment-naive patients (