Faculty Bibliography

BACKGROUND & AIMS: We evaluated the antiviral response of Asian or Pacific Islander (API) patients with chronic hepatitis B (CHB) who had baseline high viral load (HVL), defined as pre-treatment hepatitis B virus (HBV) DNA >/=9 log10 copies/ml, following up to 288 weeks of tenofovir disoproxil fumarate (TDF) treatment. METHODS: A total of 205 HBeAg-negative and HBeAg-positive self-described API patients received 48 weeks of TDF 300 mg (HVL n = 18) or adefovir dipivoxil 10 mg (HVL n = 15) in a blinded fashion, followed by open-label TDF for an additional 240 weeks. The proportions of HVL vs. non-HVL patients with HBV DNA <400 copies/ml were compared. Mean declines in HBV DNA were evaluated in API vs. non-API patients. RESULTS: Throughout the first 72 weeks of treatment, a smaller proportion of HVL API patients reached HBV DNA <400 copies/ml than non-HVL API patients. However, after this timepoint similar proportions of HVL and non-HVL API patients achieved HBV DNA <400 copies/ml (100% vs. 97%, respectively), which was maintained through week 288, where 92% of HVL patients and 99% of non-HVL API patients on treatment had HBV DNA <400 copies/ml. During the 288 weeks of treatment, API patients had similar mean HBV DNA declines as non-API patients, regardless of whether patients were HVL or non-HVL. No API HVL patient had persistent viremia at week 288. No resistance was detected among HVL or non-HVL patients. CONCLUSIONS: API patients with HVL CHB achieve HBV DNA <400 copies/ml with long-term TDF treatment; however, achieving viral suppression may take longer for HVL patients relative to non-HVL API patients.

UNLABELLED: Retreatment of patients who have not achieved sustained virological response (SVR) after treatment with investigational direct-acting antiviral agents (DAAs) has not been extensively studied. We conducted an open-label trial to assess the efficacy and safety of sofosbuvir (SOF) plus pegylated interferon (Peg-IFN) and ribavirin (RBV) in patients with genotype 1 hepatitis C virus (HCV) who participated in previous studies of one or more Gilead investigational DAAs in combination with RBV with or without Peg-IFN. We enrolled 80 patients at 40 sites. All patients received SOF 400 mg once daily plus Peg-IFN-alpha 180 mug/week and weight-based ribavirin (1,000 or 1,200 mg/day) for 12 weeks. The efficacy endpoint was the proportion of patients with SVR 12 weeks after discontinuation of therapy (SVR12). Of the 80 patients enrolled, 36 (45%) had received two or more courses of earlier treatment for HCV and 74 (93%) had at least one resistance-associated variant (RAV) at baseline. SVR12 was achieved by 63 of the 80 patients (79%) treated. Rates of SVR12 were similar across patient subgroups. Presence of RAVs at baseline did not appear to be associated with treatment failure. Seventy-one of eighty patients (89%) experienced at least one adverse event (AE), but most events were mild to moderate in severity. The most common AEs were fatigue, headache, and nausea. No patients discontinued all treatment because of AEs. CONCLUSION: These findings suggest that SOF plus Peg-IFN and RBV for 12 weeks is effective and safe in patients who have not achieved SVR with earlier regimens of one or more DAAs plus Peg-IFN and RBV.

UNLABELLED: Historically, clinical trials of regimens to treat chronic infection with hepatitis C virus (HCV) have used, as their primary efficacy endpoint, a sustained virological response (SVR)-defined as HCV RNA levels below a designated threshold of quantification-24 weeks after the end of treatment (SVR24). More recently, regulatory authorities have begun to accept SVR at 12 weeks post-treatment (SVR12) as a valid efficacy endpoint because of its high rate of concordance with SVR24. However, the concordance between SVR12 and SVR24 has not been systematically assessed with new regimens of recently approved direct-acting antiviral agents. The aim of this study was to assess the concordance between SVR at various post-treatment time points in phase III clinical trials of sofosbuvir (SOF)-containing regimens. We conducted a retrospective analysis of five trials enrolling 863 patients infected with HCV genotypes 1-6. The concordance between SVR at 4 weeks post-treatment (SVR4) and SVR12, and between SVR12 and SVR24, were determined, as well as positive predictive values (PPVs) and negative predictive values (NPVs). Overall, 779 of 796 patients (98.0%) with an SVR4 also achieved an SVR12, making the PPV of SVR4 for SVR12 98% and the NPV 100%. Of the 779 patients with an SVR12, 777 (99.7%) also achieved an SVR24, making the PPV of SVR12 for SVR24 >99% and the NPV 100%. Of patients who relapsed post-therapy, 77.6% did so within 4 weeks of completing therapy. CONCLUSION: Data from phase III studies demonstrate that with SOF-based regimens, with or without interferon, SVR12 and SVR24 correlate closely. Thus, SVR12 can be used effectively to determine "cure" rates in trials and in clinical practice.

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.

Chronic hepatitis B (CHB) continues to be an important public health problem worldwide, including in the United States. An algorithm for managing CHB was developed by a panel of United States hepatologists in 2004 and subsequently updated in 2006 and 2008. Since 2008, additional data on long-term safety and efficacy of licensed therapies have become available and have better defined therapeutic options for CHB. The evidence indicates that potent antiviral therapy can lead to regression of extensive fibrosis or even cirrhosis, thus potentially altering the natural history of CHB. In addition, appropriate choice of antiviral agent can minimize the risk of resistance. This updated algorithm for managing CHB is based primarily on evidence from the scientific literature. Where data were lacking, the panel relied on clinical experience and consensus expert opinion. The primary aim of antiviral therapy for CHB is durable suppression of serum hepatitis B virus (HBV) DNA to low or undetectable levels. CHB patients who have HBV DNA >2,000 IU/mL, elevated alanine aminotransferase (ALT), and any degree of fibrosis should receive antiviral therapy regardless of their hepatitis B e antigen (HBeAg) status. CHB patients with HBV DNA >2,000 IU/mL and elevated ALT but no evidence of fibrosis may also be considered for antiviral therapy. Approved antiviral therapies for CHB are interferon alfa-2b, peginterferon alfa-2a, lamivudine, adefovir, entecavir, telbivudine, and tenofovir, although the preferred first-line treatment choices are peginterferon alfa-2a, entecavir, and tenofovir. In determining choice of therapy, considerations include efficacy, safety, rate of resistance, method of administration, duration, and cost.