Abstract and Introduction
Abstract
Purpose of review: The evolution of treatment for patients with chronic hepatitis C virus (HCV) is evolving at a rapid pace. Two new oral antiviral agents, simeprevir and sofosbuvir, have already been approved and are now available for treatment of patients with chronic HCV. Other antiviral agents will be available during 2014.
Recent findings: The protease inhibitor simeprevir was recently approved for use with peginterferon (PEGINF) and ribavirin (RBV) in patients with chronic genotype 1. About 80% of patients achieve a rapid virologic response and can be treated for 24 weeks. The sustained virologic response (SVR) in treatment-naive patients is about 80%. Sofosbuvir, the first polymerase inhibitor, is effective in all HCV genotypes. When utilized with peginterferon and RBV for 12 weeks in treatment-naive patients with genotypes 1, 4, 5 and 6, an SVR of 90% is observed. Sofosbuvir and RBV have also been studied without interferon and represent the first interferon-free therapy for chronic HCV.
Summary: It is now possible to cure chronic HCV in the vast majority of patients with chronic HCV and in many patients without interferon.
Introduction
The treatment of chronic hepatitis C virus (HCV) continues to evolve at an accelerating pace. In 2011, the first two protease inhibitors, telaprevir and boceprevir, were approved to be utilized with peginterferon (PEGINF) and ribavirin (RBV) to treat chronic HCV genotype 1. The addition of a protease inhibitor to PEGINF and RBV represented a huge advance in HCV treatment and increased sustained virologic response (SVR) in the treatment-naive population with HCV genotype 1 from about 40% to 70–75%. The main limitation of these first-generation protease inhibitors was side-effects, particularly anemia, which were more severe than observed with PEGINF and RBV. These adverse events are even more severe and increase the risk of hepatic decompensation in patients with cirrhosis. In a study that included only patients with advanced fibrosis or cirrhosis, many of whom had previously failed PEGINF and RBV, nearly half of all patients treated with either telaprevir or boceprevir developed serious adverse events, 25% discontinued treatment, over half developed severe anemia and required a hematopoetic growth factor and 1–2% died as a result of hepatic decompensation. The patients at greatest risk to develop hepatic decompensation included those with thrombocytopenia and a low serum albumin. The SVR in this cohort was only 40%. In the subset of patients with cirrhosis who failed previous therapy, the SVR was under 20%. Results like these caused many physicians who were treating HCV to pause and wait for a better alternative.
In late 2013, another protease inhibitor simeprevir and the first polymerase inhibitor, sofosbuvir, were approved for HCV treatment. These two antiviral agents offer significant advantages compared with telaprevir and boceprevir when treating patients with HCV genotype 1; the duration of therapy is shorter, the adverse effect profile is superior and the SVR is higher. In addition, sofosbuvir is effective against all genotypes and when utilized with RBV represents the first interferon-free treatment for chronic HCV.
During the past few years, several oral antiviral agents, which inhibit various HCV proteins, have been developed at a rapid pace. These include protease inhibitors, nucleotide and nonnucleotide polymerase inhibitors, NS5A inhibitors and cyclophilin inhibitors. Two or more oral antiviral agents from different classes have been combined and their evaluation in phase 3 clinical trials is well underway. During 2015 multiple oral antiviral combinations are expected to be available to treat chronic HCV (Table 1). The rapid evolution of these treatments will make any recommendations for how to treat HCV in 2014 tentative at best. The treatments that will be available during 2014 are illustrated in Fig. 1. The rapid evolution of HCV treatment has also occurred at a pace that far exceeds the appearance of peer-reviewed publications. The vast majority of cited references are therefore abstracts, which have been presented at national and international meetings during 2013.
(Enlarge Image)
Figure 1.
Treatment regimens for patients with chronic hepatitis C virus (HCV) utilizing the two newest antiviral agents simeprevir (SPV) and sofosbuvir (SOF). Treatment of patients with HCV genotype 1 includes SPV, peginterferon (PEGINF) and ribavirin (RBV) for 24–48 weeks, SOF, PEGINF and RBV for 12 weeks, SOF plus RBV for 24 weeks or SOF and SPV for 12 weeks. The treatment of patients with HCV genotype 2 is SOF plus RBV for 12 weeks. The treatment of patients with HCV genotype 3 is SOF plus RBV for 24 weeks.