Epidemiology and Therapy of Chronic HCV Genotypes 4, 5, and 6
Epidemiology and Therapy of Chronic HCV Genotypes 4, 5, and 6
Background The global burden of hepatitis C (HCV) infection is mostly found in Africa, the Middle East and Asia, where HCV genotypes 4, 5 and 6 are common. The literature on these genotypes is sparse and this synopsis will review characteristics of patients infected with these genotypes.
Aim To review characteristics of patients infected with HCV genotypes 4, 5 and 6.
Methods PubMed search for 'hepatitis C' AND 'genotype 4', 'hepatitis C' AND 'genotype 5', and 'hepatitis C' AND 'genotype 6' was conducted and relevant articles were reviewed.
Results Intravenous drug use is generally responsible for HCV genotype 4 infection in developed countries, but unsafe medical practices cause most cases of HCV genotypes 4, 5 and 6 in endemic countries. The sustained virological response (SVR) rate for patients with HCV genotype 4 who receive pegylated interferon and ribavirin for 48 weeks ranges from 40% to 70% in various small studies. The SVR rate is in the 60–70% range for HCV genotype 5 and 70–80% range for HCV genotype 6 following 48 weeks with pegylated interferon and ribavirin. Preliminary data suggest that a shorter course of 24 weeks of pegylated interferon and ribavirin may be acceptable for HCV genotype 6, with an SVR rate of approximately 70%.
Conclusions The current standard-of-care therapy for HCV genotypes 4, 5 and 6 is pegylated interferon and ribavirin for 48 weeks. A shorter course with 24 weeks of therapy may be considered for patients with genotype 6. Newer and much more effective therapies may be forthcoming in the next few years.
The pivotal treatment trials and large epidemiological studies completed for chronic hepatitis C have generally been conducted in North America and Europe, where hepatitis C virus (HCV) genotypes 1, 2 or 3 are prevalent. More developed countries in the East, such as Japan and Korea, also have a similar HCV genotype distribution. HCV genotypes 4, 5 and 6 are common in areas of Asia, Africa and the Middle East where HCV infection is endemic; however, data on the epidemiology and therapeutic response of these genotypes are much more limited. This synopsis will review the epidemiology of these lesser known genotypes as well as their response to anti-viral treatment, including the available data on newly approved protease inhibitors and other novel anti-HCV agents for HCV genotype 4, newer treatment studies for HCV genotype 5 and recent randomised controlled trials (RCT) comparing outcomes of 24 vs. 48 weeks of pegylated interferon (PEG-IFN) and ribavirin (RBV) combination therapy for HCV genotype 6. Recent advances in the understanding of host IFN sensitivity and interleukin-28B (IL28B) genetic polymorphism, which has varying ethnic distribution, as does the distribution of infection of HCV genotypes 4, 5 and 6 infection, will also be reviewed.
Abstract and Introduction
Abstract
Background The global burden of hepatitis C (HCV) infection is mostly found in Africa, the Middle East and Asia, where HCV genotypes 4, 5 and 6 are common. The literature on these genotypes is sparse and this synopsis will review characteristics of patients infected with these genotypes.
Aim To review characteristics of patients infected with HCV genotypes 4, 5 and 6.
Methods PubMed search for 'hepatitis C' AND 'genotype 4', 'hepatitis C' AND 'genotype 5', and 'hepatitis C' AND 'genotype 6' was conducted and relevant articles were reviewed.
Results Intravenous drug use is generally responsible for HCV genotype 4 infection in developed countries, but unsafe medical practices cause most cases of HCV genotypes 4, 5 and 6 in endemic countries. The sustained virological response (SVR) rate for patients with HCV genotype 4 who receive pegylated interferon and ribavirin for 48 weeks ranges from 40% to 70% in various small studies. The SVR rate is in the 60–70% range for HCV genotype 5 and 70–80% range for HCV genotype 6 following 48 weeks with pegylated interferon and ribavirin. Preliminary data suggest that a shorter course of 24 weeks of pegylated interferon and ribavirin may be acceptable for HCV genotype 6, with an SVR rate of approximately 70%.
Conclusions The current standard-of-care therapy for HCV genotypes 4, 5 and 6 is pegylated interferon and ribavirin for 48 weeks. A shorter course with 24 weeks of therapy may be considered for patients with genotype 6. Newer and much more effective therapies may be forthcoming in the next few years.
Introduction
The pivotal treatment trials and large epidemiological studies completed for chronic hepatitis C have generally been conducted in North America and Europe, where hepatitis C virus (HCV) genotypes 1, 2 or 3 are prevalent. More developed countries in the East, such as Japan and Korea, also have a similar HCV genotype distribution. HCV genotypes 4, 5 and 6 are common in areas of Asia, Africa and the Middle East where HCV infection is endemic; however, data on the epidemiology and therapeutic response of these genotypes are much more limited. This synopsis will review the epidemiology of these lesser known genotypes as well as their response to anti-viral treatment, including the available data on newly approved protease inhibitors and other novel anti-HCV agents for HCV genotype 4, newer treatment studies for HCV genotype 5 and recent randomised controlled trials (RCT) comparing outcomes of 24 vs. 48 weeks of pegylated interferon (PEG-IFN) and ribavirin (RBV) combination therapy for HCV genotype 6. Recent advances in the understanding of host IFN sensitivity and interleukin-28B (IL28B) genetic polymorphism, which has varying ethnic distribution, as does the distribution of infection of HCV genotypes 4, 5 and 6 infection, will also be reviewed.
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