Review article: the epidemiology and therapy of chronic hepatitis C 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.