Epidemiology and treatment outcomes of patients with chronic hepatitis C and genotypes 4 to 9.

Pivotal clinical trials of antiviral therapy for chronic hepatitis C have been conducted predominantly in Europe and the United States, where most patients are infected with genotypes 1, 2, or 3. As a result, published data on the outcomes of therapy in patients infected with genotypes 4, 5, and 6 to 9 are limited. However, a major proportion of patients with chronic hepatitis C worldwide reside in geographic areas where genotypes 4 (Africa and the Middle East), 5 (South Africa), or 6 to 9 (southern China and Southeast Asia) are prevalent or even the most common genotypes. The epidemiology of hepatitis C virus genotypes 4 to 9 is reviewed, and the studies reporting the results of antiviral therapy of these genotypes are summarized. The limited data on antiviral therapy in patients with genotypes 4 to 9 highlight the need for further and controlled treatment trials in these populations.