Update on HIV and Hepatitis C Virus Co-Infection

Introduction

Since the 1996 introduction of highly active antiretroviral therapy (HAART) and its contribution to longer life expectancies in patients with HIV disease, the hepatitis C virus (HCV) has become an increasingly important cause of morbidity and mortality in HIV-infected individuals.1 Chronic liver disease is now the leading non-AIDS cause of death in co-infected individuals with HIV.²

With an estimated prevalence of 1.8% of the population, HCV is the most common, chronic blood-borne infection in the U.S.³ According to the Centers for Disease Control and Prevention (CDC), there are an estimated 2.7 million people living with chronic hepatitis C infection.⁴

There are approximately 1.0-1.2 million people living with HIV/AIDS in the U.S.5 In one study, the prevalence of HCV/HIV co-infection was found to be 16.1%, but the CDC estimated the actual prevalence of HCV infection at 25% of HIV-positive people in the U.S.^{2, 6-7} The HCV co-infection prevalence among HIV-positive people may be as high as 50% to 90% in populations such as injection drug users and hemophiliacs in the U.S.^7-8A

lthough the increasing clinical importance of co-infection has become clearer in the past several years, treatment options remained limited. Until recently, interferon-alfa combined with ribavirin was the sole treatment option available for chronic hepatitis C in patients co-infected with HIV. This treatment had a very low rate of effectiveness, and was associated with extensive side effects. Over the past year, four large clinical trials evaluating the combination of pegylated interferon and ribavirin have had promising results in treating HIV/ HCV co-infected patients. Rates of treatment success, measured by sustained virologic response (SVR) of undetectable HCV-RNA following treatment, were reported at 27-44%, with additional patients showing slowed progression of liver disease. As a result, in February 2005, the FDA approved pegylated interferon-a-2a (Pegasys®) and ribavirin (Copegasus®), both marketed by Roche, for treatment of chronic hepatitis C in HIV/HCV co-infected patients.⁹