Nanomedicines in the treatment of hepatitis C virus infection in Asian patients: optimizing use of peginterferon alfa.

Asia is endemic for hepatitis C virus (HCV) infection, which is the leading cause of cirrhosis, hepatic decompensation, hepatocellular carcinoma, and liver transplantation worldwide. HCV has six major genotypes and each HCV genotype has its specific geographic distribution. HCV genotypes 1, 2, 3, and 6 are common in Asia. The aim of HCV treatment is to eradicate the virus by effective therapeutic agents; viral clearance is durable after long-term post-treatment follow-up. In most Asian countries, peginterferon alfa (PEG-IFN α) in combination with ribavirin remains the standard of care, and the overall sustained viral response (SVR) rate in Asian HCV patients is higher than that in Western patients. The differences are most significant in patients with HCV genotype 1 (HCV-1) infection, which is attributed to the higher frequency of IFN-responsive or favorable interleukin-28B (IL-28B) genotype in Asian populations than in other ethnic populations. In addition, the introduction of response-guided therapy, where the optimized treatment duration is based on the early viral kinetics during the first 12 weeks of treatment, increases the SVR rate. Recently, telaprevir or boceprevir-based triple therapy was found to further improve the SVR rate in treated and untreated HCV-1 patients and has become the new standard of care in Western and some Asian countries. Many novel direct-acting antiviral agents, either in combination with PEG-IFN α plus ribavirin or used as IFN-free regimens are under active investigation. At the time of this writing, simeprevir and sofosbuvir have been approved in the US. Because the SVR rates in Asian HCV patients receiving PEG-IFN α plus ribavirin therapy are high, health care providers should judiciously determine the clinical usefulness of these novel agents on the basis of treatment duration, anticipated viral responses, patient tolerance, financial burdens, and drug accessibility.