Combination antiviral therapy for hepatitis C

The Food and Drug Administration has approved the use of a single pill containing two different antiviral drugs for the treatment for hepatitis C. It is the first combination pill approved for the disease, and also the first treatment that does not contain interferon or ribavirin. The new hepatitis C drug, called Harvoni, is a mixture of the antiviral drugs ledipasvir and sofosbuvir. Ledipasvir (pictured) is an inhibitor of the hepatitis C virus protein NS5A, which has multiple roles in the viral replication cycle that include RNA synthesis and virus particle assembly. The mechanism of NS5A inhibition by ledipasvir is not known. Sofosbuvir is a previously licensed inhibitor that targets the viral RNA-dependent RNA polymerase. It is an analog of the nucleoside uridine, one of the four building blocks of RNA. Sofosbuvir is utilized by the viral RNA polymerase, leading to inhibition of viral RNA synthesis. The use of single antiviral drugs (monotherapy) to treat RNA virus infections is always problematic because resistance usually arises rapidly. Dual-therapy pills like Harvoni are better, but the best are triple-therapy pills. Triple therapy formulations such as Atripla have been used successfully to treat infections with HIV-1, and presumably there will be mixtures of three antiviral drugs for treating hepatitis C. Let’s use HIV-1 to illustrate the value of treating infections with multiple antiviral drugs. The HIV-1 viral genome, like that of HCV, is slightly le...
Source: virology blog - Category: Virology Authors: Tags: Basic virology Information AIDS antiviral drug drug resistance ebola virus Harvoni HCV hepatitis C virus hepatocellular carcinoma HIV-1 ledipasvir liver mutation rate sofosbuvir triple therapy uridine Source Type: blogs