Description: Sofosbuvir and velpatasvir are two different antiviral medications combined into a single tablet. This fixed-dose combination is used to treat chronic hepatitis C (HCV), which is a viral infection that causes liver damage. Sofosbuvir is a nucleotide hepatitis C virus (HCV) NS5B polymerase inhibitor, and velpatasvir is an HCV NS5A replication complex inhibitor.

Indication: This combination is used to treat chronic hepatitis C virus (HCV) infection in adults and children aged 3 years and older. It is effective against all six major HCV genotypes (1, 2, 3, 4, 5, and 6), with or without cirrhosis. In some cases, particularly for patients with decompensated cirrhosis, it may be used in combination with another drug, ribavirin.

Mechanism of Action: The combination works by targeting two different proteins essential for the hepatitis C virus to replicate and spread within the body.

• Sofosbuvir: It is a prodrug that is converted into an active form within liver cells. This active form mimics a building block of RNA and works as a “chain terminator,” effectively stopping the virus’s RNA-dependent RNA polymerase (NS5B) from synthesizing new viral RNA.
• Velpatasvir: It inhibits the non-structural protein 5A (NS5A), which is a crucial protein for HCV RNA replication and the assembly of new virus particles. By inhibiting NS5A, velpatasvir prevents the formation of the viral replication complex.

The use of two different mechanisms of action makes this combination highly effective and helps to prevent the development of drug resistance.