sofosbuvir/velpatasvir
Epclusa combines sofosbuvir and velpatasvir into a single daily tablet from Gilead for chronic hepatitis C virus (HCV) infection in adults and children aged 3 years and older. The two drugs block different steps the virus uses to copy itself, and the combination can cure HCV across all major genotypes.
This page is based on EMA assessment information for sofosbuvir and MedlinePlus patient guidance for the sofosbuvir–velpatasvir combination; the mechanism is explained in plain language, and analogies are used only where they stay accurate.
How it works
Explains what the medicine does in the body, not dosing, side effects, or safety.
An analogy
Hepatitis C virus is a factory that copies its own blueprints and builds new virus packages. Sofosbuvir shuts down the photocopier (NS5B polymerase), and velpatasvir jams the assembly line (NS5A) so new virus particles cannot be put together. With both lines stopped, the infection is cleared.
In simple terms
Sofosbuvir and velpatasvir are two antiviral medicines that work together to cure chronic hepatitis C. Sofosbuvir blocks an enzyme called NS5B polymerase, which the hepatitis C virus uses as a photocopier to make new copies of its genetic material. Velpatasvir blocks a protein called NS5A, which the virus needs to assemble new virus particles and release them from infected liver cells. Taken together as a single tablet once daily, usually for 12 weeks, the combination stops the virus from multiplying and allows the liver to heal. It is effective against all major genotypes of hepatitis C virus.
In depth
Sofosbuvir is a nucleotide prodrug that, after hepatic activation to GS-461212 (the active uridine analogue triphosphate), is incorporated by HCV NS5B RNA-dependent RNA polymerase into the growing viral RNA strand, causing obligate chain termination because of the 2'-C-methyl modification. Velpatasvir is a pangenotypic NS5A inhibitor that binds domain I of the NS5A protein, disrupting the membrane-associated replication complex and interfering with virion assembly. The combination achieves sustained virological response (SVR12) rates above 95% across HCV genotypes 1–6 in treatment-naive and treatment-experienced patients, including those with compensated cirrhosis.
See it in motion
A schematic animation of the mechanism — simplified for clarity, not drawn to scale.
Hepatitis C virus is a factory that copies its own blueprints and builds new virus packages.
- Sofosbuvir and velpatasvir are two antiviral medicines that work together to cure chronic hepatitis C.
- Sofosbuvir blocks an enzyme called NS5B polymerase, which the hepatitis C virus uses as a photocopier to make new copies of its genetic material.
- Velpatasvir blocks a protein called NS5A, which the virus needs to assemble new virus particles and release them from infected liver cells.
- Taken together as a single tablet once daily, usually for 12 weeks, the combination stops the virus from multiplying and allows the liver to heal.
Target: HCV NS5B polymerase and NS5A protein
NS5B is the RNA-dependent RNA polymerase that copies the hepatitis C viral genome; NS5A is a zinc-binding phosphoprotein essential for viral RNA replication and assembly. The combination blocks both functions.
Approved uses
Approved uses differ by country and change over time. Always follow your local prescribing information.
Approved uses in European Union
EMA- Sovaldi (sofosbuvir) is indicated in combination with other medicinal products for the treatment of chronic hepatitis C (CHC) in adult and paediatric patients aged 3 years and above
Approved uses in United States
MedlinePlus- The combination of sofosbuvir and velpatasvir is used alone or with ribavirin to treat chronic hepatitis C (an ongoing viral infection that damages the liver) in adults and children 3 years of age and older
- Sofosbuvir is a nucleotide HCV NS5B polymerase inhibitor; velpatasvir is an HCV NS5A replication complex inhibitor; the combination stops the virus that causes hepatitis C from spreading inside the body
Official sources
The statements on this page trace back to these records.
- MedlinePlus: sofosbuvir and velpatasvir
MedlinePlus, U.S. National Library of Medicine
- Emc SmPC: Sofosbuvir/Velpatasvir Gilead 400 mg/100 mg film coated tablets (UK licensed product)
Medicines and Healthcare products Regulatory Agency (EMC)
This page explains how the medicine works — it isn’t the patient leaflet. For anything that applies to you, read the leaflet that came with your medicine or ask your pharmacist.
MedUnfold provides educational content and is not medical advice. Always follow your local prescribing information and healthcare professional.