Also Known As: Sovaldi, Sofosbuvir
Sofosbuvir (brand name Sovaldi) is a drug used for hepatitis C infection, with a high cure rate. It inhibits the RNA polymerase that the hepatitis C virus (HCV) uses to replicate its RNA. It was discovered at Pharmasset and developed by Gilead Sciences.
Sofosbuvir is a component of the first all-oral, interferon-free regimen approved for treating chronic hepatitis C. Interferon-free therapy for treatment of hepatitis C reduces the side effects associated with use of interferon.
In 2013, the Food and Drug Administration (FDA) approved sofosbuvir in combination with ribavirin (RBV) for oral dual therapy of HCV genotypes 2 and 3, and for triple therapy with injected pegylated interferon (pegIFN) and RBV for treatment-naive patients with HCV genotypes 1 and 4. Sofosbuvir treatment regimens last 12 weeks for genotypes 1, 2 and 4, and 24 weeks for treatment of genotype 3. This is typically half the time as with prior treatments. The label further states that sofosbuvir in combination with ribavirin may be considered for patients infected with genotype 1 who are interferon-ineligible.
The price of sofosbuvir, quoted in various media sources as $84,000 to $168,000 for a course of treatment in the U.S. and £35,000 for 12 weeks in the UK, has engendered considerable controversy, particularly with respect to accessibility in developing countries. 
Sofosbuvir is used for the treatment of chronic hepatitis C, genotypes 1, 2, 3 and 4, in combination with pegylated interferon and ribavirin, or with ribavirin alone. It is also used in HCV patients with an HIV coinfection. The treatment is based on a number of clinical trials, for example the ELECTRON trial which showed that a dual interferon-free regimen of sofosbuvir plus ribavirin produced a 24-week post-treatment sustained virological response (SVR24) rate of 100% for previously untreated patients with HCV genotypes 2 or 3.
In early 2014, the American Association for the Study of Liver Diseases (AASLD) and the Infectious Diseases Society of America (IDSA) jointly published a recommendation for the management of hepatitis C. In this recommendation, sofosbuvir and ribavirin, with or without pegylated interferon, are part of all first-line treatments for HCV genotypes 1 to 6, and are also part of some second-line treatments.