In cases of chronic infection by a genotype 1 hepatitis C virus (HCV), the combination peginterferon alfa + ribavirine taken over 48 weeks has a prolonged virological efficacy for 50% of patients. The addition of a viral protease inhibitor for 12 to 32 weeks increases the virological efficacy, but can cause severe adverse effects.
In patients infected by a genotype 2 or 3 HCV, a 24-week course of peginterferon alfa + ribavirine has a virological efficacy in 70% to 80% of cases.
Sofosbuvir’s initial clinical evaluation includes several comparative trials. But these trials investigate its harm-benefit balance in a minimal way. Sofosbuvir has not been compared directly with a viral protease inhibitor in a randomised clinical trial. The evaluation of sofosbuvir in patients infected with a genotype 1 HCV and suffering from cirrhosis is very poor.
Clinical trials have shown that the addition of sofosbuvir to various drug combinations increases their virological efficacy, but there is no guarantee of success.
In practice, in patients with liver damage requiring antiviral drug therapy, sofosbuvir seems to be at least as effective and less harmful than viral protease inhibitors such as boceprevir. Its use makes it possible to reduce the duration of treatment by several months. But there is a great deal of uncertainty as to its adverse effects and its interactions. In genotype 1 cases, the addition of sofosbuvir to the peginterferon alfa + ribavirine combination is an option. In genotype 2 or 3 cases, sofosbuvir is an alternative to peginterferon alfa. However, given the slow progress of hepatitis C and the many unknowns surrounding sofosbuvir, it is a reasonable option to await further clinical evidence to be available.
©Prescrire 1 January 2015
"Sofosbuvir (Sovaldi°). Active against hepatitis C virus, but evaluation is incomplete" Prescrire Int 2015; 24 (156): 5-10. (Pdf, subscribers only).