Sofosbuvir is the only NS5B inhibitor approved for use so far. Available data indicates it has pan-genotypic activity, a good safety profile, low risk for drug-drug interactions and a high barrier to resistance. It has been studied in all genotypes in combinations with either ribavirin or other DAAs, demonstrating good efficacy. Access to sofosbuvir will be critical as it is currently a backbone drug to create powerful, pan-genotypic regimens with other DAAs. Sofosbuvir is already registered as a single compound by the US Food and Drug Administration (US FDA), the European Medicines Agency (EMA) and seven other National Medicines Regulatory Agencies (NMRAs) worldwide.