Gilead should know whether its new Sovaldi-based combination therapy for hepatitis C is approvable for the US market within six months, after regulators assigned a priority review to its marketing application.

The US Food and Drug Administration will consider whether SOF/VEL - a once-daily, fixed-dose combination of the nucleotide analog polymerase inhibitor sofosbuvir (approved as Sovaldi) and the pan-genotypic NS5A inhibitor velpatasvir - is safe and effective for treating the condition.

A decision is expected by June 28 and, if approved, SOF/VEL would be the first all-oral pan-genotypic single tablet regimen for chronic HCV. The combination has also been assigned breakthrough status by the regulator, which is handed to investigational medicines that could offer major advances over existing options.

The filing is supported by data from four Phase III ASTRAL trials. Of the 1,035 patients treated with SOF/VEL for 12 weeks across three of these studies - 21 percent of which had compensated cirrhosis and 28 percent of which had failed prior treatments - 98 percent achieved the primary efficacy endpoint of a sustained virologic response. 

A marketing application for SOF/VEL is also currently under review in the European Union.