The US Food and Drug Administration (FDA) has granted priority review to Gilead Sciences‘ new drug application (NDA) for a once-daily fixed-dose combination of the NS5A inhibitor ledipasvir (LDV) 90mg and the nucleotide analog polymerase inhibitor sofosbuvir (SOF) 400mg for the treatment of adult patients with chronic hepatitis C genotype 1 infection.

The company filed the NDA for LDV/SOF in February, and the FDA has set a target action date under the Prescription Drug User Fee Act (PDUFA) of 10 October 2014.

Previously, the FDA granted LDV/SOF a breakthrough therapy designation, which is given to investigational medicines that may provide major advances in treatment compared with existing options.

The NDA is based on data secured from three Phase III trials, ION-1, ION-2 and ION-3, which support the use of LDV/SOF in patients with genotype 1 HCV infection, with treatment duration of eight or 12 weeks depending on prior treatment history and whether they have cirrhosis.

"In the US, more than 75% of people infected with HCV have the genotype 1 strain of the virus."

In the US, more than 75% of people infected with HCV have the genotype 1 strain of the virus.

A marketing application for the combination therapy is also under review in the European Union (EU), and was validated by the European Medicines Agency (EMA) in March.

The EMA has accepted the company’s request for accelerated assessment of LDV/SOF, which if granted, will reduce the EMA’s review time of the combination drug by two months. But it does not guarantee a positive opinion from the Committee for Medicinal Products for Human Use or approval by the European Commission (EC).

SOF as a single agent was approved by the US FDA under the tradename Sovaldi in December 2013 and by the EC in January 2014.

Image: FDA priority review for Gilead’s hepatitis C combination therapy. Photo: courtesy of Freedigitalphotos.net.