A new combination therapy for hepatitis C virus (HCV) from Gilead Sciences could be approved in the US by the summer after being awarded a priority review by the FDA.
The fixed-dose product that combines a nucleotide analogue polymerase inhibitor Sovaldi (sofosbuvir) with velpatasvir - a new NS5A inhibitor - has been filed as a treatment for HCV genotypes 1-6 on the strength of four phase III trials. The FDA is due to deliver a verdict on the application by 28 June.
Velpatasvir (GS-5816) is in the same class as ledipasvir, which is used alongside sofosbuvir in Gilead's big-selling Harvoni combination therapy, but has a broader spectrum of activity against HCV genotypes and could be effective even in hard-to-treat genotype 3 infections.
Gilead has suggested the new combination could be a 'one-size-fits-all' pill, with a reduced need for genotype and viral load testing and monitoring compared to other oral HCV regimens.
The FDA has recognised that potential, having awarded the new product a breakthrough designation, suggesting it could offer a significant advance over current therapies. The four pivotal trials (ASTRAL 1-4) showed sustained virologic response (SVR) rates ranging from 80% to 100% after 12 weeks' treatment, including in patients with liver cirrhosis.
Sofosbuvir/velpatasvir has also been submitted for approval in Europe, and was accepted for review by the EMA in December with accelerated assessment, shortening the review time by up to four months.
Sovaldi broke all records for a new pharmaceutical launch when it reached the market - racking up $10bn in sales in 2014 (its first full year on the market). It has since fallen back as treatment has switched to Harvoni, with sales of the latter currently running at around $2.5bn a quarter.
Meanwhile, Gilead has also reported positive news in the area of hepatitis B virus (HBV) therapy, revealing that its tenofovir alafenamide fumarate (TAF) candidate had hit its objectives in two phase III trials.
The trials involved treatment-naïve and treatment-experienced adults with HBeAg-negative and HBeAg-positive chronic and showed that TAF was as effective as Gilead's older HBV therapy Viread (tenofovir disoproxil). The new drug has been shown to overcome some of the side effects of its predecessor, such as renal impairment and bone thinning.
Pulmonary fibrosis trial halted
There was disappointing news for Gilead this week however after it decided to call a halt to a phase II trial of simtuzumab in idiopathic pulmonary fibrosis. The LOXL2-targeting antibody seemed to be safe but failed to show efficacy in IPF, according to the study's data monitoring committee.
Phase II studies of simtuzumab are continuing in non-alcoholic steatohepatitis (NASH) and primary sclerosing cholangitis (PSC), said Gilead. The antibody - which was acquired by Gilead when it bought Arresto Biosciences for $225m in 2010 - has previously failed to show efficacy in a pancreatic cancer trial.