Atea Pharmaceuticals (AVIR) said Wednesday that the first patient has been dosed in its late-stage trial comparing the combination regimen of bemnifosbuvir and ruzasvir with the combination regimen of sofosbuvir and velpatasvir for the treatment of chronic hepatitis C virus.

The bemnifosbuvir and ruzasvir regimen will be administered orally once a day for eight weeks in patients without cirrhosis or 12 weeks in patients with compensated cirrhosis, while the sofosbuvir and velpatasvir regimen will be administered orally once a day for 12 weeks, the company said.

The company said infection with chronic hepatitis C virus is the leading cause of liver cancer in the US, Europe and Japan.

Shares of Atea Pharmaceuticals were down more than 30% in recent premarket activity Wednesday.