Gilead Sciences is set to terminate the dosing of GS 9190 in combination with pegylated interferon, ribavirin or other direct-acting antiviral agents in patients with hepatitis C in an ongoing trial.

The decision follows reports of two serious adverse events in patients recruited in separate studies. Bott were receiving a four-drug regimen of GS 9190 and one of two protease inhibitors (GS 9451 in one study and GS 9256 in the second).

GS 9190 is an experimental HCV NS5B polymerase inhibitor.

Gilead has decided to proceed with studies that include the combination of GS 9451 (an investigational protease inhibitor), GS 5885 (an investigational NS5A), pegylated interferon and ribavirin.