Gilead Says Hepatitis C Patients Had Relapse in Trial, Shares Plunge

Shares of Gilead Sciences (NASDAQ:GILD) fell 14% Friday morning after the drug maker said a majority of patients enrolled in one of its studies experienced a viral relapse within four weeks of completing the 12-week experimental hepatitis C treatment.

Six of the eight patients that previously had a “null” response but were taking GS-7977 plus the widely used antiviral ribavirin as part of Gilead’s Electron study had a relapse.

Gilead acquired the experimental hepatitis C drug as part of its $11 billion purchase of Pharmasset.

Dr. Norbert Bischofberger, Gilead chief scientific officer, said additional antivirals may be needed to effectively treat the disease.

“We will continue to explore a number of therapeutic approaches to address this significant unmet medical need, including combinations with other oral antivirals,” he said.