Harvoni, one of two hepatitis C treatments sold by Gilead Sciences, is included in a report on side effects.

Over the past few years, billions of dollars have been spent on new hepatitis C medicines because they could eliminate the virus in 90 percent or more of patients. But a new report finds that hundreds of cases of liver failure were associated with the drugs, and the authors suggest that regulators may have been too quick to embrace the treatments as a panacea.

Specifically, 524 cases of liver failure were found, along with another 1,058 reports of severe liver injury, according to side effects reports that were filed with the US Food and Drug Administration and reviewed by the Institute for Safe Medicine Practices. The nonprofit group also noted 761 instances in which the reported side effect was a failure of the medicines to combat the virus. The report arrives just three months after the FDA issued a warning that the drugs could reactivate hepatitis B.