The U.S. Food and Drug Administration will rescind Merck’s “breakthrough designation” for an experimental hepatitis C treatment, the pharmaceutical giant said Wednesday. The move is the first time the FDA has rescinded a breakthrough designation, according to the agency’s public data.

A breakthrough designation is a program offered by the FDA to speed access to experimental drugs. It lets drugmakers work closely with regulators to analyze clinical trials and expedite the application process. Such a designation is designed for innovative new treatments that represent a “substantial improvement” over current available therapies, according to the FDA’s description.

For more details, go to: http://fortune.com/2015/02/04/fda-rescinds-breakthrough-status-for-mercks-hepatitis-c-drug/