Merck’s MK-5172/MK-8742 for the treatment of chronic hepatitis C virus infection has been granted Breakthrough Therapy designation by the FDA. MK-5172/MK-8742 is an all-oral combination regimen consisting of MK-5172, an investigational HCV NS3/4A protease inhibitor, and MK-8742, an investigational HCV NS5A replication complex inhibitor.
 
According to the FDA, the designation of an investigational drug as a Breakthrough Therapy is intended to expedite the development and review of a candidate for use alone, or in combination, to treat a serious or life-threatening disease or condition when preliminary clinical data indicates that the drug may demonstrate substantial improvement over existing therapies.