Merck has announced that its hepatitis C drugs -- grazoprevir and elbasvir -- have again been designated breakthrough therapies by the U.S. FDA.
In February, the drugmaker had reported that the FDA had rescinded the breakthrough designation for Merck's experimental hepatitis C treatment, because competing treatments with higher cure rates had been introducted by AbbVie and Gilead.
Merck's drug combo cured at least 90% of infected patients in a mid-stage clinical trials and Merck is testing them in late-stage studies, hoping to bring the new two-drug, single-pill combination to market. The new breakthrough designation covers only two small subpopulations -- patients infected with chronic HCV genotype 4, as well as hepatitis C patients with genotype 1 that have end-stage renal disease and are on hemodialysis
Read the Nasdaq release