The FDA has approved a new fixed-dose combination oral, once-daily pill to treat hepatitis C (HCV) genotypes 1 and 4. The new agent combines elbasvir in a NS5A inhibitor and grazoprevir in a NS3/4a protease inhibitor. The combination can be used in patients with chronic kidney disease and can be used with or without ribavirin, but does not require interferon. Researchers studied the safety and efficacy of the combination in 1373 participants with chronic HCV genotype 1 or 4 infections with and without cirrhosis. Ribavirin was added depending on the clinical setting, and patients were treated for 12 or 16 weeks. The overall sustained viral response ranged from 94-97% in genotype 1 patients and 97-100% in genotype 4 patients. It is recommended that patients with genotype 1a be screened for NS5A polymorphism prior to treatment to establish treatment duration and need for ribavirin. Liver enzyme tests should be monitored during treatment. Elbasvir/grazoprevir is marketed by Merck as Zepatier. The company sent a ripple through the hepatitis C community when it announced its price at $54,600 for 12 weeks, about half the cost of competitors Harvoni and Viekira Pak.