The US Food and Drug Administration (FDA) has approved a new combination product to treat patients chronically infected with the hepatitis C virus (HCV).
Merck & Co’s Zepatier (elbasvir and grazoprevir) can be taken with or without ribavirin and has been approved to treat adult patients with genotypes 1 and 4 of the disease. The drug was designated as a ‘breakthrough therapy’ by the FDA because evidence suggested that it may offer a substantial improvement over available treatment for a serious condition.
The safety and efficacy of Zepatier was evaluated in clinical trials involving 1,373 patients with chronic HCV genotype 1 or 4 infections, with and without cirrhosis. The participants received the treatment with or without ribavirin once daily for 12 or 16 weeks.
The overall sustained virologic response (SVR) rates ranged from 94% to 97% in genotype 1-infected subjects and from 97% to 100% in genotype 4-infected subjects. The most common side effects of Zepatier without ribavirin were fatigue, headache and nausea. The most common side effects of Zepatier taken with ribavirin were anaemia and headache.
Because of a risk of significantly raised liver enzymes in 1% of patients treated with Zepatier, blood tests should be performed before starting therapy and patients should be monitored during treatment. Zepatier should not be given to patients with moderate or severe liver impairment.
The FDA advises clinicians to screen genotype 1a-infected patients for certain viral genetic variations to determine the optimum dosage regimen and duration, which are listed in the product information.