The US Food and Drug Administration (FDA) has approved the combination drug Zepatier (elbasvir and grazoprevir) for the treatment of adult patients with chronic hepatitis C virus (HCV) with genotypes 1 and 4 infections. Zepatier (pronounced ZEP-at-teer), manufactured by Merck & Co. Inc., is indicated for use with or without ribavirin.
The approval, which was announced on January 28, 2016, was based largely on six clinical trials designed to evaluate the safety and efficacy of the drug when used both with and without ribavirin. A total of 1,373 participants with chronic HCV genotype 1 or 4 infections were enrolled in the trials. Among the subjects were those who had failed previous regimens containing PEG-interferon/ribavirin, those with compensated cirrhosis and HIV, and patients with severe renal impairment who were on hemodialysis.
Patients in the trials received Zepatier, either with or without ribavirin, once daily for 12 or 16 weeks. The studies were designed to measure whether a patient achieved a sustained virologic response (SVR), meaning they no longer had detectable virus in their blood 12 weeks after finishing treatment. The overall SVR rates ranged from 94%-97% in genotype 1-infected patients, and from 97%-100% in genotype 4-infected patients.
According to the FDA release, to maximize SVR rates, the product label provides recommendations regarding length of treatment with or without ribavirin specifically tailored to the characteristics of the patient and the virus. It is recommended that healthcare professionals screen genotype 1a-infected patients for certain viral genetic variations prior to starting treatment with Zepatier to determine dosage regimen and duration. The label will contain a warning that in 1% of clinical trial subjects, liver enzymes were five times higher than the upper limit of normal, occurring about 8 weeks after treatment began. Lab tests should be conducted to monitor these enzymes. Further, Zepatier is contraindicated for patients with moderate to severe liver impairment.
The most common side effects of Zepatier without ribavirin were fatigue, headache and nausea. The most common side effects of Zepatier with ribavirin were anemia and headache.
“Today’s approval provides another oral treatment option for patients with genotypes 1 and 4 HCV infections without requiring use of interferon,” said Edward Cox, MD, director of the Office of Antimicrobial Products in the FDA’s Center for Drug Evaluation and Research.
Read the complete FDA release.
Source: FDA news release dated January 28, 2016
