The FDA has approved elbasvir and grazoprevir (Zepatier, Merck) with or without ribavirin for the treatment of chronic hepatitis C virus (HCV) genotypes 1 and 4 infections in adults.
Hepatitis C is a viral disease that causes inflammation of the liver, which can lead to diminished liver function or liver failure. According to the Centers for Disease Control and Prevention, approximately 3 million Americans are infected with HCV, of which genotype 1 is the most common and genotype 4 is one of the least common.
The safety and efficacy of elbasvir/grazoprevir with or without ribavirin was evaluated in clinical trials involving a total of 1,373 participants with chronic HCV genotype 1 or 4 infections with and without cirrhosis. The participants received elbasvir/grazoprevir with or without ribavirin once daily for 12 or 16 weeks. The studies were designed to measure whether a participant’s hepatitis C virus was no longer detected in the blood 12 weeks after finishing treatment (the sustained virologic response [SVR]), suggesting that a participant’s infection had been cured.
The overall SVR rates ranged from 94% to 97% in genotype 1-infected subjects and from 97% to 100% in genotype 4-infected subjects across the trials. To maximize SVR rates for patients, the product label provides recommendations regarding the length of treatment with or without ribavirin that are specifically tailored to the characteristics of patients and their virus. It is recommended that health care professionals screen genotype 1a-infected patients for certain viral genetic variations before starting treatment with elbasvir/grazoprevir to determine the dosage regimen and duration.
The most common adverse events associated with elbasvir/grazoprevir without ribavirin included fatigue, headache and nausea. The most common adverse events associated with elbasvir/grazoprevir with ribavirin were anemia and headache.
The label for the elbasvir/grazoprevir combination carries a warning alerting health care providers that elevations of liver enzymes to greater than five times the upper limit of normal occurred in approximately 1% of clinical trial participants, generally at or after week 8 of treatment. Liver-related blood tests should be performed before starting therapy and at certain times during treatment. Elbasvir/grazoprevir should not be administered to patients with moderate or severe liver impairment.
Source: FDA; January 28, 2016.