Merck & Co's Zepatier received the U.S. Food and Administration's approval on Thursday as treatment for chronic infections in adults involving hepatitis C virus genotypes 1 and 4. The approval is valid whether or not the hepatitis C pill is administered with ribavirin.

As a viral disease, hepatitis C causes liver inflammation that reduces the organ's function or leads it to fail altogether. A lot of people infected with the hepatitis C virus don't show symptoms until after several years when the disease has advanced and the liver damage has grown extensively. Some patients develop cirrhosis, which leads to complications like jaundice, bleeding, infections, fluid accumulation in the abdomen or cancer.

A clinical trial involving 1,373 participants was carried out to test for the efficacy and safety of Zepatier whether or not administered with ribavirin. Participants either had genotype 1 or 4 infections, some with cirrhosis and split into groups to receive treatment for either 12 or 16 weeks.

The clinical trial was developed to assess whether the hepatitis C virus could still be detected in the blood of a participant 12 weeks after undergoing treatment. If the virus is nowhere to be found, then a hepatitis C infection has been cured.

According to the findings of the clinical trial, 94 to 97 percent of those with genotype 1 infections and 97 to 100 percent of those with genotype 4 infections achieved intended results.

Zepatier treatment length should be determined by patient's characteristics and the virus they are infected with to ensure intended results are met. Health care professionals are also advised to screen patients with genotype 1a infections for specific viral genetic variations before treatment starts to determine the dosage duration.

As Zepatier can elevate liver enzymes five times the normal range's upper limit, it is also suggested that liver-related blood tests be done at certain points during treatment. If a patient already has moderate to severe impairment of the liver, they cannot be given Zepatier.

According to Merck, it will be selling Zepatier at a lower list price compared to its competitors.

Approximately, there are 3 million people in the U.S. infected by the hepatitis C virus. Out of this number, genotype 1 infections are the most common while those of the genotype 4 are the rarest, according to the Centers for Disease Control and Prevention.