(Reuters) - U.S. drugmaker Merck & Co (>> Merck and Company) said on Friday it would discontinue developing an experimental drug combination for chronic hepatitis C, as competition rises and patient population shrinks.

The decision was made after reviewing mid-stage trial data of the treatments, said the company, which currently sells hepatitis C drug Zepatier.

Merck is the latest drugmaker to move away from the hepatitis C market.

Earlier this month, Janssen Sciences Ireland UC, a unit of Johnson & Johnson (>> Johnson & Johnson), said it would discontinue further development of its hepatitis C research.

Hepatitis C drugmakers have been struggling with slowing sales growth.

Market leader Gilead Sciences (>> Gilead Sciences) has seen total sales of its hepatitis C drugs - Sovaldi, Harvoni and Epclusa - sharply drop to $2.9 billion (2.17 billion pounds) in the second quarter ended June 30 from $4 billion a year earlier.

Hepatitis C causes inflammation of the liver that can lead to diminished organ function or its failure.

An estimated 2.7 million to 3.9 million people in the United States have chronic hepatitis C infection, according to the Centers for Disease Control and Prevention.

(Reporting by Tamara Mathias in Bengaluru; Editing by Sriraj Kalluvila)

Stocks treated in this article : Johnson & Johnson, Gilead Sciences, Merck and Company