A screen displays the logo and trading information for Merck, pharmaceutical company on the floor of the New York Stock Exchange (NYSE) in New York, U.S., August 14, 2017. REUTERS/Brendan McDermid

(Reuters) - U.S. drugmaker Merck & Co 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, 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 has seen total sales of its hepatitis C drugs - Sovaldi, Harvoni and Epclusa - sharply drop to $2.9 billion 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.