Merck: 4-week hepatitis C treatment too short

The race is on for new treatments to fight hepatitis C, a viral disease that affects up to 180 million people worldwide.

Gilead Sciences' Sovaldi, approved last year, set a record in its first year on the market, bringing in more than $3 billion in quarterly sales. The company just received approval of a second pill that combines Sovaldi with another drug to shorten treatment for some patients to as little as eight weeks from 12 weeks.

Merck aimed to trump that, with a trio of drugs it tested in treatment times as short as four weeks. However, results released Sunday at the American Association for the Study of Liver Diseases meeting in Boston showed the four-week plan missed expectations.

"We did an experiment to look at four weeks, six weeks and eight weeks, and as it turns out the four-week duration might be a little too short," Eliav Barr, head of infectious disease clinical research at Merck, said in an interview Monday. "But it helped us a lot because we're now focused around a box of six to eight weeks and that's much of an improvement compared with what's available, which is 12 to 24 weeks."

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