A new combination of investigational drugs successfully suppressed hepatitis C genotype I infection in a high percent of patients who had not responded to previous treatment in a study led by a University of Michigan hepatologist.

The study, published Jan. 19 in the New England Journal of Medicine, focused on hepatitis C genotype I, which is predominant in the U.S. and the most difficult to treat. Hepatitis C is a virus that infects the liver and can cause liver cancer and liver cirrhosis. It is transmitted through direct contact with infected blood and blood products.

In this pilot study, patients with hepatitis C genotype I infection, who had not responded to previous treatment with PEG-interferon alfa and ribavirin, were given a combination of two investigational direct-acting antiviral agents (daclatasvir and asunaprevir) alone, or along with PEG-interferon alfa-2a and ribavirin.  All the patients saw their hepatitis C viral load drop rapidly, said Anna S. Lok, M.D., professor of internal medicine, division of gastroenterology at the University of Michigan Medical School and lead author of the study.

All 10 patients given the four-drug treatment sustained virologic response with undetectable virus at the end of treatment and at 12 weeks after stopping treatment. Only four of the 11 patients given the two direct-acting antiviral agents only achieved sustained virologic response.

A sustained virologic response or SVR means there is no detectable hepatitis C virus in a patient's blood after treatment is stopped. Achieving sustained virologic response is important, because research has shown that late relapse is rare.

“Although only four of 11 patients given the two direct-acting antiviral agents only achieved sustained virologic response, this is the first study to show that sustained virologic response can be achieved without the use of interferon or ribavirin,” said Lok. “These data are very encouraging because…many patients with hepatitis C choose not to receive treatment for fear that they cannot tolerate those drugs."

The phase II clinical trial was funded by Bristol-Myers Squibb, and the research team included scientists from the company.