A triple combination of Merck’s grazoprevir, MK-3682, and either elbasvir or MK-8408, given for eight weeks, cured high rates of people with genotypes 1, 2 and 3 of hepatitis C virus (HCV) in a recent trial. Researchers in part A of the Phase II, randomized, open-label C-CREST-1 and -2 trials gave one of four triple-drug regimens, including the NS3/4A protease inhibitor grazoprevir, the NS5B polymerase inhibitor MK-3682, the NS5A inhibitor elbasvir, or the NS5A inhibitor MK-8408, to 93 people with genotype 1, 61 people with genotype 2 and 86 people with genotype 3. All participants were treatment-naive and non-cirrhotic.

Results were presented in a late-breaking abstract at the Annual Meeting of the American Association for the Study of Liver Diseases (AASLD) in San Francisco.

The four regimens included grazoprevir with either 300 or 450 milligrams of MK-3682, plus either elbasvir or MK-8408.

Across all the treatment arms, 98 percent (45 of 46) of those with genotype 1a achieved a sustained virologic response 12 weeks after completing therapy (SVR12, considered a cure), as did 98 percent (46 of 47) of those with genotype 1b. Among the participants with genotype 2, those who took grazoprevir, 450 mg of MK-3682 and MK-8408 had a 94 percent (15 of 16) cure rate, while those who took the other three regimens had cure rates ranging between 60 and 71 percent. Ninety-one percent (78 of 86) of those with genotype 3 were cured across all arms, with comparable rates of 86 to 95 percent between the arms.

All of the regimens were generally well tolerated. The most frequent adverse side effects, occurring in more than 5 percent of all participants, included headache, fatigue, nausea, diarrhea, flatulence and insomnia. There were no drug-related serious side effects.