Merck's MK-5172/MK-8742 Treatment Shows Anti-HCV Efficacy

Merck announced that its investigational hepatitis C treatment regimen MK-5172/MK-8742 demonstrated strong anti hepatitis C virus (HCV) activity in the ongoing Phase II C-Worthy study.

MK-5172 is an investigational HCV NS3/4A protease inhibitor while MK-8742 is an investigational HCV NS5A replication complex inhibitor. The all-oral, once-daily treatment regimen was tested in HIV/HCV co-infected patients with HCV genotype 1 infection. In the randomized, dose-responsive, parallel-group, multiple-site, open label trial, different patient populations exposed to different durations of treatment of MK-5172 (100 mg QD) combined with MK-8742 (50 mg QD) with or without RBV in patients with chronic HCV infection were compared. 450 patients were involved in C-Worthy and randomized across 16 arms to investigate difficult-to-treat subpopulations.

The C-WORTHY trial’s primary objective was to assess safety and efficacy of MK-5172 combined with MK-8742 with or without RBV as evaluated by the proportion of patients achieving sustained virologic response at 12 weeks. In co-infected patients, administration of MK-5172/MK-8472 for 12 weeks resulted in strong HCV suppression. A safety profile consistent with patients infected with HCV GT1 alone was also observed.

Dr. Eliav Barr, Vice President of Infectious Diseases at Merck Research Laboratories, said, “We are encouraged by the potential of MK-5172/MK-8742 for the treatment of people living with HIV/HCV co-infection, where there remains a need for additional therapeutic options.”

An estimated seven million patients are co-infected with HIV and HCV around the world. HCV is the leading cause of morbidity and mortality among patients living with HIV-1, in whom the overall prevalence of HCV infection is also higher than the general population. Co-infected HIV/HCV patients have a three times higher risk of rate of progression to cirrhosis and six times higher risk of hepatic decompression than HCV patients alone.

The FDA granted Breakthrough Therapy designation to MK-5172/MK-8472 as treatment for chronic HCV infection in October 2013.