*One HIV/HCV co-infected patient had not yet reached TW12; HIV/HCV co-infected (RBV-free) arm: 1 lost to follow-up (HCV RNA undetectable at the last visit on record); 2 breakthroughs with low blood levels of MK-5172 and/or MK-8742; HCV mono-infected (RBV-containing) arm: 3 early discontinuations (day 3 [detectable at the last visit] and days 22 and 35 [undetectable at the last visit]).
There were three treatment failures in the HIV/HCV co-infected study arms; one subject completed the treatment regimen but was lost to follow-up (HCV RNA undetectable at the last visit on record); and two co-infected subjects with low pharmacokinetic levels of MK-5172 and/or MK-8742 experienced virologic breakthrough at the 8 week time point (both cases with low blood levels of MK-5172 and/or MK-8742).
The most common adverse events observed in this cohort were fatigue (7%) and headache (8%). The incidence of these adverse events was not increased in patients with HIV. No co-infected patients discontinued due to either an adverse event or study medication intolerance.
About HIV/HCV Co-Infection
Globally, approximately seven million patients are co-infected with HIV and HCV. HCV is the leading cause of morbidity and mortality among those living with HIV-1, and compared to the general population, the overall prevalence of HCV infection is higher among those infected with HIV-1. Furthermore, HIV/HCV co-infected patients have a three times higher rate of progression to cirrhosis and a six times higher risk of hepatic decompression than HCV patients infected with HCV alone, underscoring the need for new therapeutic options for this patient population.
About the C-WORTHY Clinical Trial
C-WORTHY is a randomized, dose-responsive, parallel-group, multiple-site, open-label trial comparing different patient populations exposed to different durations of treatment of MK-5172 (100 mg QD) in combination with MK-8742 (50 mg QD) with or without RBV in patients with chronic HCV infection. A total of 450 patients with HCV GT1 and HCV RNA levels of =10,000 IU/mL have been enrolled in C-WORTHY and randomized across 16 arms to examine difficult-to-treat subpopulations.
The primary objective of C-WORTHY is to evaluate the safety and efficacy of MK-5172 in combination with MK-8742 with or without RBV as assessed by the proportion of patients achieving sustained virologic response at 12 weeks (SVR12) in treatment-na�ve patients and more complex patient groups including prior peginterferon alfa and ribavirin treatment failures, cirrhotic patients and co-infected patients. The aim of the HIV/HCV co-infected arms is to compare on-treatment HCV RNA responses (defined as proportion of patients with HCV RNA <25 IU/mL) in GT1 HIV/HCV co-infected patients treated with MK-5712/MK-8742 with or without RBV with those in mono-infected patients.
In the HIV/HCV co-infection arms, 59 treatment-na�ve, non-cirrhotic, GT1 HIV/HCV co-infected patients on a stable antiretroviral regimen (raltegravir + tenofovir or abacavir with either 3TC or FTC (News - Alert)) were examined. These subjects were randomized at a 1:1 ratio to receive 12 weeks of MK-5172 (100 mg QD) administered concomitantly with MK-8742 (50 mg QD), with or without twice daily (BID) RBV.
Additional data from Merck's Phase 2 program for MK-5172/MK-8742 will be presented at the 49th Annual Meeting of the European Association of the Study of the Liver, April 9-13 in London. Details on the C-WORTHY Study, as well as additional Phase 2 trials for MK-5172 and MK-8742, can be viewed on www.merck.com/clinical-trials.
In October 2013, Merck announced that the U.S. Food and Drug Administration (FDA) granted Breakthrough Therapy designation to MK-5172/MK-8742 for treatment of chronic HCV infection.
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