Merck has announced the results from two different investigational studies with Victrelis (boceprevir), the company's oral HCV NS3/4A protease inhibitor, used to treat patients coinfected with chronic hepatitis C virus (HCV) and human immunodeficiency virus (HIV-1).
The ongoing randomised multicentre double-blinded Phase IIb coinfection trial is designed to compare the efficacy of 800mg of Victrelis three times daily in conjugation with 1.5mcg/kg peginterferon alfa-2b (P) weekly plus ribavirin (R) 600 to 1,400mg/daily, to therapy with PR alone in adult patients coinfected with chronic HCV genotype 1 and HIV-1.
The study enrolled a total of 100 adult patients, of which two were randomised to the treatment arm receiving Victrelis in combination with PR, while 34 patients in the control arm received PR alone and the remaining 64 patients received Victrelis plus PR.
Following 12 weeks of study, a higher percentage of patients receiving Victrelis plus PR had undetectable HCV-RNA compared to patients receiving PR alone.
The interim analysis from the 24-week on-treatment data also showed that 60.7% of patients receiving Victrelis plus PR achieved sustained virologic response-12 (SVR-12), compared to 26.5% of patients receiving PR alone.
The primary pharmacokinetic drug interaction study is a single-centre three-arm open-label drug-interaction study conducted in 39 healthy adults, who received 800mg of Victrelis three times daily on days one to six.
Following a four-day washout period, patients received either 300mg of atazanavir/100mg of ritonavir once daily, 400mg of lopinavir/100mg of ritonavir twice daily, or 600mg of darunavir/100mg of ritonvair twice daily on days 10-31.
In the pharmacokinetic study, co-administration of Victrelis reduced mean trough concentrations of ritonavir-boosted atazanavir, lopinavir and darunavir by 49%, 43% and 59%, respectively.
Eliav Barr, vice president of project leadership and management for infectious diseases at Merck Research Laboratories said the company's collaborative studies with the French National Agency for Research on AIDS and Viral Hepatitis2 (ANRS) and the AIDS Clinical Trial Group (ACTG), which is funded by the US National Institute of Allergy and Infectious Diseases, will provide greater insight into the potential role of Victrelis in treating patients co-infected with chronic HCV genotype 1 and HIV-1.