Merck has announced that the first patient has been enrolled in the company’s global phase III clinical trial, ONCEMRK. ONCEMRK is assessing a once-daily investigational formulation of ISENTRESS (raltegravir), known as reformulated raltegravir, as part of combination HIV therapy for treatment-naïve HIV-1-infected adults. ISENTRESS film-coated tablets currently are administered twice daily in accordance with the approved prescribing Information.

“ISENTRESS has been a significant component of first-line HIV-1 treatment for more than six years as a twice-daily component of antiretroviral therapy,” said Jürgen Rockstroh, M.D., University of Bonn, Bonn-Venusberg, Germany, a clinical investigator on this study.

ISENTRESS is an integrase inhibitor indicated in combination with other antiretroviral (ARV) agents for the treatment of HIV-1 infection in patients four weeks of age and older. The use of other active agents with ISENTRESS is associated with a greater likelihood of treatment response. Severe, potentially life-threatening and fatal skin reactions have been reported with ISENTRESS. Additionally, during the initial phase of combination ARV treatment, immune reconstitution syndrome may occur.

The ONCEMRK trial is a multicenter, double-blind, randomized, active-controlled study evaluating the safety, efficacy, tolerability and pharmacokinetics of reformulated raltegravir 1200mg (dosed as two 600mg tablets) once daily, compared with ISENTRESS 400mg twice daily, both in combination with once-daily tenofovir/emtricitabine over 96 weeks. The primary endpoint of the non-inferiority study is the proportion of patients achieving viral suppression (

“We remain dedicated to investigating new applications for ISENTRESS and to further expanding our knowledge of this HIV-1 treatment,” said Peter Sklar, M.D., M.P.H., director, Clinical Research, Merck Research Laboratories.

More than 160 centers in more than 25 countries are expected to participate in the ONCEMRK trial in the coming months. Merck is planning for the program to include approximately 750 patients worldwide.