MERCK PRESENTS INTERIM DATA ON INTEGRASE INHIBITOR

Results from two ongoing Phase III studies of Merck's Isentress (raltegravir) demonstrated significantly greater antiretroviral activity of Isentress combined with optimized background therapy (OBT) versus placebo plus OBT in treatment-experienced HIV patients. These data were collected from a 16-week primary analysis. Isentress, an investigational oral integrase inhibitor, was previously referred to as MK-0518.

BENCHMRK-1 and BENCHMRK-2 are ongoing, 156-week, multicenter, triple-blind, randomized, placebo-controlled studies that compare Isentress plus OBT with placebo plus OBT in terms of reduction in HIV viral load, change from baseline in CD4 cell counts and evaluation of safety and tolerability. Patients who entered the study had failed antiretroviral (ARV) therapies and are infected with HIV that is resistant to one or more drugs in each of the three oral classes of ARV drugs.

In both of these studies, more than 75 percent of patients receiving Isentress plus OBT achieved viral load reductions to less than 400 copies/mL compared with more than 40 percent of patients receiving placebo plus OBT. Both studies also showed that after 16 weeks of treatment, Isentress plus OBT was generally well tolerated. In addition, there were few discontinuations due to adverse experiences.

Isentress is the first in a new class of investigational antiretroviral agents called integrase inhibitors that inhibit the insertion of the HIV viral DNA into human DNA. Inhibiting integrase from performing this essential function blocks the ability of the virus to replicate and infect new cells, according to Merck.