Results from two ongoing Phase III studies of ISENTRESS? (raltegravir), an investigational oral integrase inhibitor, demonstrated significantly greater antiretroviral activity of ISENTRESS when used in combination with optimized background therapy (OBT) versus placebo plus OBT in treatment-experienced HIV-infected patients who had failed antiretroviral therapies (ARTs), and who had HIV virus resistant to at least one drug in each of the three available classes of oral ARTs.
These data were collected from the 16-week primary analysis time point called for in the 156 week-long study protocol. ISENTRESS has been previously referred to as MK-0518. The brand name ISENTRESS is currently under review by the U.S. Food and Drug Administration (FDA).
In both of these studies, more than 75 percent of patients receiving ISENTRESS [pronounced i-sen-tris] plus OBT achieved viral load (HIV RNA) reductions to less than 400 copies/mL compared to more than 40 percent of patients receiving placebo plus OBT (BENCHMRK-1, 77 percent of patients (N=232) receiving ISENTRESS plus OBT vs. 41 percent of patients (N=118) receiving placebo plus OBT; and BENCHMRK-2, 77 percent of patients (N=230) receiving ISENTRESS plus OBT vs. 43 percent of patients (N=119) receiving placebo plus OBT, p<0.001 for both studies respectively). 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 (BENCHMRK-1, four patients receiving ISENTRESS plus OBT and four patients receiving placebo plus OBT; for BENCHMRK-2, five patients receiving ISENTRESS plus OBT and one patient receiving placebo plus OBT).ISENTRESS is under development by Merck & Co., Inc., Whitehouse Station, N.J. These results were presented as late breakers this week at the 14th Annual Conference on Retroviruses and Opportunistic Infections (CROI).“The efficacy results and tolerability profile that have been seen thus far with ISENTRESS in combination with OBT in this patient population with multi-drug resistant virus are exciting,” said David Cooper, M.D., D.Sc., professor of medicine and director, National Centre in HIV Epidemiology and Clinical Research, University of New Wales, Sydney, Australia. “HIV integrase inhibitors may be a new promising class of antiretroviral agents.”