Isentress Proves Effective in HIV Treatment-Resistant Patients

July 29, 2008

Two ongoing pivotal Phase III studies of Merck’s experimental HIV/AIDS drug Isentress have shown that it helped suppress the virus for at least 48 weeks in patients who had failed to respond to other treatment.

The studies enrolled patients infected with HIV-1 in which the virus had triple-class drug resistance, which meant patients already had failed to respond to anti-retroviral therapy. At week 16, 355 of 458 patients who took the drug had HIV-1 RNA levels below 400 copies per milliliter, 78 percent, compared with 99 of 236 placebo recipients, or 42 percent, Merck said.

At week 48, 62 percent of the Isentress patients and 33 percent of the placebo patients had achieved the lower HIV-1 RNA level.