Clinical experience Efficacy of ISENTRESS in treatment-experienced patients BENCHMRK 1 and BENCHMRK 2 (ongoing multi-centre, randomised, double-blind, placebo- controlled trials) evaluate the safety and anti-retroviral activity of ISENTRESS 400 mg b. i. d. vs. placebo in a combination with optimized background therapy (OBT), in HIV-infected patients, 16 years or older, with documented resistance to at least 1 drug in each of 3 classes (NRTIs, NNRTIs, PIs) of anti-retroviral therapies.