Raltegravir

Raltegravir, the first in a new class of orally administered HIV type-1 (HIV-1) integrase inhibitors, selectively inhibits the strand transfer activity of HIV-1 and its integration into human DNA, a key stage in retroviral propagation, thereby limiting viral replication and the infection of new cells. In two randomized, double-blind (with in-house blinding), placebo-controlled, multicentre, ongoing phase III trials, the proportion of patients achieving HIV-1 RNA loads of < 400 copies/mL (primary endpoint) was significantly greater in raltegravir plus optimized background therapy (OBT) recipients than in placebo plus OBT recipients (preliminary 24-week results). The proportion of patients achieving viral loads of < 50 copies/mL was significantly greater with raltegravir plus OBT than with placebo plus OBT in the two studies. In addition, mean CD4+ cell counts (secondary endpoint) were significantly increased from baseline in patients receiving raltegravir plus OBT relative to those receiving placebo plus OBT. Raltegravir therapy was well tolerated overall. The incidence of mild to moderate adverse events was similar in the raltegravir and placebo arms of the two randomized trials.