Raltegravir (MK-0518): an integrase inhibitor for the treatment of HIV-1.

In the developed world, access to highly active antiretroviral therapy (HAART) has led to significant reductions in the morbidity and mortality attributed to HIV/AIDS. However, the continual emergence of HIV-1 strains resistant to currently available classes of antiretrovirals highlights the need to develop agents with novel mechanisms of action. Successful completion of the HIV-1 viral life cycle depends in part on the integration of complementary DNA mediated by the enzyme HIV-1 integrase, one of three essential enzymes encoded in the viral genome. The integrase inhibitors have demonstrated the ability to act specifically at the strand transfer step during integration, making HIV-1 integrase a valid and attractive chemotherapeutic target for the treatment of HIV/AIDS. In clinical trials, raltegravir has been shown to be a potent drug with a pharmacokinetic profile that supports a twice-daily dosing schedule. In addition, it has demonstrated a favorable side-effect profile in treatment-naive and -experienced patients and a subset of heavy treatment-experienced patients have been able a achieve virologic suppression with raltegravir as part of combination therapy despite limited treatment options. In October 2007, raltegravir was approved by the U.S. Food and Drug Administration (FDA) for the treatment of HIV-1 as part of combination antiretroviral therapy in treatment-experienced patients-providing an additional option for the management of the HIV-1 infected individual.