Raltegravir



Raltegravir (MK-0518, brand name IsentressTM) is an experimental antiretroviral drug from Merck & Co. It is the first to enter Phase III clinical trials in the integrase inhibitor class. It targets integrase, an enzyme that HIV uses to integrate its genetic material into human cells. Raltegravir, and other integrase inhibitors, are often termed strand transfer inhibitors. This refers to the process of DNA strand transfer from the viral genome to the host genome.

During 2006, the drug entered Phase III clinical trials, and it is available to certain patients with advanced HIV disease through an expanded access program. 

Raltegravir is taken orally twice daily. Doses of 200, 400, and 600 mg have been studied.

At the 2007 Conference on Retroviruses and Opportunistic Infections, researchers presented Phase III data showing that 77% of patients taking the 400 mg dose of raltegravir plus other antiretroviral drugs reached HIV viral loads below 400 copies, nearly twice as many compared with a control group.

On September 5, 2007, the FDA's Advisory Committee unanimously recommended the accelerated approval of Isentress.