On October 16th the FDA announced the approval of raltegravir (Isentress®) for the treatment of Human Immunodeficiency Virus (HIV)-1 infection in combination with other antiretroviral agents. The use of raltegravir is recommended for patients who have HIV-1 strains resistant to multiple antiretroviral medications. Raltegravir belongs to a new pharmacologic class of antiretrovirals called HIV integrase strand transfer inhibitors. Integrase is one of the three enzymes necessary for the HIV-1 virus to replicate, and integrase inhibitors can stop the HIV-1 virus from inserting its genes into uninfected DNA. The other two enzymes necessary for viral replication are reverse transcriptase and protease which already are targeted by a variety of antiretrovirals.
According to the FDA’s press release, raltegravir was approved based on data from two double-blind, placebo-controlled studies in 699 HIV-1 infected adult patients with histories of extensive antiretroviral use. HIV viral loads dropped below a measurable threshold of 50 copies per milliliter in 65% of the patients taking the drug, nearly five times as many as the placebo group. Common adverse events reported with raltegravir use were diarrhea, nausea, and headache and abnormal elevated levels of muscle enzymes. Caution is advised when using raltegravir in patients at increased risk for certain types of muscle problems. Currently, raltegravir has not been shown to affect disease progression and patients may still be at risk for developing opportunitistic infections.
Reference: FDA Approves New HIV Drug. Raltegravir Tablets Used in Combination with Other Antiretroviral Agents. FDA News. www.fda.gov. Accessed 10/18/07
Image of Raltegravir, courtesy of Wikipedia