Tablets of the drug etravirine were approved by the regulatory Food and Drug Administration for the treatment of HIV infection in adults who have failed treatment with other antiretrovirals. Sold under the trade name Intelence, etravirine is a non-nucleoside reverse transcriptase inhibitor, or NNRTI, that helps to block an enzyme that the human immunodeficiency virus needs to multiply, the FDA said Friday. It was approved for use in combination with other anti-HIV medications. Etravirine can reduce the amount of HIV in the blood and increase white blood cells that help fight off other infections, the FDA said. It also may reduce the risk of death or infections that can occur with a weakened immune system. The government gave etravirine a priority review, a status granted to medications aimed at treating serious or life-threatening conditions. Tibotec Pharmaceuticals Ltd., a unit of Johnson & Johnson, said last July that it had requested etravirine be placed on a fast track for review.