Etravirine, sold under the trade name Intelence, is a non-nucleoside reverse transcriptase inhibitor, or NNRTI, that helps block an enzyme, which HIV needs to multiply.

"This is another significant new product for many HIV-infected patients who are NNRTI-resistant and whose infections are not responding to currently available medications," said Dr. Debra Birnkrant, director of the FDA's Division of Antiviral Products.

When used with other active anti-HIV medicines, etravirine reduces the amount of HIV in the blood and increases white blood cells that help fight other infections. In addition, the FDA said etravirine might reduce the risk of death or infections that can occur with a weakened immune system.

Etravirine is distributed by Tibotec Therapeutics, a division of Ortho Biotech Products L.P. of Bridgewater, N.J.