"Today’s approval marks an important milestone in our fight against HIV," said FDA Commissioner Margaret A. Hamburg. "Every year, about 50,000 U.S. adults and adolescents are diagnosed with HIV infection, despite the availability of prevention methods and strategies to educate, test, and care for people living with the disease.
She added: "New treatments as well as prevention methods are needed to fight the HIV epidemic in this country."
The FDA warned that Truvada should not be used by HIV-positive individuals who desire to prevent transmission of the virus.
The agency recommended that individuals seeking to limit their risk of infection use the drug in combination with other prevention methods such as safe sex, risk-reduction counseling and regular HIV screenings.
Gilead Sciences is required to follow-up Truvada's approval by collecting data on outcomes for women who become pregnant while taking the drug, and other tasks.
An estimated 1,178,350 Americans were living with HIV at the end of 2008, according to the Centers for Disease Control and Prevention.
House Minority Leader Nancy Pelosi (D-Calif.) praised the FDA's "historic" decision in a statement.
"The fight against HIV/AIDS has been one of my top legislative priorities for 25 years," she said. "We must employ each and every strategy that reduces the chances of acquiring HIV as part of a comprehensive approach to save lives in the United States and around the world."
—This post was updated at 5:11 p.m.