In a move that could lead to a new milestone for treatment in the evolution of the worldwide AIDS epidemic, the FDA advisory committee voted 19-3 to endorse the drug's use for controlling HIV infection among the highest risk group - men who have sex with men.

The panel also approved Truvada's use for the domestic partners of HIV-infected people and others at risk for sexual transmission, but several members said there should be more data on the drug's efficacy to justify its use in the wider population.

Dr. Lauren Wood of the National Cancer Institute said she voted against all preventive applications because clinical studies did not measure the dangers of drug-related renal problems among black people, who are among the hardest impacted by HIV infection and the most susceptible to kidney problems linked to AIDS drugs.

"I don't think that is adequate when you're talking about the population that is most at risk," she said.

The recommendation will be forwarded to FDA regulators, who must decide whether to give Truvada final approval as the first drug for use as a preventive treatment for HIV in the United States.

Shares in Gilead Sciences closed 1.2 percent higher at $51.25 before the panel voted. The drug combines Gilead's HIV drugs Emtriva, also known as emtricitabine, with Viread, or tenofovir. It already has FDA approval to treat people infected with the human immunodeficiency virus that causes AIDS.

Nearly 1.2 million Americans are infected with HIV. But clinical research, which shows Truvada to be effective at preventing the spread of HIV among people who take the pill daily, has raised hopes that the United States could stem the growth of a national HIV epidemic that has stubbornly generated 50,000 new infection cases a year for the past two decades.

Studies showed Truvada to be more than 90 percent effective at preventing HIV infection among test subjects who took the drug as prescribed, but only 44 percent effective among test populations that included intermittent use.

STUPENDOUS HARM

"If taken, it works," Dr. John Mellors, chief of the infections diseases division at the University of Pittsburgh, who spoke as part of Gilead's presentation.

"Existing interventions have not reduced the number of new infections annually and new measures are needed," he said.

But panel members expressed concern about prospective FDA guidelines that call for education and training for prescribing physicians but avoid basic restrictions on the availability of the treatment.

Some said drug recipients should be required to undergo regular HIV screening to them from becoming HIV positive while taking the treatment and unknowingly passing drug-resistant HIV strains to their sexual partners.

"The potential for harm here is stupendous. If we were not to pay attention to that, we would have the potential as an advisory committee to do more harm than good," said panel chairwoman, Dr. Judith Feinberg of the University of Cincinnati College of Medicine.

The committee voted after hearing from nearly three-dozen public witnesses from HIV community activists, who warned that the drug's promise could backfire by discouraging the use of condoms and offering false hope to healthy people unlikely put up with side-effects in order to maintain the daily dosage.

Some witnesses expressed concern that Truvada's $14,000 a year price tag could encourage the healthy to treat it as "a party drug" for weekend use, raising the danger of increasing HIV drug resistance and making the treatment harder to obtain for people who are infected with HIV.

"They'll take the drug when they think they need it," said Dr. Catherine Chien, who like many of the meeting's 38 public witnesses works with the nonprofit AIDS Healthcare Foundation, a global organization that says it helps nearly 170,000 HIV and AIDS sufferers.

"This will lead to higher rates of HIV infection and higher rates of HIV drug resistance," she said.

Half a dozen public witnesses endorsed Truvada for preventive use, some saying it would protect people in high-risk groups whose sexual partners are unwilling to use condoms.

"Today is an exciting day for HIV prevention," Dr. Kenneth Mayer of the nonprofit Fenway Institute said after the committee voted.

"Although (Truvada) is not a panacea, this approach can prevent many new infections and could dramatically impact HIV transmission worldwide," he said.

Some panel members, concerned about the danger of drug resistance, urged the FDA to restrict the availability of Truvada as a preventive measures by requiring prescribing physicians to certify through results that their patients are not infected by HIV when they start taking the drug.

Other panel members replied that the practice would be recommended but that requiring such a restriction could pose a burden and prevent HIV patients who need Truvada to manage their infections from getting the drug.

FDA officials also said restrictions could be easily circumvented because the drug is also sold to HIV infected patients.

(Reporting By David Morgan; Editing by Gary Hill, Carol Bishopric and Richard Chang)

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