WASHINGTON — U.S. health advisers are poised to decide Thursday on whether to recommend the drug, Truvada, as the first preventive pill against AIDS instead of just a treatment for infected people.

Landmark study results published in 2010 showed that the drug, made by California-based Gilead Sciences, helped ward off HIV in gay men who engage in risky sex behaviors by 44 to nearly 73 percent.

But critics note that the pill is costly — up to $14,000 per year — and some warn that the clinical trial did not represent real-world circumstances and could lead to a spike in unprotected sex and a new surge in AIDS cases.

The Antiviral Drugs Advisory Committee is expected to issue a decision later Thursday. The Food and Drug Administration does not have to follow its advice, though it often does.

Truvada is currently available as a treatment for people with HIV in combination with other anti-retroviral drugs and was FDA approved in 2004.

Drug maker Gilead Sciences Inc. of California has filed a supplemental new drug application to market it for prevention purposes.

The data being mulled comes mainly from the iPrEx HIV Prevention Study, the research was carried out from July 2007 to December 2009 in six countries — Brazil, Ecuador, Peru, South Africa, Thailand and the United States.

The study was conducted among 2,499 men, including 29 transgendered women, between the ages of 18 and 67 who were sexually active with other men but were not infected with the virus that causes AIDS.

Participants were selected at random to take a daily dose of Truvada — a combination of 200 milligrams of emtricitabine and 300 milligrams of tenofovir disoproxil fumarate — or a placebo.

Those in the study who took the drug regularly had almost 73 percent fewer infections. Across the entire study, including those who had not been as faithful in taking Truvada, there were 44 percent fewer infections than those who took a placebo.

The method of taking a drug ahead of potential exposure to HIV is called pre-exposure prophylaxis (PrEP).

After the study's publication in the New England Journal of Medicine, some experts hailed the results as game-changing and the first demonstration that an already-approved oral drug could decrease the likelihood of HIV infections.

However, others have warned of the risks of depending on people — particularly those who may be already engaged in careless behaviors — to take a daily pill.

"There could be an increased risk to men as they may falsely believe they are 100 percent protected and stop using condoms. A reduction in condom use will mean increased risk of transmission and the spread of a drug-resistant virus," said a statement from the AIDS Healthcare Foundation.

"The 44 percent who received a benefit from Truvada in the iPrex Study were intensively counseled monthly and tested frequently for sexual infections — this is not likely to occur in the real world."

Gay men account for more than half of the 56,000 new cases yearly of human immunodeficiency virus in the United States, according to the Centers for Disease Control and Prevention.

A cost-benefit analysis by experts at Stanford University last month suggested the pill would make financial sense among gay men with five or more sex partners per year, but could be prohibitively expensive if promoted for all gay men.

Copyright 2012 AFP Global Edition