Use of pill to prevent HIV may be limited in U.S

The first preventive pill for HIV has been hailed as a landmark in the fight against AIDS in the United States, but experts say only a small percentage of those at risk will benefit from it.

U.S. health regulators last month approved Gilead Sciences Inc's Truvada - already used globally to treat the human immunodeficiency virus - for preventing the infection in healthy people at high risk of contracting the virus that causes AIDS.

A number of factors will limit the drug's use for preventing HIV, including the fact that in the United States many people most at risk of infection, as well as their sexual partners, do not have consistent access to healthcare. Even for those with coverage, insurance reimbursement for a $14,000-a-year drug is expected to be tricky.

In addition, therapy with the drug would require otherwise healthy young people to take a pill each day, plus show up for HIV testing every three months.

"There are a number of rather significant implementation challenges," said Dr. Stephen Morin, director of the Center for AIDS Prevention Studies at the University of California at San Francisco. "Part of it has to do with the requirement to take a pill a day, which could be addressed by a more long-term administration of the drug."

Scientists are exploring a variety of tactics for using AIDS drug formulations to prevent HIV infection, including long-acting injections, gels and vaginal rings.

About 50,000 new HIV infections are reported each year in the United States. The number of patients taking Truvada to prevent HIV will likely be "a lot less" than that, said Howard Jaffe, head of the Gilead Foundation and a member of the company's senior management since 1991.

Gilead declined to give its own sales estimate.

"We are not expecting a meaningful increase or uptick in Truvada use from it," Jaffe said, referring to the FDA prevention approval. "We do expect it to enter into the conversation with regard to certain high-risk populations."

He said use of Truvada to prevent HIV infection will likely be most important outside of the United States, as developing countries where AIDS remains an epidemic look for additional ways to curb transmission of the virus.

Gilead has deals, mainly with generic drugmakers in India, to produce low-cost versions of its drugs for use in sub-Saharan Africa and other developing regions.

Dr. Paul Volberding, director of the Center for AIDS Research at the University of California at San Francisco, says Truvada could become a valuable tool for "a small fraction of people" who understand they have a high risk of exposure - mainly female sex workers whose clients won't use condoms and gay men who decide they are going to engage in riskier sex.

"There is an easy consensus now that somebody that is on treatment and fully suppressed has either zero, or close to it, risk of transmitting the virus," Volberding said.