Brown's treatment in Berlin involved the destruction of his immune system and a stem cell transplant from a donor with a rare genetic mutation that resists HIV infection. The procedure is too costly and too difficult to replicate on a large scale.

But in the years since his successful treatment in 2007, Brown's story has become a rallying point for scientists who believe the time is now right to seek a cure for AIDS.

Since the AIDS epidemic started 31 years ago, scientists have made great strides in treating the disease. AIDS-related deaths worldwide fell to 1.7 million last year from some 1.8 million in 2010, according to the latest report from United Nations AIDS program (UNAIDS).

Cocktails of powerful HIV drugs can keep the infection at bay for years, but the virus is wily, weaving itself into the DNA of special immune system cells, where it can lie dormant and out of reach of medications. That makes it necessary for HIV patients to take drugs over a lifetime.

As a result of better access to treatment, more patients with HIV are living near-normal lives, but the numbers of patients needing drugs is rising, increasing the future costs of AIDS treatment.

"Treatment is for life, and we know that it is important today and that it can slow the spread of the virus," said Michel Sidibé, executive director of UNAIDS.

But he said treatment should not be an end in itself.

"If we continue to believe it is the endgame, then we will have a challenge to get to 'zero,'" Sidibé said, referring to the goal of ending the epidemic.

"It's a first step," said Francoise Barre Sinoussi, who won a Nobel prize for her part in identifying human immunodeficiency virus. She is co-chair of the International Working Group Towards an HIV Cure, which released its proposed steps toward a cure on Thursday.

Sinoussi said the next step will be determining the cost-effectiveness of the strategy. That work will begin in conjunction with the International Aids Society's 2012 conference, which runs from July 22-27 in Washington.

GETTING RID OF THE VIRUS

Dr. Steven Deeks of the University of California San Francisco division of HIV/AIDS, who is co-chair of the working group, said health professionals see a growing need to "switch from blocking the virus to getting rid of the virus."

Instead of trying to copy the treatment received by Brown, researchers will seek a similar response in a way that is less costly and easier to replicate.

Among the first tasks, according to Deeks, will be to continue basic research in the lab to understand why the virus persists in the body and where it hides out.

Scientists will also need to understand immune system function in HIV-infected patients and determine whether inflammation is playing a role in protecting the virus.

Other teams will need to determine why some patients develop antibodies to the virus, allowing them to control the infection, and whether this can be applied to the search for a cure.

Deeks said doctors need better tests to measure levels of the virus. Researchers will need to develop drugs that flush out the virus from its hiding places in the body, making it more vulnerable to treatment, as well as powerful medications to bolster the immune system's own ability to fight off infection.

Rowena Johnston, of the Foundation for AIDS Research, which is helping fund development of a cure, said the global strategy will help consolidate research efforts.

"Now that we know what the questions are, we can focus our efforts in the right direction," she said at a briefing announcing the new push.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Disease, a part of the National Institutes of Health, said his agency supports the work but that it is far too early to handicap its success.

"We still have so much discovery to do with regard to a cure that there's no guarantee when or if it will happen. We're sort of where we were over a decade ago with a vaccine," he said.

Back then, scientists were far less certain about vaccine prospects after repeated trial failures, but sentiment changed in 2009 with the first report in Thailand of a modestly successful HIV vaccine trial.

"Now I can say, I'm confident that we'll get a vaccine, I just can't tell you when. With a cure, we're still at the very nascent phase of discovery," Fauci said.

(Additional reporting by Susan Heavey and Salimah Ebrihim in Washington; Editing by Michele Gershberg and Cynthia Osterman)

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