Health Informer - Medical News: Studies Hint at Strategies to Cure AIDS

Friday, July 27, 2012

Studies Hint at Strategies to Cure AIDS - MedPage Today

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ByÂ Ed Susman, Contributing Writer, MedPage Today

Published: July 27, 2012

WASHINGTON â€" Two new human studies offer hints that there may be pathways that can lead to a cure for HIV, the virus that causes AIDS, researchers said here at the International AIDS Conference.

In one study, two patients achieved almost complete eradication of HIV throughout their body after they underwent allogeneic stem-cell transplantation. However, Dan Kuritzkes, MD, of Brigham & Women's Hospital/Harvard Medical School, who discussed his group's study at a press briefing, said he couldn't call the patients cured because they were still on antiretroviral therapy.

In a second study, French researchers from the Agence Nationale pour le Recherche sur le Sida said that six of eight patients remained off-treatment and in control of their virus following a regimen in which they were treated within 10 weeks of infection, then had suppressive therapy for a year, and then interrupted therapy. These patients have remained free of viral rebound for as long as 6 years, said Asier Saez-Ciron, MD, from Institut Pasteur, Paris.

"Cure research has basically shifted from the lab and into the clinic," Steven Deeks, MD, of the University of California at San Francisco, told MedPage Today. "Now it is up to the clinical trialists to begin to take these ideas and move them forward."

"The enthusiasm is not that we are going to have a cure any time soon. The enthusiasm is that it is now possible and there is a group effort aimed in this direction," he said. "No one thinks that this is going to be easy, but that it is possible, and now there is global buy-in. It could take decades unless we get really lucky. This is going to be a trial of errors and is probably going to require combination therapy -- but we have gotten lucky before."

Although most highly active antiretroviral therapies are effective in lowering HIV to undetectable levels for years, numerous studies have found that once treatment stops, the virus rebounds quickly, strongly, and inevitably.

Kuritzkes and colleagues were attempting to replicate the so-called "Berlin patient" who, after stem-cell transplantation from a donor whose stem cells had natural immunity to HIV infection, has been free of HIV without being on medication for 5 years.

He and colleagues gave stem-cell transplants to two long-term HIV patients in a way that allowed them to remain on antiretroviral therapy throughout the process. A very sensitive test showed that tiny amounts of HIV remained in their bodies before and after the transplant, but -- as the transplanted cells developed into a new immune system -- the traces of HIV declined and now cannot be found.

In a sense, Kuritzkes said, the presence of antiretroviral therapy throughout the process amounted to "pre-exposure prophylaxis for a new immune system."

The French experiments were an attempt to create long-term so-called elite-controllers who are infected with HIV but have essentially undetectable virus without antiretroviral therapy.

Seaz-Ciron reported that in the so-called VISCONTI patients in his study, "treatment initiated at primary HIV infection leads, after treatment interruption, to a low â€" but inducible â€" durable HIV reservoir distributed mainly in short-lived memory CD4-positive T cells that mimic the natural distribution observed in elite-controllers."

David Margolis, MD, of the University of Pennsylvania in Philadelphia, another prominent researcher in attempts to find a cure for HIV, said at the press briefing, "We are very careful about what we say. We define cure in several different ways and the different kinds of cure and eradication therapy mean different things to different people."

"Perhaps we should come up with a different term like 'complicated eradication chemoimmunotherapy' to slow people down," he jested.

"But this is where the field is headed," he said, returning to the seriousness of the topic. "You can't argue about the value of the goal, and I can't say how long it will take." He cautioned, however, that even if eradication is achieved, "people can get infected again."

Deeks, citing the long road from zidovudine monotherapy in 1987 to effective combination therapy a decade later, said he would be "shocked" if a cure could be achieved in the same time frame. "My feeling is that the barriers to a cure are far greater than that to achieve combination therapy and it is going to take much longer to get there."

"What we are going to see over the next few years will be a number of pilot-type studies that will identify potential hits and then go from those promising results into further studies, and that is going to take well over a decade."

The press briefing and the new study presentations were preceded by a 2-day symposium that reviewed work in the field.