Wednesday, 25 July 2012

AIDS cure may have two main pathways

WASHINGTON: Investigators are looking into two main paths toward a cure for AIDS, based on the stunning stories of a small group of people around the world who have been able to overcome the disease.

Despite progress in treating millions of people globally with  antiretroviral drugs, experts say a cure is more crucial than ever because the  rate of HIV infections is outpacing the world’s ability to medicate people.

“For every person who starts antiretroviral therapy, two new individuals  are infected with HIV,” Javier Martinez-Picado of the IrsiCaixa AIDS Research  Institute in Spain told the International AIDS Conference in Washington on  Tuesday.

Some 34 million people around the world are living with HIV, which has  caused around 30 million AIDS-related deaths since the disease first emerged in  the 1980s.

While antiretroviral drugs are helping more people stay alive than ever  before, they are costly and must be taken for life. Experts say only a cure or  a vaccine can make a sufficient dent in the deadly pandemic.

While a cure certainly remains years away, Martinez-Picado said scientists  can now “envision a cure from two different perspectives,” either by  eradicating the virus from a person’s body or coaxing the body to control the  virus on its own.

The most extraordinary case of an apparent cure has been seen in an  American man, Timothy Ray Brown, also known as the “Berlin patient,” who was  HIV-positive and developed leukemia.

Brown needed a series of complex medical interventions, including total  body irradiation and two bone marrow transplants that came from a compatible  donor who had a mutation in the CCR5 gene, which acts as a gateway for allowing  HIV into the cells.

People without CCR5 appear to be resistant to HIV because, in the absence  of that doorway, HIV cannot penetrate the cells.

“Five years after the (first) transplant, the patient remains off  antiretroviral therapy with no viral rebound,” said Martinez-Picado.

“This might be the first ever documented patient apparently cured of an HIV  infection.”

However, while the case has provided scientists with ample pathways for  research on future gene therapies, the process that appears to have cured Brown  carries a high risk of death and toxicity.

“Unfortunately this type of intervention is so complex and risky, it would  not be applicable on a large scale,” Martinez-Picado said.

Brown, 47, announced Tuesday he was launching his own foundation to boost  research toward a cure as the US capital hosts the world’s largest scientific  meeting on HIV/AIDS.

“My plan is basically to find donors to get funds to help research and set  up a system to decide who gets the money,” said a frail-looking Brown, 47,  adding that he planned to dedicate his life to finding a cure for others.

“I am living proof that there could be a cure for AIDS.”

Another group of intense interest is known as the “controllers,” or people  whose bodies appear to be able to stave off HIV infection.

One type, known as the “elite controllers,” test positive for HIV but do  not appear to have the virus in the blood, even without treatment. Researchers  estimate there may be a few hundred of these people in the world.

Post-treatment controllers are people who started therapy early and are  able to stop it without seeing the virus rebound. Some five to 15 percent of  HIV-infected people may fall into this category.

More details on a group of “controllers” in France known as the Visconti  Cohort are expected to be released at the meeting this week, as international  scientists share their latest data in the hunt for a cure.

Martinez-Picado also described a “promising” study by US researchers,  published in the journal Nature, that looks into using new drugs to get rid of  the virus when it holes up, or lies dormant in the immune system.

Led by researchers at the University of North Carolina, the small study on  eight HIV-positive men taking antiretrovirals probed how the lymphoma drug  vorinostat could activate and disrupt the dormant virus.

Patients who took the drug showed an average 4.5-fold increase in the  levels of HIV RNA in their CD4+ T cells, evidence that the virus was being  unmasked and demonstrating a new potential strategy for attacking latent HIV  infection.

Last week, international researchers announced a new roadmap toward a cure,  calling for more funds and a renewed focus on curing AIDS, led by Nobel  laureate Francoise Barre-Sinoussi, the co-discoverer of HIV.

“We now actively talk of potential scientific solutions in a way perhaps we  weren’t some years ago,” said Diane Havlir, AIDS 2012 US co-chair and professor  of medicine at the University of California, San Francisco. -- AFP


Post a Comment