Tuesday, March 5, 2013

Baby Cured of HIV for the First Time, Researchers Say

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A Mississippi baby born with the AIDS virus appears to have been cured after being treated with an aggressive regimen of drugs just after her birth 2½ years ago, an unusual case that could trigger changes in care for hundreds of thousands of babies born globally each year with HIV.

The findings, reported Sunday by researchers, mark only the second documented case of a patient being cured of infection with the human immune-deficiency virus. The first, an adult man known as the Berlin patient, was cured as a result of a 2007 bone-marrow transplant.

The new case was discovered after the baby girl's mother stopped treatment on her, and doctors realized that the virus was undetectable even without drugs, which HIV patients normally must take for the rest of their lives.

Researchers cautioned that the report on the baby girl involves just one patient, and the findings appear to have little immediate relevance to people who contract HIV as adults or adolescents and are almost always diagnosed and treated long after their initial infection. But if further study confirms that very early treatment can cure HIV-infected newborns, it could spur widespread use of such an aggressive regimen in babies born with HIV, nearly all of them in low- and middle-income countries.

World Health Organization guidelines now call for treating infants born to an HIV-infected mother with a modest daily dose of antiretroviral treatment for four to six weeks—or until testing determines the baby's own HIV status. If the baby tests positive, a more aggressive treatment is begun.

But WHO doesn't address use of a more intense medication approach right after birth, in part because few studies have examined the issue. In addition, it is difficult to determine with certainty that early whether a baby is HIV-positive, and overtreatment would risk wasting scarce medications that offer a better chance of helping other patients.

In this case, researchers believe that a doctor's decision to start an aggressive antiretroviral treatment within 31 hours of the infant's birth led to the cure. They theorize that the drugs prevented the formation of so-called viral reservoirs that harbor the virus. These reservoirs have been the key stumbling block to a cure because even though AIDS drugs stop HIV from replicating, the virus lurks in the reservoirs, ready to come surging back when treatment is stopped.

In this case, "the child got therapy and then went off therapy, and now there's no detectable virus," said Deborah Persaud, a pediatrician and AIDS researcher at Johns Hopkins Children's Center in Baltimore and lead author of a study reporting the cure. "That's really unheard of. If people go off therapy, most of them rebound…within a few weeks."

She described the findings at a news conference Sunday in advance of their presentation Monday at the annual Conference on Retroviruses and Opportunistic Infections in Atlanta.

"This is a very important proof of concept" said Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, an arm of the National Institutes of Health. Further research is required "to see if you can generalize this to children who are born into situations where their risk of infection is very high."

The chance an infected pregnant woman will transmit the virus to her baby during gestation, birth or breast-feeding ranges from 15% to 45%, according to WHO. But treatment with antiretroviral therapy during pregnancy and especially around the time of birth cuts the risk of mother-to-child transmission to below 2%. Still, estimates are that between 300,000 and 400,000 infants are born globally each year with the infection, about 90% of them in resource-poor countries in sub-Saharan Africa.

In the U.S., high compliance with prenatal care and routine HIV testing during pregnancy has all but eliminated HIV-positive newborns. From a peak of 1,650 cases in 1991, the U.S. Centers for Disease Control and Prevention says the number is now down to fewer than 200 a year.

In 2010, the number was 174. One of them, born in a rural Mississippi hospital that fall, is now the first case of a child considered cured of the disease.

The baby was born to a mother who hadn't had prenatal care and didn't know her HIV status. A rapid HIV test after the birth revealed that she was infected, prompting doctors to transfer the baby to University of Mississippi Medical Center more than 100 miles away.

There, Hannah Gay, a pediatrician and infectious-disease expert, ordered an HIV test for the infant. She didn't wait for the result. Figuring this was an especially high-risk case, Dr. Gay started the baby on three standard antiretroviral drugs at higher, treatment-level doses. A few days later, the test came back positive, she said, and she kept the infant on the treatment-level doses.

Over the next few weeks, the baby's viral levels gradually declined, and by day 29, HIV couldn't be detected with standard testing. That remained the case for more than a year.

"I saw her once a month; her viral load was undetectable, and her immune system was healthy—what we expect with a baby taking the medicines regularly," Dr. Gay said.

But at about 18 months, for reasons that aren't clear, the mother stopped bringing the baby in for the checks. Dr. Gay summoned health-department and child-protection workers, who found her last August, and she returned to the clinic. The baby had been off therapy for at least five months, Dr. Gay said.

Before resuming treatment, Dr. Gay ordered a test to make sure the baby's virus hadn't developed resistance to any of the drugs. To her astonishment, technicians couldn't find any virus to test.

At first, Dr. Gay worried that she had been treating an uninfected baby for more than a year. But a quick check of her records verified that five different tests had detected the virus in the days and weeks following her birth.

When she was convinced last August, she called a longtime friend and colleague, Katherine Luzuriaga, a researcher at University of Massachusetts Medical School. Dr. Luzuriaga had been working with Dr. Persaud on a study of a group of teenagers who had been born with the virus and treated since infancy and who now had no evidence of virus that could replicate. The pair had set up a network of labs to study whether they could consider taking the teenagers off the drugs.

With that lab network, established with a grant from the Foundation for AIDS Research, a New York-based philanthropy, samples from the baby have been subjected to a variety of the most advanced tests to detect and monitor the AIDS virus.

While the tests have detected an occasional "signal" of the virus, the various analyses from several labs using different techniques "confirms to us that this is a case of 'functional cure,' meaning that the virus hasn't rebounded and that…we can't detect virus activity in this child," Dr. Persaud said. The work also was supported by the NIH.

source: http://online.wsj.com

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