Monday, March 4, 2013

HIV - Important Developments

The report that a 2½-year- old Mississippi baby appears to be cured of HIV, the virus that causes AIDS, has provoked intense interest, excitement and some skepticism among AIDS researchers and the community at large.
The toddler's case, if confirmed in further research, could have important implications for treatment of more than 300,000 babies born with the virus each year—mostly in the developing world.
The baby is the second person ever documented to be cured of the virus during the 32-year global AIDS epidemic. The first, a man named Timothy Brown and known as the Berlin patient, was cured as an adult as a result of a bone-marrow transplant he received to treat his leukemia.
Here are answers to some questions raised by the report, which was disclosed Sunday and formally presented Monday at the annual Conference on Retroviruses and Opportunistic Infections in Atlanta.
WSJ's Ron Winslow reports on the unprecedented cure of the HIV virus in a two-year-old girl in Mississippi and its potential impact on broader treatments. Photo: Getty Images.
Q. Beyond the report of the cure itself, what stands out about this case?
A. Two important details are these: The baby was started on a more aggressive regimen than normal—and within 31 hours of birth—well before test results that confirmed the HIV infection were available. Generally, doctors start with a lower dose and wait for confirmation of infection before starting such an intense regimen, something that can take four to six weeks. Researchers believe the rapid, aggressive treatment likely led to curing the child of the virus.
Second, the mother decided to take the baby off therapy, something a doctor would almost never do. When the baby was brought back for care after a hiatus of at least five months, standard tests were unable to detect any virus. "I fully expected to see that the child's viral load had gone up quite high," said Hannah Gay, the doctor at University of Mississippi Medical Center who started the baby on the intense regimen.
Q. This is just one case. Will this treatment strategy cure more babies?
A. Much more research is required to validate the finding before it could become part of standard treatment. Deborah Persaud, the researcher at Johns Hopkins Children's Center who is the lead author of the cure report, said further studies are now being planned to test the intense, very early treatment regimen in more infants. In addition, the baby will continue to be monitored for her HIV status.
If the findings hold up, the approach could significantly alter developing-world treatment of babies born with HIV, perhaps playing a major role in the global health community's goal of halting HIV infection of newborns. "This news gives us great hope that a cure for HIV in children is possible and could bring us one step closer to an AIDS-free generation," UNAIDS Executive Director Michel Sidibé said in a statement.
Q. What are the implications for people already diagnosed with HIV or who have progressed to developing AIDS?
A. It isn't clear how the new case applies to people with established infections. Such infections are characterized by "viral reservoirs" where HIV lurks in immune-system cells, hidden from treatment and ready to roar back when treatment stops. The latent reservoirs persist for years and are the major barrier to an overall cure of HIV and AIDS.
In the case of the baby, researchers believe the early treatment likely prevented the establishment of the reservoirs, which typically can form very quickly after exposure to HIV.
Q. So was the baby infected or was the infection prevented by the treatment?
A. Some researchers question whether the baby was truly infected. Cells in the baby "may have been infected—there was virus around," said Steven Deeks, an AIDS researcher at University of California at San Francisco. "But the cells being infected weren't the type that become long-lived reservoirs."
The key issue in prevention is reversing the effect of the latent reservoirs, Dr. Deeks said. "What is probably happening [in the Mississippi case] is that latency is being prevented, not reversed."
Q. Why do researchers think the baby was infected with HIV?
A. The baby tested positive for the virus based on five separate tests, including two taken within 31 hours after birth. After treatment began, levels of the virus gradually declined. At one month, the virus couldn't be detected by commonly used tests, an expected result based on the therapy she was given.
Anthony Fauci, director of the National Institute for Allergy and Infectious Diseases, said, "They did the right things in their study." The findings are a "proof of concept" that very early treatment—before the viral reservoirs are established and before the immune system is damaged—could cure babies of the infection.
In any event, if the strategy is proven effective in additional studies, it likely wouldn't matter whether the infections were being prevented or just rooted out before they became established in the reservoirs, researchers said. Babies would still become free of infection.
Q. How would the strategy fit into current efforts to prevent infections among newborns?
A. The well-established approach is to treat infected pregnant women with antiretroviral therapy during pregnancy and during birth. That reduces the rate of mother-to-child transmission to under 2% from a range of 15% to 45%, according to the World Health Organization.
That's why WHO, UNAIDS and other public-health organizations have made providing pregnant mothers in the developing world with access to antiretroviral drugs the primary strategy in preventing mother-to-child transmission.
"We still need to focus on prevention," said University of Mississippi's Dr. Gay. "Prevention works and prevention is the best form of cure."