For HIV-infected children in the developing world, treatment choices have been limited by concerns over the possible development of resistance to drugs they received as infants during failed attempts to prevent their infection in the first place.
But a new U.S. National Institutes of Health-funded study suggests there may be a way to administer one particularly cheap and practical HIV drug -- nevirapine -- safely and effectively to many of these children.
The finding was detailed by study co-author Louise Kuhn, a professor of epidemiology at the Mailman School of Public Health at Columbia University in New York City, and Dr. Lynne Mofenson, chief of the pediatric, adolescent and maternal AIDS branch of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, during a recent teleconference.
The study itself will be published in the Sept. 8 issue of the Journal of the American Medical Association.
Mofenson noted that globally 430,000 infants become infected with HIV. About 90 percent of these children live in sub-Saharan Africa.
To tackle this immense problem, public health officials often turn to nevirapine. A single dose of the drug given at birth to the newborn of an HIV-infected mother can reduce the risk of HIV transmission by as much as 50 percent, Mofenson explained.
However, those infants who go on to become infected run the risk of developing a nevirapine-resistant strain of virus. And resistance testing, though available, is far too expensive to be considered a practical screening tool in the developing world.
So, about three years ago the World Health Organization recommended that HIV-infected children who had first been given nevirapine not be given the effective and cost-effective treatment again in favor of a costly protease inhibitor cocktail that is difficult to store and transport.
In this latest study, the researchers focused on the treatment of 195 children infected with HIV who were cared for at one hospital in Johannesburg, South Africa, between 2005 and 2009.
For these children, nevirapine at birth had failed to prevent HIV infection.
As a result, each child was placed on a protease inhibitor regimen, which involved three drugs: ritonavir-boosted lopinavir, stavudine and lamivudine. All the children fared well on this cocktail, having maintained a desirably low viral load for a minimum of three months over the course of their first year of treatment.
At the launch of the study, about half the children were randomly switched to a nevirapine treatment: namely, replacing ritonavir with nevirapine in the drug cocktail. The other children stayed with their standard protease inhibitor regimen. Blood samples were taken at 4, 12, 24, 36 and 52 weeks.
The authors found that children who had fared well (for an average of nine months) under a non-nevirapine protease-inhibitor drug regimen appeared to fare even better once they switched to a nevirapine treatment.
"Those children who changed to nevirapine were actually more likely to maintain the virus below 50 copies per milliliter (ml) in the blood, which is the lowest detectable limit that we use to measure the amount of virus in the blood," explained Kuhn.
Among the nevirapine group, 66 percent of the children remained below this threshold. For the standard treatment group, just 42 percent achieved that goal.
However, they cautioned that about one in five of the children who switched to nevirapine did not fare well, with viral loads rising beyond 1,000 copies/ml.
Nevertheless, with a majority of children reacting well to the switch, Kuhn and her colleagues suggest the approach could cut costs and improve treatment, so long as viral loads are monitored.
"What this shows is that this is a unique and innovative, but also reasonable, alternative strategy, and it will allow us to treat many more children," Mofenson said. "Because compared with the protease inhibitors we use now, nevirapine is much less expensive -- about $55 a year per child compared to about $280 a year for the PIs."
"So this will allow us to treat five times as many children for the same price," she noted. "Which is why this is so critical."
Kuhn added that nevirapine offers other crucial pluses.
"Our group is very, very encouraged by these results, because the biggest factor in HIV treatment is adherence," she explained. "The drugs don't work if you don't take them. And here the big problem is that it's very, very difficult for parents to get their children to take what we currently offer them two times a day because they are really horrible, foul-tasting drugs."
"So if we can move to something like nevirapine - which has a kind of a sweet taste that children don't really mind so much -- it would be very helpful," she said.
Dr. Geoffrey A. Weinberg, a pediatric infectious disease expert at Golisano Children's Hospital at the University of Rochester Medical Center in New York, agreed that a nevirapine treatment option would be helpful.
"The important message is that many children will do better with anti-HIV therapy based on nevirapine," he said.
SOURCES: Louise Kuhn, Ph.D., professor, epidemiology, Mailman School of Public Health, Columbia University, New York City; Lynne Mofenson, M.D., chief, pediatric, adolescent and maternal AIDS Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Rockville, Md.; Geoffrey A. Weinberg, M.D., pediatric infectious disease expert, Golisano Children's Hospital, University of Rochester Medical Center, Rochester, N.Y.; Sept. 8, 2010, Journal of the American Medical Association
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