April 24, 2001 -- Giving AIDS-infected pregnant women two drugsinstead of one may be a more effective way to protect their babies frombecoming infected with HIV.
It was seven years ago that researchers discovered a way to cutthe rate of babies getting HIV from their infected mothers by 70%. Following alandmark study, the drug AZT, which belongs to a class of AIDS drugs calledantiretrovirals, was proclaimed to be the best means of preventing the spreadof HIV infection from pregnant mothers to their babies.
Since then, researchers have begun looking for ways to reduceeven further the amount of virus in the mothers' blood. One option has been toadd additional drugs to AZT, a strategy commonly referred to as combinationtherapy.
In a new study published in the April 25 issue of theJournal of theAmerican Medical Association, Laurent Mandelbrot,MD, and colleagues from a French AIDS research group, say combination therapycould reduce the transmission of the virus by an additional five times.
Of 437 HIV-infected pregnant women who took a combination ofAZT and another drug called Epivir, only seven babies became infected with thevirus. In contrast, among the 858 HIV-infected pregnant women taking only AZT,58 babies became infected.
Currently, doctors are advised to treat pregnant women withjust AZT.
The results are impressive, according to Nathan Shaffer, MD, ofthe Atlanta-based CDC. However, he says it still remains to be seen if they aresignificant enough to change the recommended guidelines for treatment. Shafferwrote an editorial that accompanies this study.
While the combination of the two drugs was more protective thanthe single drug, women who took the combination had more serious side effects,including anemia and significant drops in their white blood cell counts, whichincreases the risk for infection.
More than one-third of the women on the combination of drugshad viruses that developed resistance to Epivir, which limits the type of drugsthey and/or their children can be given in the future for the treatment of HIV.Both of these factors lead experts to question whether the benefits of thecombination are worth the risks.
"There are concerns raised by this study, and if thecombination is going to be used clinically, clearly the mother and especiallythe child need closely monitoring," Shaffer says.
"I don't think we will see this combination ... being a popular[method of] preventing transmission from mother to baby," adds Patricia Flynn,MD.
Treatment of pregnant women with HIV has changed a bit sincethe study was begun in 1997. In addition to other types of combinationtherapies being investigated, there is also recent evidence that having anelective cesarean section reduces the risk of transmitting the virus to theinfant.
Flynn, of St. Jude Children's Research Hospital, in Memphis,Tenn., says the most important thing for doctors to do now is to closelymonitor the babies being born to HIV-infected mothers to be sure the therapiesare not having long-term effects on their development. In the French study,three babies born without HIV infection later developed problems believed to berelated to the drugs.
"It's important in these studies to be able to report on whathappens to these babies [in the long run]," she says. "As we use these verytoxic drugs in pregnant women and throughout the entire pregnancy, we need tocontinue to study these babies who are born uninfected as well."