Pregnant HIV patients are focus

AIDS specialists yesterday called for more aggressive treatment of pregnant women in the developing world to prevent transmission of HIV to their newborns.

That call to action, made in Boston at an international conference of AIDS researchers, comes amid concerns about a side effect of the medication now given in a single dose to thousands of women and their newborns in Africa to prevent transmission. It is also fueled by research presented yesterday showing that a multidrug cocktail given to pregnant women reduced transmission rates to the lowest levels ever reported in Africa, where HIV threatens to wipe out multiple generations.

Multidrug cocktails have revolutionized the treatment of AIDS in the United States during the past decade, but cost has been a barrier to African patients receiving state-of-the-art drugs. But a confluence of forces -- including increased aid from the United States and other governments, foundation support, and decreases in drug prices -- is beginning to make it easier for patients in Africa to receive better care.

''We should be looking at improving access to better regimens wherever that is available, and I think there are many places where that's available," said Dr. James McIntyre, a pediatric AIDS specialist from Johannesburg.

Pregnant women and their doctors have long feared the transmission of HIV from mother to baby. Specialists said that fear is well-founded: If preventive measures are not taken, up to 40 percent of babies born to HIV-infected women fall ill with the virus.

Since 2000, a single dose of a drug called Nevirapine has been administered to an estimated half-million African mothers in labor and, then, their newborns; and it has reduced infection rates by one-half or more among babies.

But scientists have increasingly recognized that Nevirapine use comes at a cost: In a significant percentage of the mothers, that single dose of the drug is enough to encourage the development of mutated strains of the virus that can evade future doses of the medicine. That process is called resistance, and earlier studies had shown that 30 to 40 percent of pregnant women receiving a single dose of Nevirapine developed resistance. But two medical studies released yesterday at the 12th Annual Retrovirus Conference suggest that resistance may develop in up to two-thirds of women.

''It really highlights that resistance is very prevalent following single-dose Nevirapine," said Jeffrey Johnson, a researcher from the US Centers for Disease Control and Prevention.

Johnson was part of a research team that used sophisticated tests to analyze the blood of 40 women who had taken Nevirapine and found that 65 percent had evidence of resistance. But the implications of that finding for the long-term health of women remains unclear, scientists said. For instance, researchers can't say for sure how long the resistance persists. A study from another US research team showed that it waned substantially within a year.

Another study from the West African nation of Cote d'Ivoire, scientists said, demonstrates the potential of using a combination of drugs to improve the health of both mother and baby.

In 2002 and 2003, doctors gave 329 pregnant women doses of an AIDS medication called Combivir, which is a melding of two early generation medicines, AZT and 3TC. The women started taking that drug eight months into their pregnancies.

Then, at the start of labor, they were given a single dose of Nevirapine. They took Combivir for three days after delivery. Their newborns were given AZT for a week and a single dose of Nevirapine on their second day of life. The estimated cost of the treatment is $20 in Africa.

Researchers found that only 4.7 percent of the newborns had contracted the AIDS virus from their mothers and that only 1.1 percent of the mothers had developed resistance to Nevirapine.

''We are clearly among the lowest transmission rates ever reported in Africa," said Francois Dabis, a French researcher involved in the study.

Scientists believe that Combivir blunts the ability of the AIDS virus to devise a way to elude Nevirapine. Asked whether he believed that doctors should wait for further research before prescribing multidrug cocktails for their pregnant HIV patients, Dabis said there is ample evidence that shows the benefits of combination therapy in AIDS patients.

But until such drug regimens are more widely available, specialists and AIDS treatment organizations said they continue to recommend that women receive Nevirapine, even in the face of concerns about resistance.

''For those who have nothing else, we still need single-dose Nevirapine," said Mark Isaac, vice president for policy at the Elizabeth Glaser Pediatric AIDS Foundation, a major provider of HIV care in Africa.

Stephen Smith can be reached at stsmith@globe.com.