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  • Two-drug combo yields success in Thai HIV study


Researchers in Thailand have found that a combination of two drugs can cut the transmission of HIV from pregnant women to their babies to less than one in 50 (or just 2 per cent).

The treatment is three times more effective than the single-drug regimen currently used in Thailand, which reduces transmission to 6.3 per cent. In the absence of any treatment, more than a third of babies born to HIV-positive mothers develop the disease.

"This is a very important advancement which brings us closer to eradicating paediatric AIDS [in Thailand]," says Vallop Thaineau, permanent secretary of health at the Thai Ministry of Public Health, and a researcher in the study, which also involved French and US scientists.

The findings were publicly released by lead researcher Marc Lallemant of the French Institute of Research for Development (IRD) at an AIDS conference in San Francisco last week. The Thai government — which was given advance notice of the results last year — has already decided to implement the new treatment programme.

The study, known as the Perinatal HIV Transmission Programme, involved more than 1,800 HIV-positive pregnant women in 37 hospitals across Thailand, who were given one of three treatments.

All groups received the standard treatment used in Thailand, namely the antiretroviral drug zidovudine (AZT), which is given to HIV-positive women in the latter stages of pregnancy, during labour and delivery, and to newborns for the first week after birth.

Women in the second group were also given a single dose of nevirapine at the onset of labour. And in the third group, both mothers and infants were given one dose of nevirapine in addition to the standard treatment.

The rate of transmission from mother to baby was 6.3 per cent with the standard treatment, 2.8 per cent in the second group and 2.0 per cent in the third group.

"The data from the Thai study are encouraging," says Ward Cates, president of Family Health International. "They show that a relatively simple two-drug 'preventive' regimen can be … more effective than the use of single-dose nevirapine [in reducing mother-to-child transmission]."

He adds: "The issue will be how to support the production and distribution costs of an extra drug to low-resource areas."

The study raised one additional concern, in that one in five women who received nevirapine were found to develop resistance to the drug. This could reduce their chances of later fighting the illness using triple-drug therapies that include nevirapine.

Sophie Le Coeur, an epidemiologist involved in the study, told SciDev.Net that the research group is now looking into the problem of resistance. "The priority right now is to save the children. There are other solutions for the mothers," she says.

Marie-Louise Newell of the UK Institute of Child Health agrees that concerns about resistance should not affect treatment recommendations. "The benefits of single dose nevirapine in reducing mother-to-child transmission far outweigh the poorly quantified potential adverse affects on the small proportion of women who need treatment soon after delivery," she says.

More than 1,500 newborns are born with HIV every day, and 95 per cent of these live in developing countries where monthly triple therapies commonly taken by pregnant mothers in industrialised nations are not affordable.

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