11 August 2010
In rural Vulindlela, a town 90 kilometres outside Durban, one in 10 girls is HIV-positive by the age of 16; by 24, more than half are infected. For two KwaZulu-Natal scientists, Dr Quarraisha Abdool-Karim and Professor Salim Abdool-Karim, finding effective treatment for a disease that affects mostly women was an urgent priority.
Their journey towards finding effective and safe treatment for women began 20 years ago. Today, the husband-and-wife duo have made a ground-breaking discovery that could alter the course of HIV/Aids treatment for many years to come.
Caprisa 004 gel trial
The scientists recently announced the results of a ground-breaking safety and effectiveness study of an antiretroviral microbicide gel. The tenofovir gel trial, known as the Caprisa 004, involved 889 women at high risk in the Aids-ravaged Vulindlela district near Howick.
The microbicide, containing one percent tenofovir – an antiretroviral drug widely used in the treatment of HIV – was found to be 39% effective in reducing a woman’s risk of becoming infected with HIV during sex, and 51% effective in preventing genital herpes infections.
The study revealed that when the gel was used as clinically specified within 12 hours before and 12 hours after sex, the success rate improved.
Should other studies of tenofovir gel confirm these results, widespread use of the gel, at this level of protection, could prevent over half-a-million new HIV infections in South Africa alone over the next decade. Tenofovir works by preventing the HIV from growing inside human cells.
Overall, 98 women out of the 889 became HIV-positive during the 30 month long trial – with 38 in the tenofovir gel group and 60 in the placebo gel group. Out of the 434 women who tested negative for herpes at the start of the trial, 29 became infected in the tenofovir group and 58 became infected in the placebo group.
The placebo was a gel with no active ingredient.
Speaking to BuaNews, Quarraisha Abdool-Karim said that the use of antiretroviral (ARV) drugs for prevention was novel, adding that tenofovir gel could fill an important HIV-prevention gap by empowering women who are unable to successfully negotiate mutual faithfulness or condom use with their male partners.
Preparations for the study began in 2004 due to not only the very high prevalence of HIV infection in the Vulindlela district, but the rate of new infections in women continuing to rise. In Sub-Saharan Africa, women account for 59% of all infected adults. Young women are especially vulnerable.
“In 2004, we looked at the added value that we could contribute to the microbicides trial that were taking place at that time,” Quarraisha said. “We recognised the urgent need for methods for women. We went back to the drawing board and found that there was a gap in terms of the candidate microbicides that were available and being tested.
“We know that ARVs work for treatment of HIV and are effective in infants not getting infected, and we saw a gap in terms of trials of gel formulation,” Quarraisha said. “The pharmaceutical industry is not investing in preventive methods including methods for women, so we hope that the type of result we’ve shown may increase industry interest for developing further preventive methods for women.”
Confirmatory studies needed
Abdool-Karim said South African scientists were keen in doing the confirmatory studies in terms of the dosing regiments and also looking at bridging populations.
Sixteen- and 17-year-old girls were not involved in the study because of safety reasons, but according to Abdool-Karim there was adequate safety data available, and there was no reason why young women should not be involved, as they were more at risk for the disease.
“We need to sit down with the Medicines Control Council with all the data we have to date and figure out what more is needed and plan and implement those studies needed to get a safe and efficacious microbicide to women,” she said.
“We can’t afford to wait 10 years to do this, or assume that it will happen. If we set a milestone date, it will happen.”
Promising results, further trials needed
Speaking at the 18th International Aids Conference held in Vienna recently, Health Minister Aaron Motsoaledi said he was encouraged by the promising results, adding that this might be the beginning of the answer to the questions that the country had been asking for ages.
The department further noted that the research opened new avenues in the fight against HIV/Aids in South Africa. However, the Treatment Action Campaign had some reservations about the findings of the study.
Researcher Marcus Low said that while the research was encouraging, he advised caution when interpreting the results. “It’s good research and it’s encouraging that this kind of research was done in South Africa and by African researchers.
“There’s concern that it’s creating false expectations. It’s still early days, and we would advise caution when interpreting the findings,” he said.
National Association of People Living with HIV and Aids’ KwaZulu-Natal coordinator, Slungile Mntambo, said that while they supported the attempts of the researchers to find a method of protection that would benefit women, they would encourage further trials that would increase the effectiveness of the gel.