KHOPOTSO: The final study results were released by Dr Khatija Ahmed, one of three Principal Investigators involved in the research, during a telephone conference linking up researchers in Johannesburg, Cape Town and New York.
Dr KHATIJA AHMED: Carraguard was shown to be safe. However, it did not show to be effective against HIV. Although, there were fewer HIV infections in the Carraguard group, that is, a 134 than the placebo group that had 151 infections, the difference was too small and not statistically significant. The overall incidence was 3.5 infections per 100 women years. This was 3.7 infections in the placebo arm and 3.3 infections in the Carraguard arm.
KHOPOTSO: Carraguard is the first microbicide candidate to reach and complete a Phase III trial, during which stage scientists investigate whether a product is effective in protecting against infection. Although it has failed in that regard, Ahmed said the compound demonstrated a high safety profile.
Dr KHATIJA AHMED: It is the first Phase III trial to be completed with no safety concern, which is a major milestone for microbicides’ development. Carraguard has shown to be safe for long-term vaginal use, but not effective for HIV prevention. The safety finding of Carraguard is important because it’s using ingredients in the next generation of products that are being developed.
KHOPOTSO: The Carraguard trial, funded by the Population Council, began in March 2004 and ended in March last year and involved over 6000 women from three sites with high HIV infections in Gauteng, the Western Cape and KwaZulu-Natal. The Carraguard gel is made of Carageenan, a product made out of sea-weed. The trial was a randomised study. Half the participants tested the actual product and the rest were given a placebo, which had to be applied to the vagina for up to one hour before sex. All women were given condoms to use with the respective gels. A successful microbicide is viewed as the only remaining hope in female-controlled HIV prevention methods after the female condom.
Dr KHATIJA AHMED: We are disappointed with the trial results. However, we do not see this as a set-back for microbicide or HIV prevention research. A lot of knowledge and information has been gained from these trials, especially from this trial, in how to conduct trial designs’¦ We think that this is basically a stepping stone for us to improve research.
KHOPOTSO: Early laboratory testing showed Carraguard to be effective in blocking cells from becoming infected by HIV. In mice it protected against certain sexually transmitted infections. But this success could not be converted to humans. Dr Robin Maguire is the Director for Microbicide Development at the Population Council, in New York.
Dr ROBIN MAGUIRE: It’s very difficult for us in the laboratory to stimulate exactly the physiological events that occur in humans and we’re doing as best we can with growing cells and cultures and also looking at doing animal studies. Since there is no microbicide that is currently on the market ‘ proven and tested ‘ it’s very hard for us to know which of these assays that we use would be predictive of what occurs in humans.
KHOPOTSO: This is the third HIV prevention method to fail testing over the last year. The first was another microbicide trial based on cellulose-sulphate, followed by the MERCK candidate vaccine study. The truth is for as long as there is no cure for HIV infection it’s important to find other preventative measures to aid the condom. But if scientific efforts aimed at HIV prevention continue to disappoint, concern arises as to whether the goodwill of citizens, donors and governments can remain sustained in supporting such efforts.