http://www.businessday.co.za/articles/topstories.aspx?ID=BD4A935915

Results from the HPTN 035 clinical trial released yesterday suggest the microbicide PRO 2000 is partially effective against HIV infection, but more research is needed to be sure.

Microbicides are gels or creams that are placed in the vagina before sex in the hope of preventing male to female HIV infection. They can also be used rectally. Scientists hope microbicides will offer women a discreet way to reduce their risk of contracting HIV from an infected partner, particularly in situations where men are reluctant to use condoms.

With good research infrastructure and more than 5,7-million people infected with HIV, SA is at the forefront of microbicide research.

After years of disappointing clinical trials, scientists in the HPTN 035 trial said they were delighted to report some good news yesterday.

"For the first time in the history of microbicide research we've found a product that looks very promising," said the study's principal investigator, Prof Gita Ramjee, a scientist at the Medical Research Council (MRC). "It's a big plus for the prevention field as a whole, as trials have been falling like dominoes," she said.

Recent failures include products that at best had no effect at all, such as Carraguard, or worse, appeared to do harm, such as Ushershell. There has also been bad news on the HIV vaccine development front, after the failure of Merck's candidate AIDS vaccine.

The HPTN 035 phase 2 study involved 3099 women in SA, Zimbabwe, Malawi, Zambia and the US. It was funded by the US National Institutes of Health and tested the safety and efficacy of two candidate microbicides, PRO 2000 and BufferGel (developed by US firm ReProtect). Previous laboratory and animal tests showed PRO 2000 stopped HIV from entering the cells of the vagina, while BufferGel boosted the vagina's natural acidity to disactivate HIV and other pathogens.

Women were randomly assigned to four groups and received BufferGel, PRO 2000, a dummy gel with no active ingredients, or no gel at all. They were counselled about safe sex and provided with free condoms.

There were a total of 194 HIV infections among the women: 36 among women who used PRO 2000, 54 among those who used BufferGel, 51 among those who used the placebo, and 53 among participants who used no gel at all.

Analysis of the data showed PRO 2000 was 30% effective against HIV infection, but the results were not statistically significant, said the study's protocol chair, Prof Salim Abdool Karim. This means it is possible the results were simply due to chance. However, scientists were fairly confident that the gel had provided some protection, as further analysis showed women who used it a lot were better protected than women who hardly used it, said Karim