Date: 14 December 2009
Source: Global Campaign for Microbicides
The Microbicides Development Programme released results of its large-scale effectiveness trial of PRO 2000, a candidate vaginal microbicide. The trial showed conclusively that PRO 2000 (0.5% concentration) was not effective at reducing women's risk of HIV. The trial was conducted in South Africa, Tanzania, Uganda and Zambia with over 9,300 women participating. Prior to the MDP 301 trial, PRO 2000 was found to be safe in a trial including women in Europe, the US, India and Africa. In February 2009, the release of promising results from another study testing the same product, HPTN 035, signaled that PRO 2000 might be effective. Unfortunately, MDP 301 showed that PRO 2000 use is not protective. It closes the chapter on the early generation of microbicides that were based on large polyanions thought to non-specifically block HIV from attaching to its target cells. This demonstrates the importance of investment in large-scale human clinical studies that can provide clear and definitive results about a product. The need remains urgent. Fortunately, researchers have begun work on a potentially highly potent generation of long-acting microbicide products containing antiretrovirals and formulated as long-acting vaginal rings, gels and films.
