aids advocates demand rectal microbicides

aids advocates demand rectal microbicides
By Bob Roehr (ebar)

SOUTH AFRICA – April 28, 2006: Advocates are calling for research spending of $350 million over the next decade to develop rectal microbicides to prevent HIV infection. The challenge came Monday, April 24 at the start of the Microbicides 2006 conference in Cape Town, South Africa.

Most transmission of HIV occurs during sex. A microbicide could be applied prior to sex, perhaps as a lubricant, and use a variety of mechanisms to either kill the HIV virus or prevent it from entering the body. The most extensive work has been done with products designed for vaginal use. Several products are in advanced clinical trials and may become available as early as 2008.

In issuing the first ever report "Rectal Microbicides: Investments and Advocacy," the advocates noted that only $34 million has been spent in this area between 2000 and 2006, despite the fact that men who have sex with men comprise one of the groups most affected by HIV in the U.S. and Europe.

"Political marginalization and scientific challenges have sidelined investment into what could be a promising new prevention technology," the report stated.

It noted that heterosexuals also engage in anal intercourse and, "given the greater total numbers of heterosexual than homosexuals, it is estimated that the total volume of heterosexual unprotected anal intercourse is up to fivefold that of men who have sex with men."

Transmission of HIV is between 10- and 100-fold more efficient through anal rather than vaginal intercourse.

A microbicide that protects in the vagina may not protect when used in the rectum, and may even increase the risk of infection. That is because the compartments are very different in terms of their size, purpose, and the type of tissue involved.

The report says that at the very least, vaginal products need to be evaluated for rectal safety prior to moving into advanced clinical trials to determine their efficacy at preventing HIV infection. And ideally, rectal and vaginal efficacy trials should be conducted in parallel.

Ian McGowan, a researcher at the University of California, Los Angeles AIDS Institute and a co-author of the document, said the report is important because it "describes the current landscape of rectal microbicide research and helps define what resources will be needed to develop a safe and effective rectal microbicide."

The U.S. government, primarily through research at the National Institutes of Health, has been the leading funder of all work in the field of microbicides.

The report is available online at www.aidschicago.org/pdf/2006/adv_rectalreport.pdf