Products are currently in development, but as they approach the point where large, costly phase 3 clinical trials are needed, additional funding and political support are critical to helping microbicides reach the people who need them, advocates say.

"It's a very large effort that needs the support of countries to be able to move forward," Zeda Rosenberg, CEO of the International Partnership for Microbicides, told United Press International.

Microbicides currently in studies use one of several mechanisms to prevent women who are exposed to HIV from becoming infected. They are applied directly to the vagina in the form of a gel, cream, sponge, suppository or vaginal ring and offer the potential to drastically slow the spread of the disease among women, who are more susceptible than men for both physiological and social reasons.

Unlike condoms, which require the consent of a male partner for use, microbicides use can be controlled by women. That fact could save millions of lives in places where women do not have the ability to refuse sex with their husbands or insist on condoms. Condoms are also not an option for women trying to become pregnant.

More than half of HIV cases in sub-Saharan Africa are now among women ages 15 to 49, and most are married to their lifetime sexual partner. In India, 22 percent of HIV cases are in housewives with a single partner.

"Marriage and motherhood are becoming HIV risk factors in many places," Rosenberg said.

The U.S. government is already the world's largest funder of microbicide research, allocating more than $101 million in 2005, followed by the Bill and Melinda Gates Foundation and the British government.

But in order for promising ideas to become marketable drugs, they must undergo large-scale drug trials involving thousands of individuals on several continents.

To maintain research momentum and speed microbicides to market, the world's funding for research must increase from $160 million in 2005 to $280 million in 2006 and the subsequent five years, Rosenberg said.

There are currently 10 products under active development in pre-clinical trials, 16 in clinical trials and five in large-scale efficacy trials. In all, some 20,000 women around the world will be participating in such trials over the next three years.

Carraguard, which is being tested in South Africa with funding from the Population Council, Gates Foundation and USAID, uses an extract from carageenan, a seaweed often used as a food additive, to alter the acidity of the vagina to prevent infection by HIV and other sexually transmitted diseases.

Cellulose sulfate is undergoing two concurrent trials, one in Nigeria and one spanning Burkina Faso, Uganda, India, Kenya and South Africa, with funding from the Global Microbicide Program, Gates Foundation and USAID.

Indevus Pharmaceuticals is testing its PRO 2000 product in South Africa, Uganda and Tanzania.

BufferGel, a vaginal defense enhancer that affects the acidity of the vagina, is being developed by ReProtect and under testing in southern Africa, with support from the NIH.

Cellegy Pharmaceuticals is testing a membrane disruptive agent called Savvy in Nigeria with the support of USAID and several NGOs.

At a recent congressional briefing, Sen. Barack Obama, D-Ill., and others called for the government to increase its investment.

"We are so close (to a microbicide) at this point that the question everybody is asking is no longer if, but when ... and the moment can't come too soon," said Obama, who is the leading Democratic sponsor of the Senate version of the Microbicide Development Act, a bill that would increase funding for research and create infrastructure at the National Institutes of Health, Centers for Disease Control and USAID.

"It could make all the difference in women's lives. It could give them control of their well-being," he said, both in developing countries and in the United States. "It's time now for the federal government to step up."

Part of the urgency comes from the fact that once trials have been completed, means must be found to distribute microbicides to the developing world where they are most needed -- a process that historically has taken decades, Rosenberg said.

While phase 3 trials are always difficult, microbicide trials pose additional challenges, said Salim Abdool Karim, director of the Centre for the AIDS Programme of Research in South Africa.

In such a trial, women are provided with test products, and then researchers must wait to measure if they eventually contract HIV or not, he said. Ethically, such trials must then have resources available for infected patients.

Women participating in microbicide trials must attend 29 study visits, compared to 16 for HIV vaccine studies, and undergo 11 pelvic exams over two years.

In addition, about half of women who arrive to register for trials turn out to be already infected with HIV. These women also need treatment options, Obama said, and all trial participants need to be educated about other ways of avoiding infection.

But the potential impact on women in South Africa -- and worldwide -- makes it worth the effort, he said.

"In South Africa, Saturday has become the day when you go from funeral to funeral of young women. There are many products coming through the pipeline. We need the ability to test them."

Related Links
the missing link