WASHINGTON (Reuters) - A cream designed to protect women from the AIDS virus did not prevent infection, but it was safe, raising hopes that it might be combined with drugs or other compounds to work better, researchers said on Monday.
The product, called Carraguard, is the first HIV cream to be tested in advanced trials in women and shown to be safe.
"We are disappointed that this trial did not show Carraguard to be effective; nonetheless the completion of this trial is a milestone in HIV prevention research," said Peter Donaldson, president of the Population Council, which sponsored the trial.
"The trial has contributed significantly to the field's body of knowledge regarding product development, trial design, and women's and their partners' willingness to use a vaginal gel consistently."
Microbicides are products, such as gels or creams, that could be applied vaginally or anally to prevent transmission of the human immunodeficiency virus that causes AIDS.
So far, attempts to create a microbicide have failed.
The Carraguard trial began in March 2004 and involved 6,202 women in South Africa. Half got Carraguard, a tasteless, odorless gel made out of seaweed, and half got placebos.
All the women got counseling on how to prevent HIV and were also given condoms.
After three years 134 women using Carraguard became infected and 151 women given the placebo did. This difference was not statistically significant, the researchers said.
But Carraguard also did not worsen the risk of infection.
The two other microbicides to finish testing have in fact made women more likely to become infected -- a spermicide called nonoxynol-9 and a product called Ushercell, made by Toronto, Canada-based Polydex Pharmaceuticals.
"Now we all have to redouble our efforts to develop a microbicide that women can use to protect themselves," said Jeff Spieler, senior science adviser at the U.S. Agency for International Development.
In South Africa, more than 18 percent of the population is infected with the AIDS virus. Women account for 55 percent of HIV-positive adults there, almost all of them infected by men during sex.
Experts agree women need a product they can use to protect themselves because many men refuse to use condoms.
More than 33 million people globally are infected with HIV, which is incurable and deadly. There is no vaccine and drugs that can help control the infection do not stop its spread and are not available to most people.
Other products being developed as microbicides include Gilead Science's tenofovir gel, a gel called PRO 2000/5 and Pfizer Inc's newest HIV drug maraviroc.
Reporting by Maggie Fox, editing by Todd Eastham