Experimental Microbicide Gel Offers Some Protection Against HIV Transmission, Study Finds

An experimental vaginal microbicide gel shows a small level of protection against HIV transmission, according to a study presented Monday at the ongoing 16th Conference on Retroviruses and Opportunistic Infections in Montreal, Canada, the Washington Post reports (Brown, Washington Post, 2/10). The gel, called PRO 2000 and manufactured by Indevus Pharmaceuticals, is designed to prevent HIV from attaching to certain white blood cells. According to the study -- which primarily aimed to test the gel's safety -- the PRO 2000 gel is 30% effective in preventing HIV transmission. Although the findings might be inconclusive, the study is the first to demonstrate a possible beneficial effect from using microbicides (Stobbe, AP/Google, 2/9). Researchers for many years have worked to develop effective microbicides to prevent HIV transmission, but no earlier studies have shown promising results, and two previous trials showed that the gels being studied actually increased the risk of contracting HIV. According to the Post, because microbicides can be applied without the knowledge of sexual partners, they are considered "especially important in cultures where the subservient status of women makes it difficult for them to insist on abstinence or condom use" (Washington Post, 2/10).

For the study, Salim Abdool Karim of the Center for the AIDS Program of Research in South Africa and colleagues divided 3,100 women from Malawi, South Africa, the U.S., Zambia and Zimbabwe into four groups. They provided the first group of women with the PRO 2000 gel; the second with ReProtect's microbicide gel BufferGel; the third group with a placebo gel; and the remaining group with no microbicide gel. All the women received counseling to encourage condom use (AP/Google, 2/9). At the conclusion of the 20-month study period, 194 women had contracted HIV, including 36 women from the PRO 2000 group, 54 from the BufferGel group, 51 from the placebo group and 53 from the group that used no microbicides. Although the PRO 2000 gel was 30% effective, the researchers noted that the results are not statistically significant (Reichard, CQ HealthBeat, 2/9). According to the National Institutes of Health, which funded the study, an effectiveness rate of 33% would be statistically significant (AFP/Google, 2/9). The researchers also found no significant indication that BufferGel protected against HIV transmission (Fox, Reuters, 2/9).














Although the results of the Indevus trial show promise, the study did not provide data on the percentage of cases in which PRO 2000 was effective if actually applied. According to NIH, participants reported use of the gels in 81% of sex acts. Kathy Stover, NIH communications officer, said the study was based on self-reporting, and therefore the researchers "have no way to verify that the gel was actually applied prior to sexual intercourse" (CQ HealthBeat, 2/9). According to health officials, further research will be necessary to determine the gel's efficacy. London's Medical Research Council currently is conducting a study of the PRO 2000 gel involving 9,500 women, which is three times the size of the first study, Bloomberg reports. Mitchell Warren, executive director of the AIDS Vaccine Advocacy Coalition, said the "positive" result from the first trial "increases the anticipation of those from the next" (Lauerman, Bloomberg, 2/9).

Karim, who presented the PRO 2000 study at the conference, said the gel "could be a niche product for a group of women who have no other option." In sub-Saharan Africa, about 60% of HIV-positive people are women, the Post reports. (Washington Post, 2/10). Karim added that the study, "while not conclusive, provides a glimmer of hope to millions of women at risk for HIV, especially young women in Africa." Anthony Fauci, director of NIH's National Institute of Allergy and Infectious Diseases, added, "An effective microbicide would be a valuable tool that women could use to protect themselves against HIV and one that could substantially reduce the number of new HIV infections worldwide (AFP/Google, 2/9).


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