Experimental Gel To Protect Women From HIV Infection Not Effective, Study Finds

Main Category: HIV / AIDS
Also Included In: Women's Health / Gynecology;  Clinical Trials / Drug Trials
Article Date: 21 Feb 2008 - 7:00 PDT

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The experimental microbicide Carraguard, a seaweed-based gel that blocked HIV infection of cells in lab tests is safe but does not provide women with protection against HIV infection, according to results from clinical trials conducted in three locations in South Africa, the Seattle Post-Intelligencer reports (Paulson, Seattle Post-Intelligencer, 2/18). According to the AP/Google.com, the study's results are the "latest disappointment" in 20 years of attempting to develop a microbicide -- a cream or gel that women could use to lower their risk of HIV infection through sexual intercourse. A method of HIV prevention controlled by women is especially needed in developing countries because women often cannot persuade men to use condoms, the AP/Google.com reports.

The study of Carraguard was conducted from March 2004 to March 2007 in three South African locations. Carraguard is developed by the New York City-based not-for-profit Population Council. The microbicide was given to half of the 6,202 participants, and the remaining half was given a placebo. All study participants received safer-sex counseling and condoms. Women participated in the study from nine months to two years, with 4,244 completing the study. About 18% of the participants dropped out of the study, often because they became pregnant and Carraguard is not proven to be safe for use during pregnancy. An additional 13% of participants could not be found to gather follow-up information.

At the end of the study, researchers recorded 134 new HIV cases among women who used the microbicide, compared with 151 new cases among women given the placebo. Khatija Ahmed, principle investigator for the study, said the "results are comparable," with no statistically significant (Marchione, AP/Google.com, 2/18).

The Population Council noted the study participants "self-reported" using the microbicide gel in 44.1% of their sex acts. About 10% of the women said they used Carraguard 100% of the time, and 20% said they used the microbicide 75% of the time (Seattle Post-Intelligencer, 2/18). Barbara Friedland, a researcher at the Population Council who coordinated behavior studies in the trial, said that the "overall number [of adherence] is low, and it could have had an impact" on Carraguard's efficacy. It will take further analysis of the results to determine if patterns of condom use or failure to use the microbicide affected the outcome, the San Francisco Chronicle reports (Russell, San Francisco Chronicle, 2/19). The Population Council plans to continue testing Carraguard in combination with an experimental antiretroviral drug MIV-150, the Post-Intelligencer reports (Seattle Post-Intelligencer, 2/18).

The researchers also found that condom use among the study participants doubled from 33% of participants at the start of the trial to 64% during the trial. Other sexually transmitted infections decreased during the study, according to the AP/Google.com (AP/Google.com, 2/18).

Reaction

Henry Gabelnick -- executive director of Arlington, Va.-based Conrad, which halted Phase III trials of its microbicide Ushercell in Africa and India last year -- said that it "could still turn out, upon further analysis among those who used [Carraguard] more consistently, that there was a protective effect." Lori Heise, director of the Global Campaign for Microbicides, said, "We're all disappointed, but we're going to learn from this." She added, "A more important lesson to take away from this trial is to conduct future microbicide trials with greater attention to and emphasis on maximizing subject participation" (Seattle Post-Intelligencer, 2/18).

According to Reuters, because Carraguard was found to be safe, there are "hopes that it might be combined with drugs or other compounds to work better" (Fox, Reuters, 2/18). Jeff Spieler, an official at USAID, in a statement called the trial "groundbreaking work," adding, "We have always known that the path to developing a successful microbicide would be a long one" (AP/Google.com, 2/18). "Now we all have to redouble our efforts to develop a microbicide that women can use to protect themselves," Spieler said (Reuters, 2/18). The study was funded by the Bill & Melinda Gates Foundation and USAID (AP/Google.com, 2/18).

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