Carraguard Ineffective for Preventing HIV Transmission, Study Finds; Researchers Say That Microbicide Research Should Continue
The experimental vaginal microbicide Carraguard is not effective for preventing male-to-female HIV transmission, but researchers should continue efforts to develop a female-controlled HIV-prevention method, according to a study published recently in the journal Lancet, the Press Association reports. For the Phase III study, researchers Stephanie Skoler-Karpoff and Barbara Friedland assessed the efficacy of Carraguard, a compound developed by the Population Council based on carrageenan extracted from seaweed (Stone, Press Association, 12/4). Microbicides include a range of products -- such as gels, films and sponges -- that could help prevent the sexual transmission of HIV and other infections.
For the study, conducted from March 2004 to March 2007 in the South African locations of Gugulethu, Isipingo and Soshanguve, researchers gave Carraguard to half of the 6,202 participants and a placebo to the remaining group. 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 (Kaiser Daily HIV/AIDS Report, 2/20). Although the results of the study were published in the Lancet on Saturday, researchers announced the results of the study in February (Population Council release, 12/5).
At the end of the study, researchers recorded 134 new HIV cases among women in the Carraguard group and 151 HIV cases among women in the placebo group. In addition, the researchers found no significant difference in the time taken for a woman from either group to test HIV-positive. According to the authors, the study "did not show Carraguard's efficacy in prevention of male-to-female transmission of HIV, although no safety concerns were recorded" (Press Association, 12/4). According to the study, Carraguard is safe for vaginal use when used an average of once weekly for up to two years (Population Council release, 12/5). The researchers added, "Low levels of gel use could have compromised the potential to detect a significant protective effect."
Although the authors called the results from the Carraguard trial and other microbicide efficacy trials "disappointing," they add that "the search for female-controlled HIV-prevention methods must continue." Willard Cates and Paul Feldblum of Family Health International in a commentary piece accompanying the study wrote that "no single approach" to HIV prevention "will suffice," adding that "partly effective prevention approaches" should be "bundled into packages targeted to specific populations." According to Cates and Feldblum, bundled approaches could include behavioral, biomedical and structural interventions that reinforce each other. "The cumulative influence of combination prevention is our hope for thwarting the spread of HIV," Cates and Feldblum write. According to the Press Association, women account for 61% of HIV cases in sub-Saharan Africa, the region with the highest HIV/AIDS burden worldwide. In addition, among people ages 15 to 24, women account for 90% of new HIV cases (Press Association, 12/4).
An abstract of the study is available online. An extract of the accompanying commentary also is available online.