Research Triangle Park, NC and Huntingdon Valley, PA -- International efforts are underway to evaluate microbicides as a tool to prevent HIV infection in people at high risk. As part of this initiative, with funding from the U.S. Agency for International Development (USAID), Family Health International (FHI) and Cellegy Pharmaceuticals, Inc. have been working to see if a vaginal gel called Savvy is effective in preventing male-to-female transmission of HIV among women at high risk of infection in West Africa. Other organizations are conducting trials in the United States to determine if Savvy is effective as a contraceptive.
Family Health International and Cellegy Pharmaceuticals announced today that they plan to stop the HIV prevention trial of Savvy being conducted by FHI in Ghana. This decision followed a recommendation of the study's external, independent Data Monitoring Committee (DMC). The DMC reviewed the study data to date and concluded that, while there is no evidence of safety concerns based on the comparative HIV infection rates in the Savvy and placebo groups, the Ghana study would be unable to evaluate the effectiveness of the product.
The Savvy Phase 3 clinical trial in Ghana began recruitment in March 2004 and completed planned enrollment with 2,142 women in June 2005. Half of the women were given Savvy gel, and half were given a placebo gel to be inserted vaginally with pre-filled applicators. At monthly visits during each woman's year-long follow-up, each participant was tested for HIV and reported on use of the gel and any side effects or medical problems. Each participant received counseling for reducing her risk of HIV and was given condoms for use during all sexual acts. Eighteen months into the study, the observed HIV incidence in the cohort was about one-third the rate expected prior to the study.
"The reason we decided to stop the trial was that the group of women who volunteered to participate had such a low incidence of HIV that there was no way for this study to show whether use of Savvy, compared with a placebo gel, would prevent HIV or not," says Dr. Leigh Peterson, principal investigator of the Ghana study and senior scientist at FHI. "Perhaps because of study procedures such as risk-reduction counseling, condom provision, or other factors, most study participants have been able to avoid infection. This is a public health success, but such low incidence means the study could no longer answer the question about product effectiveness."
"Stopping the trial does not mean the product is ineffective against HIV, but rather that we cannot make any conclusion about product effectiveness using this protocol in this population," Peterson added. "The additional costs and time required to obtain adequate data on HIV infections among study participants would not be warranted given the low HIV seroconversion rates. Those resources would be better spent in locations with higher HIV incidence."
Most importantly, the DMC concluded that there was no evidence of safety concerns with regard to Savvy, based on a review of the comparative numbers of HIV seroconversions in the Savvy and placebo groups, and other interim data. The Ghana Savvy study can at this point be considered a successful safety study.
FHI, Cellegy, and USAID are continuing this important research in Nigeria where a second Savvy study is under way, in the hopes of finding an answer to the question of product effectiveness for HIV prevention. Consideration will be given to expanding the ongoing Nigeria study, if necessary after an interim analysis is completed, and/or beginning a new trial in locations with higher HIV incidence.
Should an effective microbicide become available, all the parties are committed to returning the benefits of research to the communities where the studies were conducted, including Ghana and Nigeria. Effective HIV prevention tools should be available to everyone, especially the volunteers who have helped by their participation in this study.
Contraception trials of Savvy being conducted by other organizations in the United States with the support of the National Institutes of Health will continue as planned. Enrollment is continuing in the comparative contraception study at numerous sites in the U.S., and planning is underway for a second study for contraception, also in the U.S. Additional studies to examine Savvy's effectiveness against other sexually transmitted infections, including herpes, are planned in the near future.
FHI looks forward to continuing to work with partners on studies of Savvy and other microbicides with the potential to help prevent HIV.
Microbicide trials are critical to identifying new HIV prevention tools to reduce the number of individuals who become infected with HIV worldwide. Heterosexual contact accounts for more than 70 percent of all HIV infections worldwide. Correct and consistent use of male condoms has been shown to prevent HIV infection, but women are often unable to negotiate condom use with their male partners. This study is important because a woman-controlled method, such as a topical gel, would be an important addition to current preventive methods.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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