A major study of an HIV prevention microbicide was halted this week after it was discovered that women receiving the microbicide were more likely to become infected with HIV than women receiving the placebo. A second study of the same product has been stopped as a precaution.

Several other products remain in large-scale studies that are due to report in 2008 or 2009. These studies share a number of challenges that were highlighted at the Microbicides 2006 meeting in Cape Town last year. These include poor adherence, the high rates of pregnancy seen in one of the trials halted this week, and the potential confounding effect of sexually transmitted infections on the results of these studies.

This is the second large microbicide study to be halted in less than a year, and the news should remind us that it is best not to be over-confident about the potential of biomedical interventions like microbicides and pre-exposure prophylaxis to offer important new ways of reducing HIV infection rates in the near future

Phase III Trials of Microbicide Carraguard Underway, Expected To Be Completed by March 2007
http://www.kaisernetwork.org/daily_reports/rep_index.cfm?DR_ID=41621

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Summaries and Press Releases

International AIDS Society Statement on Announcement that Two Phase III Trials of HIV Microbicide Candidate Ushercell Have Been Halted


1 February 2007, Geneva, Switzerland - The International AIDS Society (IAS), the world's leading independent association of HIV professionals, acknowledges today's announcement that two Phase III trials of Ushercell (a cellulose sulfate based topical gel being testing for HIV prevention in women) have been halted due to preliminary results at some sites indicating potential increased risk for HIV among women who use the compound. The findings of increased risk were identified at some sites in a trial sponsored by CONRAD, a cooperating agency of USAID administered through the Department of Obstetrics and Gynecology at Eastern Virginia Medical School in the United States. The CONRAD trial was being conducted in South Africa, Benin, Uganda and India. While emphasizing the urgent need for the timely development of an effective microbicide to protect women from HIV infection, the IAS also recognizes the utmost importance of safety, and applauds the decision to halt the studies to evaluate the
preliminary findings.

Family Health International, sponsor of the second halted trial in Nigeria, had not found similar results but halted the trial as a precautionary measure, given the preliminary results in the CONRAD trial. At this point, it is not clear why the use of cellulose sulfate was associated with increased risk for HIV infection among women in the CONRAD-sponsored trial. Earlier trials of the same compound involving 500 participants did not indicate safety concerns.

"While extremely disappointing, this setback is also an opportunity to learn why some women who used Ushercell were found to be at increased risk of HIV infection," said Dr. Pedro Cahn, President of the IAS and Director of Fundación Huesped in Buenos Aires, Argentina. "This will strengthen future microbicide research and increase our overall knowledge of how such compounds work."

"The importance of developing a safe and effective microbicide to protect women from HIV infection cannot be understated," said Dr. Cahn. "We must give women the tools to protect themselves, independent of their partners' actions."

The halted trials were two of six Phase III microbicide trials underway at the start of 2007. Four additional Phase III trials of other candidates are ongoing.

Further data on microbicides and other biomedical prevention tools will be discussed during the upcoming IV IAS Conference on HIV Pathogenesis, Treatment and Prevention in Sydney.



About the IAS
The IAS is the world's leading independent association of HIV professionals, with over 10,000 members in 171 countries. IAS is the principal organizer of the International AIDS Conference and in July 2007 will host the 4th IAS Conference on HIV Pathogenesis, Treatment and Prevention in Sydney, Australia ( www.ias2007.org  ).
 

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