Microbicide Excitement and Reality in 2010
Day Three in Vienna and the hot news is the results of the microbicide study in South Africa, known as CAPRISA. There was an energy and excitement in the air and the crowd at the presentation was so large that it had an equally large overflow room, also filled to capacity. People stood and gave a long standing ovation after the presentation, even in the overflow room. I note this because in that room we were applauding a PowerPoint ... that's a lot of excitement! Now don't get me wrong, this study is a major breakthrough along the complicated path to women controlling their risk for HIV infection, but let's think about the reality for a couple of minutes.
CAPRISA 004 was a double-blind, randomized controlled trial (meaning half of the participants received the vaginal gel with Tenofovir -- an antiretroviral -- and half received a placebo vaginal gel). It enrolled 889 HIV-uninfected women at two sites in South Africa. While the overall reduction in HIV risk was 39%, there was a trend toward higher effectiveness -- a 54% reduction -- among women who reported the best adherence to product use. Analyses for safety identified no significant concerns. The vast majority of the participants (97.4%) found the gel acceptable (i.e., not irritating or sloppy, etc). That's great news! Women were on product on average 18 months and study retention was 95.2%. That means 95% of women came in for regular study visits where they were interviewed and reminded about gel and condom use. With that, regular and consistent condom use, including condom use at last intercourse was equal in both groups, about 30%. Meaning that regular and consistent condom use was less frequent for 70% of women on study. The study also indicated that use of the gel reduced the risk of herpes virus (HSV) by 51% among women participating in the trial. This is an interesting observation that will be important to investigate further, not only to prevent HSV on its own, but also because of the role that genital ulcers play in increased HIV transmission.
The next step is a study called VOICE (nice name) that has already started enrolling 5,000 women in Southern African countries, looking further at the Tenofovir gel and includes looking at PrEP, pre-exposure prophylaxis (taking oral antiretrovirals before a possible HIV exposure).
So here are the things I wondered about as I heard the study summary: I wondered what success rate would a gel need to have to be approved for use in the United States. Would the FDA accept a rate here that would be meaningful in high-incidence areas of the world? Would the FDA approve a gel for use in the United States that had a 39-54% success rate? How long will it take to get the new information? The good news is the CAPRISA study was complete in two and a half years -- that's super quick for research -- but the next study will take at least that long and then who knows if that will provide enough evidence for approval, or if more studies are needed.
The other thing to think about was this gel was used with condoms, not 100% of the time, but condom use was part of the equation. Our prevention strategies for girls and women will still need to revolve around empowerment, including condom negotiation. Additionally, we who work in the field will need to make sure that the message is clear: this was a research finding, not yet an available product and not connected to currently commercially available gels. We know women, especially young women, are desperate for something to protect them that they can control. It's just not here yet. Hopefully, microbicides will be a part of the prevention tool kit in the coming years, and that will include the toolkit for women in the United States. But it's a toolkit, not any one single magic bullet.
To quote Dr. Fauci from the NIH: "The CAPRISA 004 study is an exciting scientific achievement that moves us one step forward to gaining another effective tool to prevent HIV infection. However, because no one approach will be appropriate or acceptable to all, we must continue to pursue a range of HIV prevention modalities, including microbicides, pre-exposure prophylaxis (PrEP), and vaccines, as we simultaneously pursue scientific strategies designed to bring us closer to finding a cure for HIV/AIDS." (Underline and bold emphasis is mine.)
Founded in 1994, AIDS Alliance for Children, Youth & Families (AACYF) is a national non-profit organization whose mission is to advance the partnership between consumers and providers -- they are the voice of women, children, youth and families living with and affected by HIV/AIDS. AACYF works to enhance and expand access to quality, comprehensive, family-centered care to America's women, children and youth affected by HIV/AIDS. For more information on AIDS Alliance, visit www.aids-alliance.org.