???Better than a Condom???? may have left readers with some incorrect impressions related to microbicides research to date.
Microbicides research and development efforts were initiated in the late 1980???s in response to the urgent need expressed by women for something to help prevent HIV that they themselves could control. At the Population Council, the earliest research and development efforts were by scientists in our contraceptive development laboratory (not by virologists, as stated in the article). Formulations were based on products already in use as contraceptives and lubricants, such as gels, since their acceptability to women and their partners was already established.
Early in the development of Carraguard, Population Council scientists conducted formulation preference research among women in Thailand, Africa, and the United States. Acceptability research also figured prominently in early Phase 1 and 2 trials of Carraguard, conducted in Thailand and South Africa among more than 500 women. The majority of the women in those trials said they would use Carraguard gel if it were available as a microbicide.
Knowledge gained in the first generation of trials was extremely valuable for moving the microbicides field forward. For example, the results of our completed Carraguard trial were different from those of the trials of two other sulfated polysaccharide products that had seemed similar during pre-clinical and early Phase 1 testing. The Carraguard trial did not find a significant protective effect, that of CS indicated potential harm, and that of PRO 2000 saw encouraging signs of possible efficacy, although their results were not statistically significant. (Findings from a larger trial of PRO 2000 are expected by year-end). Based on these findings, scientists are working to identify the specific characteristics of these three compounds that may have led to the differences.
Biomedical and social scientists at the Population Council and throughout the microbicides field continue to advance our knowledge, working on basic research on HIV transmission, testing a range of promising products to prevent HIV infection, and improving the adherence and accuracy of reporting for future clinical trials.
Medical research is seldom simple or quick. However, the microbicides field has grown tremendously, and the involvement of scientists from a wide range of disciplines makes it all the more likely that we will in the end find an effective product.
--Barbara Friedland and Melissa May, Population Council; www.popcouncil.org/microbicides
Better than a Condom?
New research clears a path for an effective HIV-blocking gel, but several obstacles still remain.
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A new, more-promising iteration of the long-heralded HIV-blocking vaginal gel may one day become a reality, according to a study published online yesterday in the journal Advanced Functional Materials. But as the dream product crawls towards the marketplace, scientists worry that the biggest challenge—getting women to actually use it, or any gel like it—still lies ahead.
Unlike previous versions of microbicide, the latest gel functions more like an actual condom. It's applied via applicator in the hour or so before sex and turns semisolid in the presence of semen, physically blocking HIV (and theoretically, other viruses and semen, too) from moving through the vagina in the first place. (The gel dissolves after sex.) "It's the first microbicide of its kind," says Patrick Kiser, a bioengineer at the University of Utah and the study's lead author. "It prevents the virus from even touching the vaginal tissue." The novel polymer concoction could see its first clinical trial in three years and if all goes well, be available for widespread use a few years after that.
The need for HIV-prevention methods that women can control is undeniably urgent. Women account for half of all HIV infections globally; in sub-Saharan Africa, where the disease is most prevalent, they make up 60 percent of cases. The reason is simple: women in the region lack the power to compel their sexual partners to wear condoms. For a decade now, scientists have been working to develop an HIV-blocking vaginal gel, a microbicide often called a molecular condom. This form of protection could be employed without the consent of a partner and has long been seen as the best hope for empowering women to protect themselves.
But, like any effort to bring high-tech innovation to resource-poor settings, progress has been slow. In 2007, one large-scale clinical trial was terminated early when the substance—cellulose sulphate—appeared to actually increase the risk of HIV infection. Another early contender, developed in an American lab, failed to hold up in the warmer African climate (it turned from a usable gel into a messy ineffective liquid). And Carraguard, a gel derived from seaweed extract, made it all the way to phase III clinical trials only to be abandoned late last year when results showed that it was not effective at preventing HIV: the gel was safe, but its difficult to say how well it worked because study participants only used it 40 percent of the time.
The failure underscored what has become a common complaint among some factions of global health workers: high-tech solutions that come from Western labs often fail to account for on-the-ground realities. "There are numerous personal and cultural reasons why a microbicide may or may not be used," says Kate Morrow, a behavioral psychologist at Brown University who has collaborated with Kiser. Failure to consider those factors may have doomed some projects from the start.
In the case of Carraguard, it's not clear exactly what went wrong, but David Katz, a biomedical engineer and gynecology professor at Duke University thinks the effort to design a molecular condom has been plagued from the start by a lack of intellectual diversity. "It's a tough problem because sex is complicated, messy, and differs culturally in surprising ways," he says. "Microbicide research has been dominated by virologists, but if you really want to solve the problem, you need engineers and psychologists, as well."
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