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PROGRAM History of Research, 1989–Present and Beyond The Population Council was one of the first organizations to begin a major effort to develop vaginal microbicides, products that would enable women to protect themselves against sexually transmitted infections (STIs), particularly HIV. The Council's microbicides program draws on the wide range of expertise among its biomedical, public health, and social science researchers in its New York headquarters and its offices around the world. Biomedical researchers work on basic research on HIV transmission and toward developing new potential microbicides, including contraceptive formulations. Social scientists have investigated women's preferences for particular vaginal formulations, educated policymakers about the need for woman-initiated methods, and addressed important questions of trial design. In 1989, Council biomedical researchers started basic science research on the sexual transmission of HIV and began screening compounds for potential microbicidal activity. Using models both in laboratory tests and in animal systems, scientists examined a variety of compounds for activity against HIV and other sexually transmitted pathogens. Compounds called sulfated polysaccharides stood out as especially promising. One, carrageenan, proved far more effective at protecting mice from infection than any other substance tested. Armed with this information, Council scientists honed promising carrageenan-based microbicide formulations and moved them through the product-development process, aiming to develop a microbicide that would be widely available, stable in tropical climates, and affordable even to the world's poorest women. This work resulted in the development of the Council's first candidate microbicide, Carraguard®, which is derived from carrageenan. Carrageenan has been used for decades as a thickening agent in many products, including infant formula, soups, and ice cream. Beginning in 1996, the Population Council conducted a number of Phase 1 safety and acceptability trials of carrageenan-based candidate microbicide gels for vaginal use in healthy, HIV-negative women in six countries, including the United States. Overall, the women found the gel acceptable, and none experienced significant irritation of the reproductive tract. A study conducted among HIV-negative couples in Thailand showed that Carraguard was safe and acceptable for men as well. In South Africa and Thailand, 565 healthy, nonpregnant, HIV-negative women participated in expanded safety and acceptability trials of Carraguard. The Council oversaw the clinical trials, which were implemented by the University of Cape Town (UCT), the Medical University of Southern Africa (Medunsa), and the Thailand Ministry of Public Health–US Centers for Disease Control and Prevention Collaboration. Study participants were instructed to apply the gel at least three times per week and before each act of vaginal intercourse. The women received safer-sex counseling, testing for and treatment of curable STIs, and free condoms. They returned to the clinic for monthly pelvic exams and interviews about Carraguard use and acceptability. In these studies, Carraguard was found to be safe. The large-scale, long-term Phase 3 trial to test the efficacy and safety of Carraguard began in South Africa in March 2004. The Council conducted the trial in collaboration with three South African institutions: the Medical Research Council, the University of Limpopo/Medunsa campus, and the University of Cape Town. The randomized, double-blind, placebo-controlled trial among nonpregnant, HIV-negative women completed data collection in early 2007. It found the product to be safe for vaginal use. The trial did not demonstrate that Carraguard is effective in preventing male-to-female HIV transmission during vaginal intercourse. What Comes Next (continued)Locations Australia, Brazil, Burkina Faso, Chile, Dominican Republic, India, Kenya, Senegal, South Africa, Thailand, Zimbabwe, United States See Also
Contact: microbicide@popcouncil.org
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