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New Research on Griffithisin and Carageenan to Prevent HIV and STIs Published in Nature Communications

September 24, 2018 – New research by the Population Council and partners shows that it may be possible to formulate a discreet, convenient, and woman-controlled multi-purpose technology to prevent HIV and other sexually transmitted infections (STIs) with limited risk of cross-resistance to antiretrovirals (ARV). This research published today in Nature Communications tests the non-antiretroviral agents, griffithsin (GRFT) and carrageenan (CG), in a fast-dissolving vaginal insert in rhesus macaques and mice.

HIV and STIs are two major threats to sexual health around the world. HIV is the leading cause of death among adolescent girls and young women in sub-Saharan Africa, and young women are far more likely to be living with HIV than men.

“New tools, policies, and programs that are based on the real life needs of women and girls are essential to preventing HIV and sexually transmitted infections,” said Nina Derby, scientist II at the Population Council’s Center for Biomedical Research and lead author of the study. “This study shows that a safe and effective on-demand product that prevents HSV-2 and HPV infections along with HIV could incentivize use, improve adherence, and decrease HIV incidence among women who are most at risk.”

Researchers combined griffithsin, a naturally occurring algae protein that inhibits HIV and other pathogens, including Herpes Simplex Virus (HSV-2), with carageenan, a highly potent anti-HPV algae-derived polysaccharide, into a fast-dissolving insert. The efficacy and pharmacokinetics of the combination product was tested in 10 rhesus macaques. They found that the GRFT/CG fast-dissolving inserts containing 1 mg GRFT and 3 mg CG protected 8 out of 10 macaques from simian human immunodeficiency virus (SHIV), a virus similar to HIV in non-human primates. In contrast, none of the macaques who received carrageenan-only fast-dissolving inserts were protected. The fast-dissolving inserts also protected mice from HSV-2 and HPV with similar efficacy as gel formulations of GRFT/GC.

Griffithsin, initially discovered at the Center for Cancer Research at the National Cancer Institute, is among the most potent anti-HIV agents described in the literature to date and can be produced relatively easily and inexpensively. Griffithsin has been found safe and effective when tested against HIV and HSV-2 in animal studies. A first-in-human Phase 1 clinical study of GRFT administered as a vaginal GRFT/CG gel is underway. Results are expected later in 2018.

This new evidence is a result of a close collaboration with researchers from the Aaron Diamond AIDS Research Center, Center for Disease Control and Prevention, Leidos Biomedical Research, Inc., National Cancer Institute, MPI Research, PATH, and the Tulane National Primate Research Center. It comes out of the Population Council’s Center for Biomedical Research, which is addressing some of the most pressing scientific challenges in sexual and reproductive health, including: HIV transmission, pathogenesis, and persistence – and factors that can interrupt it; how STIs such as HIV, HSV, HPV, and others interact to increase risks to women’s and men’s health; protective immune responses that could be manipulated to reduce the risk of infection or disease; and others.

Researchers are investigating new approaches to prevent HIV and other STIs, and developing next-generation contraceptives and innovative new multipurpose prevention technology products, or MPTs, which are designed to prevent HIV, other STIs and, in some cases, unintended pregnancy in a single product. The Center for Biomedical Research is developing these new tools as sustained-release formulations in rings, gels, tablets, fast-dissolving inserts, and other innovative delivery systems that are designed to be safer, lower-cost, and easier to use.

In August, the Population Council announced the U.S. FDA approval of Annovera™, a vaginal system to prevent unintended pregnancy. Annovera is the fifth contraceptive developed by the Population Council to be approved by the U.S. FDA. It is also the first one-year contraceptive fully under a woman’s control. For more information, please visit

Support for the Non-ARV-based Microbicide that Blocks HIV and Other STIs project is provided by the U.S. Agency for International Development, through the U.S. President’s Emergency Plan for AIDS Relief (PEPFAR) (USAID Cooperative Agreement number AID-OAA-A-14-00009).

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