October 12, 2017—The Population Council today announced the enrollment of the first participant in the Phase I clinical trial evaluating PC-6500 (griffithsin in a carrageenan gel), an investigational multipurpose technology to prevent HIV and sexually transmitted infections (STIs), two major threats to sexual health around the world. This is the first in-human study of griffithsin (GRFT), a naturally occurring algae protein that inhibits HIV and other pathogens, including Herpes Simplex Virus (HSV-2).

“Multipurpose products that prevent sexually transmitted infections, including HIV, must be a research and development priority,” said James Sailer, vice president and executive director of the Center for Biomedical Research at the Population Council. “We are excited to be enrolling participants in the first trial of a griffithsin-containing multipurpose prevention technology, which could be an important addition to the HIV and STI prevention toolbox.”

PC-6500 is an investigational MPT comprised of griffithsin (GRFT) in a carrageenan gel. The goal of the trial is to assess the safety, pharmacokinetics (PK) (how the body processes the compound) and pharmacodynamics (PD) (how the body is affected by the compound) of PC-6500 to support the further development of GRFT as an MPT to prevent HIV and STIs for on-demand or sustained use.

The trial is being conducted at Albert Einstein College of Medicine in the U.S., and 27 women aged 18–49 will be enrolled. Results are expected in 2018. Seven women will participate in an open-label period receiving a single dose of PC-6500; data from this trial will inform the randomized, placebo-controlled safety, PK and PD assessment of PC-6500. Twenty women will be randomized to receive either PC-6500 or a placebo and will use the gel once daily for 14 days.

Griffithsin, initially discovered in the Center for Cancer Research at the National Cancer Institute, is the most potent anti-HIV agent 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.

“Griffithsin’s mode of action and the fact that it is not used in HIV treatment means there is no risk that users of a griffithsin-prevention product could develop cross-resistance to ARVs that are used for treatment,” said George Creasy, medical director at the Population Council’s Center for Biomedical Research. “This may increase the possibility that a griffithsin multipurpose prevention technology could become an over-the-counter product and increase access for people in high-demand, low-resource settings.”

Population Council scientists are pursuing multiple delivery systems for GRFT, including fast-dissolving inserts and intravaginal rings to provide on-demand and sustained protection. Additional delivery systems may be developed in the future. 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).

The Population Council is working to help women and men worldwide avoid HIV, other STIs, and unintended pregnancy. HIV infection is the leading cause of death among women aged 15–44. HSV-2 infects more than 500 million people around the world.