The pair of Phase 2b clinical trials run by the HIV Vaccine Trials Network (HVTN), which is headquartered at Fred Hutchinson Cancer Research Center in the US, and the HIV Prevention Trials Network (HPTN) have enrolled 4625 participants who are at risk for HIV infection from communities in the US, Brazil, Peru, Switzerland, and sub-Saharan Africa.
Complete enrolment will facilitate the timely analysis of the combined data of the AMP studies as well as trial-specific data, enabling researchers to answer the study questions efficiently.
The National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, is sponsoring and funding the trials.
The principal investigator of the HVTN, virologist and faculty member at Fred Hutchinson Cancer Research Center, Dr Larry Corey, said: “We are grateful to each study participant and their communities for making a commitment to participate in the AMP studies. Study participants are the heartbeat of our global clinical trials.”
While an experimental HIV vaccine aims to prevent infection by stimulating the immune system of an uninfected person to produce protective antibodies, a technique called passive antibody transfer involves giving antibodies directly to an uninfected person by injections or intravenous infusions.
The AMP studies are the most advanced human trials to test whether this strategy can prevent HIV infection in humans.
Study participants are receiving a “broadly neutralising antibody” named VRC01 every eight weeks.
Broadly neutralising antibodies, or bnAbs, can stop many strains of HIV from infecting human cells in the laboratory. Roughly 50% of people living with HIV make bnAbs naturally, but only after years of infection, when it is too late for the antibodies to have a protective effect.
Co-principal investigator and director of the University of North Carolina at Chapel Hill Institute for Global Health and Infectious Diseases, Dr Myron Cohen, said: “The development of bnAbs for HIV prevention and to identify targets for HIV vaccine design is a great example of how a concerted basic science programme and important clinical observations lead to new prevention technologies.”