HIV-vaccine trial: Moving forward in Africa

Collaborators in the United States and South Africa have begun Africa's first large-scale HIV-vaccine trial

Photo by Stephanie Cartier Dr. James Kublin, of the HVTN, is one of the study's lead investigators. He is also a staff physician in the Clinical Research Division.

The first large-scale HIV-vaccine trial on the African continent is now under way in South Africa, where 5.5 million people live with the deadly virus. Led by scientists from the Hutchinson Center and South Africa, the trial is called Phambili, or "moving forward" in the Xhosa language. It is expected to run four years and enroll up to 3,000 participants at five sites throughout South Africa.

The sites are part of the HIV Vaccine Trials Network (HVTN), which is based at the Center and supported through a cooperative agreement with the National Institute of Allergy and Infectious Diseases of the National Institutes of Health. The Center's Statistical Center for HIV/AIDS Research and Prevention is the statistical data management center for the study. The trial sites also receive funding from the South African AIDS Vaccine Initiative.

"This trial will answer several major scientific issues that face all of us in the field of HIV-vaccine development," said the Center's Dr. Lawrence Corey, principal investigator of the HVTN. "It will determine the usefulness of vaccines that induce high immune response to the parts of the virus that are similar between different strains of HIV-1."

The study is known as a phase IIb or "test of concept" efficacy trial because it enables researchers to determine whether the test vaccine prevents HIV infection, results in lower HIV levels in those who become infected after vaccination or both.

Additionally, the study is likely to provide important new data on how the test vaccine might work in a predominantly heterosexual HIV epidemic, how well the vaccine works in women, and whether the vaccine works in populations with pre-existing immunity to the viral vector used in the vaccine.

"South Africa is an excellent location for this trial due to the high levels of infection coupled with the good clinical infrastructure, including internationally recognized immunology laboratories, a well-established national vaccine initiative and experience in running clinical trials," said Dr. James Kublin, one of study's lead investigators with the HVTN and the Clinical Research Division. He also said the community involvement and educational initiatives needed to move a trial of this scope forward are strong. The Phambili trial will enroll healthy HIV-negative males and females, aged 18 to 35 years, who are sexually active and not pregnant.

Merck Research Laboratories developed the test vaccine, known as the MRKAd5 HIV-1 trivalent vaccine. In multinational phase I and phase II trials, the vaccine, which does not contain live HIV and cannot cause infection, was found to be safe and stimulate cellular immune responses against HIV in more than half of volunteers.

To learn more about the study, read the news release posted on the HVTN Web site at www.hvtn.org/media/pr/phamfr.html.

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