What is a phase III vaccine trial?
Vaccine studies are done in phases. Click here to see how! The first two phases are small trials where the safety of the vaccine is determined, as well as the most effective dosage. In vaccine research, efficacy trials study how effective a vaccine is at protecting against a specific infection, at the best dosage and schedule in a given population. A vaccine is tested for efficacy in Phase III trials if it appears to be safe and shows some promise in smaller Phase I and II trials. VaxGen's experimental vaccine "AIDSVAXTM" was the first of all the HIV vaccine studies to move into a Phase III trial.

What is AIDSVAX?
AIDSVAXTM is a genetically engineered vaccine. The vaccine is not made from live HIV virus, but rather a protein from the surface of the virus (gp120) is copied through genetic engineering. The HIV surface proteins that are copied are from two different types of HIV that are common among viruses circulating in North America. The vaccine has no live virus, therefore there was no chance of AIDSVAXTM causing HIV infection. Some study participants may have tested indeterminate on standard HIV antibody tests as a result of receiving this vaccine. This was one of the reasons it was important for study participants to be tested only at the study site.

What did the VAXGEN Phase III trial involve?
The trial consisted of 5,000 participants in the United States and Canada, and 2,500 participants in Bangkok. Here in Seattle we enrolled close to 150 HIV negative men who have sex with men. The trial took three years from beginning to end and required 17 visits total from the participant. There was an immunization every six months for a total of seven injections. All records are confidential. Recruitment began October 1998 and we finished enrolling in September 1999.

What were the findings?
Initial results indicate that the AIDSVAX vaccine was not effective in preventing HIV in the overall group of vaccinated volunteers. VaxGen did report potentially higher levels of efficacy among non-Hispanic ethnic minorities (including African-Americans). More analysis is necessary before being able to draw any conclusions about the vaccine's effects in this subpopulation.

Though it is disappointing that AIDSVAX did not demonstrate efficacy in the study, the trial should not be characterized as a failed effort. Trial volunteers helped to show that a Phase III HIV vaccine trial is possible and that it is possible to recruit and retain a large number of highly motivated volunteers in this important step in HIV vaccine research. This trial and the important information being gathered from it would not have been possible without the time and dedication of the study participants. To quote Don Francis, President of VaxGen, "the trial volunteers are the real heroes."

How can I get more information?
If you have further questions about this or any of our research studies, feel free to contact us. You can also explore our links page for links to more information on the global search for an HIV vaccine. You can also click on the links below to read the abstracts of the journal articles that were written based on data gathered during the VaxGen study.

- Candidate HIV/AIDS vaccines: lessons learned from the World's first phase III efficacy trials (2003)

We are no longer enrolling for this study, but if you are interested in participating in HIV prevention research, please explore our research page that lists studies that we are currently enrolling for.

Thank You
to all of our
Vaccine Trial
Volunteers!

 
University of Washington/Seattle HPTU Site
Webpage: http://depts.washington.edu/hptu
Cabrini Medical Tower, 901 Boren Avenue
Suite 1300, Seattle, WA 98104
Campus mail: Box 359927
Fax: 206.520.3801
Tel: 206.520.3800