VaxGen Clinical Trials

Vaccines have to pass three stages of testing in humans before they can be licensed by the U.S. Food and Drug Administration for manufacture and marketing.

  • Phase I — tests for safety and dosage
  • Phase II — larger-scale tests for safety and determination of whether the vaccine stimulates antibodies and immune memory
  • Phase III — large-scale, placebo-controlled, double-blind tests to determine how well the vaccine is working. These tests must be performed in thousands of individuals who are HIV-negative but at high risk of contracting the disease.

Phase I/II
AIDSVAX® has been tested in two series of Phase I and Phase II clinical trials, both of which showed that that AIDSVAX appears safe and produces antibodies in virtually everyone who receives the vaccine. The first series, which was conducted by Genentech, demonstrated that the initial formulation of the vaccine appeared safe. Moreover, all of the vaccinated participants in Phase II produced antibodies in their blood that neutralized the HIV strain that the vaccine was designed for.

In a second series of Phase I/II tests, AIDSVAX was reformulated so that it included gp120 from two strains of HIV, instead of just one. Two formulations of the vaccine were tested, one in Thailand and one in the United States. As with the earlier version of the vaccine, this new bivalent vaccine appeared safe. Moreover, subsequent research demonstrated that the bivalent formulations improved the magnitude and quality of the immune response. Click here for more information about our Phase I/II trials.

Phase III On June 23, 1998, AIDSVAX was administered to the first volunteer in the world’s first Phase III trial for a preventive HIV/AIDS vaccine. Today, nearly 8,000 participants are enrolled in two separate VaxGen studies taking place on three continents. No other Phase III trials for preventive HIV vaccine have started, and we believe our nearest competitor is at least four years away from reaching a similar stage of development.

The first VaxGen trial is taking place among 5,400 participants in North America and the Netherlands. The bivalent vaccine used for the trial is designed to protect against two strains of HIV subtype B that predominate in North America, Western Europe, Australia, New Zealand and parts of South America. A second trial among 2,500 participants is taking place in Bangkok, Thailand, using a vaccine formulation designed to protect against the two predominant strains in Southeast Asia and the Pacific Rim. Click here for more information about our Phase III trials.

North America/Europe Thailand
Participants 5,400 2,500
Began Enrollment June 1998 March 1999
Completed Enrollment October 1999 August 2000
Clinics U.S., 54Canada, 3Puerto Rico, 1

Netherlands, 1

Bangkok, 17
Volunteers 5,100 gay men300 women 2,500 injectiondrug users
Trial Length 36 months 36 months
Endpoint Winter 2002 Summer 2003