The Food and Drug
Administration has approved the Emory Vaccine Center’s application
to begin a Phase I clinical trial of its multiprotein AIDS vaccine.
Pending final approval of the trial by institutional review boards,
30 human volunteers at three sites around the country will begin
receiving the vaccine within the next several months.
Emory’s AIDS vaccine consists of two components: a DNA prime
and a recombinant poxvirus as a booster. The vaccine is designed
to promote a memory immune response against the three major proteins
(Gag, Pol, Env) expressed by HIV.
The first clinical trial will assess the safety of the vaccine’s
DNA priming component using three groups of volunteers at the University
of Alabama-Birmingham, the University of California at San Francisco
and the University of Washington in Seattle. The trial will compare
the effects of high and low dosages of the vaccine in two groups
of (HIV negative) volunteers, who will receive two intramuscular
injections. The third group will receive two injections of a placebo.
Preliminary results from the Phase I trial of the DNA component
of the vaccine should be available by the middle of next year. A
separate Phase I clinical trial of the booster is expected to begin
within a year and will involve different sets of volunteers.
“Most likely we will have to have a third trial to test the
combined regimen of the DNA and booster portions of the vaccine,”
said Harriet Robinson, chief of the Yerkes Division of Microbiology
and Immunology, who led the development of the vaccine.
Robinson is confident that the clinical trials will confirm the
vaccine’s ability to promote long-term protection against
HIV. In tests in 24 rhesus monkeys at Yerkes, the vaccine successfully
contained a highly virulent hybrid of simian and human immunodeficiency
Since the vaccinated monkeys were exposed to SHIV two years ago,
protective immunity against the virus has continued to improve.
According to a Yerkes study reported in the October 2002 edition
of the Journal of Virology, levels of viral DNA in the monkeys have
declined to the nearly undetectable levels characteristic of a small
subset of HIV-infected people, termed long-term nonprogressors,
who carry HIV but do not develop AIDS.
A California biotech company, ViCal, manufactured the priming components
of the AIDS vaccine for the Phase I clinical trial from the DNA
of clade B, the most common HIV subtype in North America and Western
Europe. Stanford Research Institute, another contract company, and
Yerkes have tested the vaccine’s safety in rabbits and rhesus
In late 2003, a Phase I clinical trial of a vaccine against clade
AG, the most common HIV subtype found in West Africa, will be launched
in the United States and then in Côte d’Ivoire (formerly
the Ivory Coast). The Emory Vaccine Center’s Hope Clinic will
serve as one of the clinical test sites for this trial.
Production of the vaccine against subtype AG will be overseen by
GeoVax Inc., the startup company founded by Emory and the Vaccine
Center for manufacture of the vaccine.
By late 2004, the Vaccine Center hopes to begin a Phase I trial
of a trivalent vaccine incorporating the DNA from clades B, AG,
and C. Subtype C is the most prevalent form of HIV in India and
Robinson projects that Phase III efficacy trials of the AIDS vaccine
could begin in 2006. Unlike the much smaller Phase I and II clinical
trials, several thousand volunteers will be recruited for the Phase
The HIV Vaccine Trials Network of the National Institute of Allergy
and Infectious Diseases will fund the initial Phase I trials.