Volunteers start
receiving therapeutic HIV vaccine

Researchers at four participating universities are signing up volunteers to take part in an experimental HIV vaccine trial during its initial phase. St. Louis University, Vanderbilt University, the University of Maryland, and the University of Alabama at Birmingham will enroll 12 participants in the Phase I trial, in which uninfected, healthy volunteers are given low doses to check the vaccine's safety and participants' immune response, said Don Hildebrand, CEO of GeoVax, an Atlanta-based biotechnology firm that licensed the vaccine.

A Phase II trial, involving 36 people given a higher dose, is expected to start in a few months. Should these trials prove successful, said Hildebrand, future trials will be conducted to determine if the vaccine prevents HIV from progressing to an AIDS diagnosis.

The GeoVax vaccine was developed by a team led by Harriet Robinson of Emory University's Yerkes National Primate Research Center. Work on the vaccine began in 1997. It proved effective in rhesus macaques, protecting 22 of 23 vaccinated monkeys from AIDS for more than 3.5 years.

The vaccine is given in four doses over the course of approximately two months. The first two doses include fragments of HIV DNA that prime the volunteer's immune response system. The following doses contain an altered poxvirus designed to boost the immune system, said Hildebrand.

In 2003 and 2004, the DNA component of the GeoVax vaccine was tested in 30 HIV-negative participants in Birmingham, Ala., San Francisco, and Seattle, and it proved safe, Hildebrand said. The new trials are testing both components, he explained.

According to the International AIDS Vaccine Initiative, the GeoVax product is one of more than 30 HIV vaccines currently in early stages of human clinical trials in about two dozen countries. Merck's vaccine, which builds immunity using a modified cold virus, is one of the furthest along. Some 3,000 people are being enrolled in Phase II trials of the Merck vaccine. (AP)