All sites up and running on AIDS vaccine trials
AIDSVAX trials enroll 5,000 in North America
Three-year phase III trials are fully under way at about 50 sites in more than 25 states for one of the nation’s most promising AIDS vaccines under study.
AIDSVAX is a genetically engineered, aluminum-adjuvanted subunit investigational vaccine developed by VaxGen, a biotechnology company in San Francisco. The vaccine is made from a copy of a protein from the surface of HIV and contains no HIV DNA, so there’s no chance the vaccine could cause HIV infection.
AIDSVAX trials also have opened recently in Amsterdam and in Canada. "We plan to continue volunteer enrollment throughout the summer," says Nicole Lynch, VaxGen spokeswoman.
The randomized, double-blind, placebo-controlled trial will enroll 5,000 people between the ages of 18 and 60 who do not have HIV-1 infection but are at risk of acquiring it through sexual contact. The North American trial will not use injection drug users.
At least one trial site has had no trouble finding volunteers interested in the study. "We’ve been overloaded with more than 100 calls in the week after a television program featured the study," says Veronica Pettigrew, RN, research coordinator for the Community Medical Research Institute of Community Hospitals in Indianapolis. The Indiana site will enroll a minimum of 100 people.
Vaccine volunteers had no allergic reactions
Indiana trial participants, who first enrolled in March, have responded well medically to the vaccine, Pettigrew says.
"We haven’t had an allergic reaction," Pettigrew says. "The only side effects we’ve seen are the same effects a person will have with any shot in a muscle — no cellulitis and not a lot of fevers related to the drug."
The trial’s participation level also has been good, she adds. The site’s early participants readily showed up for their first two vaccination shots, which are given a month apart.
Two out of three AIDSVAX participants receive the vaccine, and the other group receives a placebo. Counselors advise volunteers to continue safe sex practices because they will not know whether they have received the vaccine or the placebo.
Volunteers receive seven shots over a three-year period, at these times: baseline, one month, six months, 12 months, 18 months, 24 months, and 30 months. Research coordinators draw blood and assess the participant’s tolerability to the vaccine every 14 days after each immunization. They’ll continue follow-up for six months after the last vaccination is administered, and volunteers will be tested for HIV infection at six-month intervals throughout the study period. Researchers will follow volunteers who become infected with HIV for 24 months at four-month intervals or until the study ends, whichever is longer.
New formulation covers many viral strains
Research on AIDSVAX began in 1984 by a research team at San Francisco-based Genentech Inc., which now is the manufacturing and development partner for the vaccine. The first-generation vaccine, while found to be safe and effective, did not cover all strains of HIV circulating in the population. Researchers then began researching a second-generation vaccine that contains additional gp120 protein and has a much broader representation of circulating HIV strains.
Clinical trials on the first-generation vaccine began in March 1992 in cooperation with the Washington, DC-based National Institutes of Health. Once the phase I trials showed the vaccine was safe for humans, researchers began phase II trials.
Then in 1995, two top vaccine researchers led a spin-off of the Genentech HIV vaccine effort and formed VaxGen to concentrate on its further development, eventually leading to the formulation of the AIDSVAX vaccine, which is designed to protect against the two major strains of HIV found in the Americas, Europe, and Asia. The Rockville, MD-based Food and Drug Administration approved the phase III trial in June 1998.
Pettigrew says she’s optimistic she’ll see the day when the AIDS vaccine is as readily available as the many other immunizations.
"I’m real excited because I’m pregnant right now, and I’m hoping that in a few years the AIDS vaccine will be like vaccines for mumps, rubella, measles, or hepatitis," she says. "I think of how this child of mine might be out there doing things I wouldn’t want him to do, and with the vaccine he’ll be protected."
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