DENVERA combination of two investigational HIV vaccines has
produced anti-HIV immune responses in more than 90% of volunteers at
least 1 year after vaccination, Robert Belshe, MD, of St. Louis
University, said at the International Society for Sexually
Transmitted Diseases Research meeting. These preliminary data
indicate both vaccines are safe, and side effects associated with the
injections are generally mild, Dr. Belshe said.
The phase II trial, known as AVEG 202/HIVNET 014, is being carried
out at 14 sites nationwide by two networks sponsored by the National
Institute of Allergy and Infectious Diseases (NIAID)the AIDS
Vaccine Evaluation Group (AVEG) and the HIV Prevention Trials Network
The two vaccines being used in the trial are vCP205 (Pasteur Merieux
Connaught, Lyon, France) and SF-2 rgp120 (Chiron, Emeryville,
California) (see box below)
About the Vaccines
The two vaccines used in the AVEG trial show promise for activating
The vCP205 vaccine consists of an attenuated canarypox virus
SF-2 rgp120 is a genetically engineered copy of the HIV surface
Since the vaccines contain only selected HIV genes or proteins, and
435 Volunteers Enrolled
The trial enrolled 435 healthy men and women not infected with HIV.
More than 80% of the participants had a recent history of intravenous
drug use or high-risk sexual behavior. All participants received
extensive and repeated counseling on reducing high-risk behaviors.
Enrollment began in May 1997, and the volunteers were randomly
assigned to one of three arms. One group received both vaccines; a
second group got vCP205 and a placebo; the third group received two
placebos. Volunteers received four doses, by injection, spread out
over 6 months.
All immunizations were completed by July 1998. One year later, more
than 90% of the volunteers in the two-vaccine arm and more than 50%
of those receiving vCP205 had developed antibodies that can inhibit
HIV in a laboratory assay, Dr. Belshe said.
So far, 11 volunteers have become infected with HIV, all as the
result of high-risk behaviorsix in the placebo group, three in
the single-vaccine arm, and two in the group receiving the
combination of vaccines. However, the trial is not designed to test
whether the vaccine combination can protect against HIV infection or
AIDS, Dr. Belshe said. Participants in the trial will continue to be
followed for a further 3 years.
Additional NIAID-sponsored studies are gathering more data on this
vaccination strategy before a large-scale efficacy trial is
considered. For example, two newer canarypox HIV vaccines are
undergoing a head-to-head evaluation. At this time, the data needed
to consider moving into the next phase of testing are expected to be
available by late 2000.