Aids vaccines still elusive, but human trials start
A San Francisco gay man, Ronald Walent, is a human guinea pic testing experimental vaccines and results are expected soonNational Institute of Allergy and Infectious Disease
October 6, 2003
SAN FRANCISCO — The patient's inoculation was as routine as any Dr. Robert
Johnston had seen. Roll up the sleeve, a cotton swab of alcohol on
the upper arm and a "this shouldn't hurt much."
What was in the syringe, though, was anything but typical: a
genetically engineered Venezuela equine encephalitis bug laden with
pieces of HIV, the virus that causes AIDS.
As nasty as that shot sounds, the biotechnology brew injected
into the volunteer's body that July day was not infectious - it was
designed to save lives. In fact, Johnston's research at the
University of North Carolina is just one of the latest AIDS vaccine
experiments that are moving from the laboratory to human tests.
An increasing number of human experiments, spurred by
biotechnology breakthroughs, has added a new word - optimism - to a
research field noted more for its failures than its successes over
the last two decades.
"I'm certainly more optimistic than just a couple of years ago,"
said Dr. Robert Gallo, who 20 years ago co-discovered the virus
that causes AIDS. "We can see the light at the end of tunnel."
Gallo, who heads the Institute for Human Virology at the
University of Maryland, expects to begin testing his own
experimental vaccine on humans soon.
Most AIDS researchers agree that vaccines will be the only
effective way to control a pandemic that has killed 28 million
people and infected 42 million more, most of them in Africa.
Unfortunately, most also agree that things will get worse before
they get better. Some five million people were infected last year
and another 3.1 million died.
"I tend to stay away from the word `optimism,"' said Dr. Anthony
Fauci, director of the National Institute of Allergy and Infectious
Disease. "I see things happening that make me feel better about the
process. But I don't want to give an impression that this is a new
dawn in America. We still have a long way to go."
AIDS is notoriously wily in beating the body's immune system and
so far has survived every drug thrown at it. In February, VaxGen
Inc. reported that the world's most advanced human vaccine
experiment - involving 5,000 volunteers - had flopped.
Nonetheless, a gathering two weeks ago in New York at the AIDS
Vaccine conference was palpably more upbeat and better attended
than years past, attendees said.
"There's cause for optimism," said Dr. Laurence Peiperl, an AIDS
researcher at the University of California, San Francisco. "There
are more interesting products going into clinical trials."
About two dozen potential vaccines are being tested by 12,000
human volunteers in experiments around the world. Several more
human experiments are about to start.
Fauci's federal institute has budgeted $456 million for HIV
vaccine research in fiscal 2004 - up from $413.6 million in 2003
and $182 million in 1999. Last month, it awarded $81 million in
contracts to four biotechnology companies for vaccine development.
"A safe and effective HIV vaccine is critical to the control of
HIV globally," Fauci said.
At least a dozen drug companies, including Merck & Co., the
world's largest, are developing AIDS vaccines. The projects range
from the commonplace to the exotic, like Large Scale Biology
Corp.'s attempt to grow a vaccine in genetically engineered tobacco
Most of these projects take one of two basic approaches.
One research approach is aimed at provoking the body's immune
system to make disease-fighting proteins called antibodies that
will forever fight off AIDS infections.
The other approach is designed to train specialized cells, known
as cytotoxic T lymphocytes and dubbed killer T-cells, to identify
and eliminate infected cells after someone contracts HIV.
The antibody defense is most desirable but the T-cell work has
shown more promising results. The vaccine Johnston helped created
employs both approaches.
The volunteers in vaccine experiments have not been infected
with the AIDS virus when they begin the trials but some are
considered at high risk of infection. Researchers judge the
vaccine's effectiveness by comparing the number of their subjects
who get HIV against an expected infection rate.
Nearly all vaccine researchers are attempting to provoke immune
responses in two ways: by engineering other viruses with bits of
HIV or injecting key bits of HIV's genetic material directly.
Ronald Walent of San Francisco has tried both types of
experimental vaccines. He volunteered for an experiment three years
ago that tested how two vaccines taken in combination would work.
Results are expected soon.
In August, the experiment was "unblinded" and participants were
told whether they received the combination or placebo. Walent got
"It's like getting a regular inoculation," said Walent, whose
partner died of AIDS. "But initially you do wonder what this stuff
is going to do you."
AIDS researchers said Walent, and all other human volunteers,
need not worry about contracting AIDS from the experimental
vaccines. Because HIV is so unpredictable, vaccine researchers
don't use the live virus in human experiments.
Walent said he practices safe sex and has little fear of getting
infected. Instead, the 54-year-old registered nurse was motivated
on several different levels to act as human guinea pig.
"It isn't just my little gay community that's affected, but huge
parts of Africa and Asia," he said. "You get older and a light bulb
finally goes off: Now is the time to make a difference." –Sapa-AP
University of North Carolina
Institute of Human Virology