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BRIAN
DEER: THE VAXGEN EXPERIMENT Page 5
South
of VaxGen's offices, the next freeway exit gives
access to its powerhouse: Genentech. This is the
world's front-runner in medical biotechnology, with
seven licensed products, from human growth hormones
to a clot-buster, Activase. Twenty years ago the
company was all dreams and venture capital; its few
staff snipping and splicing genes in a wasteland
where shipyards had died. Today, their ranks of Mercs
and BMWs surround 26 buildings in biology's Silicon
Valley.
Stopping
by from time to time are visitors from its master,
the druggernaut Hoffman-La Roche. With twin
headquarters in Basle and New Jersey, and sales last
year of SWf24.7bn (œ10.2bn), this
vitamins-to-Valium giant has the marketing muscle
should AidsVax come on stream. At its own labs, Roche
shuns the vaccine race, but with taxes pledged to
line-and-jab Africa and Asia executives doodle in
billions on the hope that Francis pulls it off.
When
I flew to San Francisco to quiz Francis for this
story, Berman was ecstatic, in jeans and a check
shirt, over a new $1.4m vaccine facility. The
experiment produces a torrent of clinic samples; each
volunteer gives blood on 17 visits, and each sample
is split for tests. Giant freezers were being
installed to store bar-coded specimens. There could
be 400,000 in all. There's also a $500,000
microbiology kit going in: DNA sequencers, PCR
machines, centrifuges and the like. Soon he would
direct 30 staff in 20 rooms. He was like a
seven-year-old on Christmas Day.
The
first thing that struck me was the push of the
spending, irrespective of scientific achievements.
Apart from all the investment so far, Genentech had a
10,000-litre fermenting tank, half full of New Jersey
strain vaccine. Nobody wanted that, worth $1m,
flushed away, much less the careers of its makers.
The next thing I noted was the standard of safety
imposed on the facility's construction. To handle a
dangerous pathogen in California, the
brown-and-yellow building, made from tipped-upright
concrete slabs, was stamped with certificates and
permits by the box load before the first plank was
sawn. It's both earthquake- and microbe-proof. And
its forests of copper pipes, air ducts and
bio-filters were tested to tolerances few structures
could endure.
But
while regulations make sure that the building is
safe, critics say that the product itself escapes
much rigorous scrutiny. With vaccines, any problems
often don't appear until mass-market use, and such is
the head of steam building up behind Francis that
sceptics think that if AidsVax doesn't join the
annals of useless shots, it has the potential to
join, say, a 1960s measles vaccine that made the
disease in those infected worse.
What
worries some scientists is that because AidsVax
provokes antibodies to its own specific gp120
strains, there's a risk that it may actually suppress
the immune system's ability to combat other strains.
On this thinking (the principle is sometimes called
"deceptive imprinting") even if the junkies
were protected against the New Jersey and Chiang Mai
strains, they might die more quickly if they get
infected with one of the countless other mutations.
"There's nothing new in this," Dr Heinz
Kohler, who has led investigations at Kentucky
University, said. "It's just common sense."
At
Kansas University, researchers have found that
monkeys injected with gp120 and then a hybrid kind of
HIV had more of the virus in their blood later on
than infected animals which weren't vaccinated.
"The question is: will those people who are
vaccinated progress to Aids more quickly if they
become infected with HIV than those who were not
vaccinated at all?" Prof McMichael at Oxford
summarised. "We might not know the answer for 10
years."
No
such problems were revealed in the preliminary tests,
but despite the importance of long-term follow-up
(recipients of the hepatitis B vaccine that Francis
worked on in the early 1980s have been tracked for
two decades), VaxGen no longer monitors what has
happened to the people who received its product in
the mid-1990s preliminary tests. Francis argues that
it makes more sense to wait for the full-scale trial
results.
This
apparent loss of data is surprising to some, because
history warns of the pitfalls of not being thorough.
In 1955, just one month after a near-hysterical press
conference in Michigan launched polio vaccine,
reports poured in to the CDC of hundreds of children
going down with the disease, induced by the shots
themselves. President Dwight Eisenhower said that,
because of the "great pressure to bring this
out", scientists may have "short-cut a
little bit".
AidsVax
cannot give volunteers Aids, but there may be
something even more terrifying than the anxiety that
it might accelerate their disease if they are later
infected with HIV. Some scientists think that, if it
works at all, the product may have a dangerous effect
on the evolution of HIV. Five years ago, Los Alamos
scientists declared that there was "no simple
answer" as to whether Aids could become
contagious through coughs and sneezes - and other
researchers argue that, in much the same way as a
partial course of antibiotics can promote resistant
bacteria, so a poorly-effective vaccine may promote
more deadly and infectious strains.
This
may sound like journalistic scare, but HIV's
best-understood RNA cousin is influenza virus, which
produces devastating mutations every 20 or 30 years.
Hepatitis B virus, meanwhile, has already produced
mutant strains accepted as being vaccine-induced.
"When you use a vaccine, you are introducing
another selective pressure," Dr Paul Ewald,
professor of biology at Amherst College,
Massachusetts, explained. "It could make the
problem more damaging, or less damaging, depending on
the antigen you use."
Researchers
told me that, compared with the potential risks to
volunteers, this doomsday scenario was
"unlikely". But with agencies standing by
to jab hundreds of millions of people, some wondered
if, for our species' safety, "unlikely" was
reassuring enough. "My personal view," Dr
Art Ammann, president of the San Francisco-based
Global Strategy for HIV Prevention, and a former
AidsVax researcher, said, "is that we could face
a global nightmare."
*****
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