Gene therapy shows promise as HIV treatment
5 March 2009
A study by the University of California Los Angeles (UCLA) AIDS
Institute has found that gene therapy can be developed as a safe and
active technique to combat HIV.
Researchers involved in this first-of-its-kind study found that
cell-delivered gene transfer has the potential to be a once-only
treatment that reduces viral load, preserves the immune system and
avoids lifelong antiretroviral therapy. The study has been published in
the online edition of the journal Nature Medicine.
Though modest, the results do show some promise that gene therapy can
be developed as a potentially effective treatment for HIV, said lead
investigator Dr Ronald Mitsuyasu, professor of medicine and director of
the Center for Clinical AIDS Research and Education (CARE) at the David
Geffen School of Medicine at UCLA.
"It is the first randomized controlled study done with gene therapy
in HIV," said Mitsuyasu, who is also an associate director of the UCLA
AIDS Institute. "What we were able to demonstrate was that the patients
who received the gene-modified cells had a somewhat better suppression
of their HIV viral replication after discontinuing their highly active
antiretroviral therapy (HAART) treatment, compared with the controls."
This was the first randomized, double-blind, placebo-controlled
gene-transfer clinical trial and involved 74 HIV-positive adults. The
patients received their own blood stem cells, either untreated or
modified to carry a molecule called OZ1, which prevents viral
replication by targeting a key HIV gene. OZ1 was safe, causing no
adverse effects over the course of the 100-week trial.
At the primary end-point, the difference in viral load between the
OZ1 and placebo group at weeks seven and eight, after they had stopped
HAART treatment, was not statistically significant. But other viral
parameters did demonstrate better HIV suppression and improvement in the
counts of CD4+ lymphocytes — the cell population that is depleted by
The technique still needs to be developed further and perfected,
Mitsuyasu said. "Part of the reason that we didn't see a larger effect
is that the persistence of the anti-HIV gene in the patient's blood was
not as long as we would have liked," he said. "We need to find better
ways to get the genes into the patients and maintain them, which could
include using different vectors to get the gene into the cells or
conditioning the patients prior to gene transfer."
Still, the results indicate that gene therapy could eventually be a
useful tool in the fight against AIDS, said study co-author Dr Thomas
Merigan, the George and Lucy Becker Professor of Medicine emeritus at
the Stanford University School of Medicine. He agrees that more needs to
be done to perfect it.
"But in the way we set up the trial with randomized placebo controls,
we could dissect out that there was a positive effect in patients who
had the gene successfully installed," Dr Merigan said. "This could be a
first step in developing a new method of controlling a chronic
This study was funded by Johnson and Johnson Research Pty Limited.
Grants from the National Institutes of Health also helped support part
of the research.
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