The results of an Immune Tolerance Network (ITN)
study, published in the October 5, 2006 issue of the New England
Journal of Medicine suggest that a six-week experimental allergy
treatment can relieve hay fever symptoms for at least two years. The
researchers believe that the six-injection immunotherapy regimen with a
novel DNA-based drug known as ‘AIC’ could offer a significant
improvement over traditional allergen immunotherapy, which can require
several years of weekly or bi-weekly injections.
The
placebo-controlled, double blinded study, begun in 2001, examined 25
ragweed allergic (hay fever) volunteers at Johns Hopkins Asthma &
Allergy Center in Baltimore, MD. Participants receiving a short, six
week regimen with AIC prior to the initial allergy season showed
substantially lower nasal hay fever symptoms, used less allergy
medication and had higher quality of life scores than those receiving a
placebo. Symptomatic improvements in AIC-treated patients were found to
be maintained during the next subsequent ragweed season, despite no
further treatment of these individuals.
Standard immunotherapy
is a long-established treatment with proven clinical benefits for a
number of allergic conditions, including hay fever. Patients receive
regular injections containing small amounts of the offending allergen –
ragweed pollen, in the case of hay fever - eventually making them less
sensitive to inhalation of the allergen. While proven effective and
long-lasting, patients require several years of weekly or monthly
injections and are often unable to complete the treatments. Standard
immunotherapy also carries the risk of a serious allergic reaction to
the injected allergen.
In the current study, no serious
adverse reactions due to AIC were observed. Side effects of the
treatment were generally mild and limited to temporary redness around
the injection site.
Peter Creticos, MD, Johns Hopkins researcher
and principal investigator of the trial believes that this study
represents an important advance in allergy therapy.
"Effectively,
we have shown that it may be possible to safely reduce the treatment
time for ragweed allergy from several years down to six weeks," said
Creticos. "And we’re not just treating the symptoms, we’re targeting
the fundamental defects in the immune system that cause allergy."
AIC
is a novel DNA-based drug developed by Dynavax Technologies Corporation
of Berkeley, CA. Short for "Amb a 1 immunostimulatory sequence
conjugate", AIC contains a short piece of DNA known as an
"immunostimulatory sequence" that can modify immune system reactions.
In AIC, this immunostimulatory DNA sequence is linked to a portion of
the molecule that causes ragweed allergy (known as 'Amb a1').
Allergies
are caused by an over-reaction of the immune system to an otherwise
harmless substance, such as tree and plant pollens. In allergic
individuals, antibodies known as IgE are responsible for mediating the
allergic response. In the current study, the researchers found that,
like standard immunotherapy, AIC blocks the seasonal rise in
ragweed-specific IgE in allergic individuals. They also discovered an
apparent reduction in IL-4, an immune system messenger that helps
immune cells known as basophils migrate to nasal tissues where they
cause inflammation. Together, the researchers believe these results
hint that AIC is successfully reprogramming the immune system to
tolerate the presence of allergen, without over-reacting.
"Re-establishing
immune tolerance to allergens really is the ultimate goal in allergy
research," said University of California, San Diego’s David Broide, MD,
co-author and senior ITN advisor. "Based upon these findings, we appear
to be taking a large step towards this goal."
This study was
conducted by the Immune Tolerance Network, and sponsored by the
National Institute for Allergy and Infectious Diseases (NIAID), an
institute of the National Institutes of Health.
Doctors Broide
and Creticos are now embarking upon a follow-up ITN/NIAID-sponsored
study to determine whether the benefits of AIC treatment extend to a
specific type of asthma. The "AIRIA Study" will examine the efficacy of
AIC in 140 individuals with fall seasonal asthma – asthma sufferers
whose condition worsens in the fall due to an underlying ragweed
allergy. The researchers are seeking volunteers to participate in the
multicenter study, which is being conducted at clinical centers in
Baltimore, MD, Cincinnati, OH, Columbus, OH and Hershey, PA. More
information can be found at www.seasonal-asthma.org or by calling toll-free, 1-888-909-4949.
