Stressgen presents data at vaccine conference on next CoVal(TM) fusion in pipeline targeting HBV
Novel Therapeutic Vaccine HspBcor Activates Antigen-Specific Cellular
Immunity Against Hepatitis B
ARLINGTON, VA, May 6 /CNW/ - Stressgen Biotechnologies Corporation (TSX:
SSB) today presented its latest preclinical research results at the 6th Annual
Conference on Vaccine Research on its new CoVal(TM) fusion compound, HspBcor,
designed to treat chronic hepatitis B virus (HBV) infection. The presentation
included the results of studies performed by Stressgen scientists and Utah
State University under a collaborative agreement with the National Institute
of Allergy and Infectious Disease of the National Institutes of Health.
The results from the preclinical studies demonstrate that mice immunized
with the HspBcor fusion protein activate cellular immunity by generating
cytotoxic T lymphocytes (CTLs), peptide-specific white blood cells that can
recognize and kill infected cells expressing the HBV core antigen. This CTL
activity was triggered in normal mice, in mice that have been genetically
modified to contain components of a human immune system, and also in HBV
transgenic mice that express the entire HBV genome.
"In individuals with chronic HBV infection, viral persistence may be
related to an insufficient HBV-specific killer T cell (CTL) response,"
commented John D. Morrey, Ph.D., Professor at the Institute for Antiviral
Research at Utah State University. "In a subset of HBV transgenic animals,
Stressgen's HspBcor fusion protein appears to induce HBV core-specific killer
T cells. This result indicates a breaking of immune tolerance to an HBV
antigen, perhaps one of the major hurdles to an effective therapeutic vaccine
for HBV."
HBV transgenic mice are commonly employed as a model of chronic HBV
infection. Transgenic mice that are immunologically tolerant to HBV normally
do not rid themselves of cells expressing viral antigens, which makes them
comparable to humans suffering from chronic HBV infection. Nevertheless, a
single injection of HspBcor was observed to break immune tolerance to the HBV
core antigen in some of these transgenic mice by eliciting a specific CTL
response, an unusual phenomenon in such animals.
"We have previously seen similar preclinical results with HspE7, our
CoVal(TM) fusion that has shown activity in multiple phase II clinical trials
for diseases caused by human papillomavirus," said Marvin I. Siegel, Ph.D.,
Executive Vice President of Research and Development at Stressgen. "We are
hopeful that these preclinical data will be predictive of HspBcor's activity
as an immunotherapeutic for patients with chronic HBV infection."
About Hepatitis B:
Hepatitis B is the most common serious liver infection in the world. It
is caused by the hepatitis B virus that infects liver cells and can lead to
liver failure, cirrhosis or cancer of the liver. Despite the availability of a
safe and effective preventative vaccine, there are still more than 350 million
people worldwide chronically infected with the virus, according to the World
Health Organization. Without intervention, each year as many as one million of
these individuals will die from HBV-induced disease such as cirrhosis and
cancer. According to the CDC, more than 1.25 million Americans are chronically
infected with HBV, with 78,000 new infections reported in 2001.
According to the Hepatitis B Foundation, HBV is 100 times more infectious
than the AIDS virus. For the 350 million people worldwide who are already
chronic carriers of HBV, the existing preventative vaccine, as currently used,
is of no therapeutic value.
About Stressgen Biotechnologies Corporation:
Stressgen, a biopharmaceutical company, focuses on the discovery,
development and commercialization of innovative CoVal(TM) fusion
immunotherapeutics. The Company is developing a broad range of products for
the treatment of infectious diseases and cancer. Stressgen has programs to
evaluate its CoVal(TM) fusions in the treatment of diseases caused by human
papillomavirus, hepatitis B, hepatitis C and herpes simplex viruses. Stressgen
is also an internationally recognized supplier of research products used by
scientists worldwide for the study of cellular stress, apoptosis, oxidative
stress and neurobiology.
The Company is publicly traded on the TSX Toronto Stock Exchange under
the symbol SSB.
About CoVal(TM) Fusion Proteins
Stressgen capitalizes upon the immunostimulatory powers of heat shock
proteins (Hsp) utilizing recombinant technology to fuse, or covalently link, a
heat shock protein to disease-associated protein antigens. For more
information about our CoVal(TM) fusion proteins, or Stressgen, please visit us
at our website located at www.stressgen.com. |
