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Interim Results in a Patient Subset Indicate That
Treatment
With
REMUNE(TM) and Antiviral Drugs May Stimulate `Killer` T Cell Activity
Clinical Trial Data from Phase 2 Spanish Trial Reported at the Fifth
European Conference on Experimental AIDS Research (ECEAR) 2000
CARLSBAD, Calif., June 21 /PRNewswire/ -- The Immune Response Corporation
(Nasdaq: IMNR) announced today preliminary interim clinical results which
indicate REMUNE(TM) (HIV-1 Immunogen) may stimulate cytotoxic T
lymphocytes (CTL) or "killer" T cell activity specifically against HIV, the AIDS virus,
in people infected with HIV concurrently on antiviral drug therapy (ART). These
data represent two-year immunological results from a Phase 2 clinical trial of
REMUNE, an investigational product, currently being tested in Spain (STIR-2102).
These data were presented on June 18 at the Fifth European Conference on
Experimental AIDS Research (ECEAR) 2000 in Madrid, Spain. CTLs are white
blood cells of the immune system (CD8 lymphocytes) capable of directly killing
virus-infected cells.
"These data suggest that treatment with REMUNE may enhance the immune
system`s reserves of HIV-specific CTLs. This is very significant because CTL
immune responses are typically lost, or decline to very low levels, in people
chronically infected with HIV despite successful control of viral replication with
antiviral drug therapy," said Professor Eduardo Fernandez-Cruz, M.D., Head of the
Division of Clinical Immunology at University General Hospital "Gregorio Maranon"
in Madrid and Principal Investigator of the Spain trial. "Because CTLs detect and
kill virus-infected cells, boosting the population of CTLs that specifically react to
HIV may enable REMUNE to have a favorable impact on viral load."
Data on the blood samples taken 24 months into the Phase 2 trial from
pre-selected sites were analyzed in such a way as to ensure that the trial remains
blinded. Immunological tests were performed to measure the effect of treatment
with REMUNE on CTL immune responses as well as CD4 "helper" T cells, which
are the specific targets of HIV infection.
Dr. Fernandez-Cruz reported that in the subset of patients tested for CTL activity
specific to HIV, all the patients tested receiving ART plus REMUNE showed
significant CTL activity specifically against the virus, while all the patients tested
receiving ART plus placebo showed little or no CTL activity in the same test. In
addition, a significant increase in the overall number of memory CD4 T cells and
memory CD8 T cells was observed in REMUNE versus placebo groups of the
subset. (Memory T cells are formed after exposure to a pathogen and increase the
immune system`s ability to mount a swift attack when challenged again with the
same pathogen.) The proliferation of CD4 T cells in response to HIV-1 antigens as
well as production of a soluble cytokine, interferon-gamma, which is a measure of
helper T-CD4 cell function, was significantly higher in the ART plus REMUNE
group (27 patients) compared to the ART plus placebo group (27 patients). The
interferon-gamma levels were also strongly correlated with levels of anti-HIV factors
secreted by CD8 T cells (such as the beta-chemokines, RANTES and MIP-1
beta).
"Helper T cell immune responses and activated CTL precursors appear to increase
in the patients with length of time of vaccination. These data provide evidence that
some constant level of exposure to HIV, as with a therapeutic vaccine, may be
necessary to induce the immune system to generate an immune response against
the virus," said Dr. Fernandez-Cruz. "Of particular note," he continued,
"REMUNE-treated individuals had helper T cell immune responses, which most
likely activated and expanded the CTLs which have the capability to kill infected
cells. We hope that such anti-HIV immune responses will translate into an
enhancement of viral suppression, which is important for long-term management of
HIV-1."
Background
CTLs or CD8 killer T cells are believed to play an important role in combating HIV
infection by at least three different mechanisms, which may not be mutually
exclusive. First, CTLs are capable of directly killing HIV-infected cells by releasing
cytotoxic molecules (e.g., perforin) that lyse, or punch holes, in those cells
causing them to die. Without the host`s cellular machinery, HIV cannot replicate.
Second, CTLs also release another set of factors that include beta chemokines
(e.g., RANTES, MIP-1 alpha, MIP-1 beta) that compete with HIV particles for
preferred entry sites on the surface of helper T cells, thereby thwarting the
hallmark viral invasion of the helper T cell population. Finally, CTLs also release
factors called cytokines that suppress the ability of the virus to replicate within an
already infected host cell.
The REMUNE (STIR-2102) study in Spain is a double blind placebo-controlled trial,
which enrolled 243 HIV-infected patients naive to antiviral drugs prior to time of
enrollment. The efficacy of REMUNE administered in combination with antiviral
drugs will be assessed by comparing the time to increases in viral load or
decrease in CD4 helper T cell counts between patient groups that received ART
plus REMUNE or ART plus placebo. The trial is being conducted at 13 clinical
centers throughout Spain.
The Immune Response Corporation is a biopharmaceutical company based in
Carlsbad, California, developing immune-based therapies to induce specific T cell
responses for the treatment of HIV, autoimmune diseases and cancer. In addition,
the Company is developing a targeted non-viral delivery technology for gene
therapy that is designed to enable the intravenous injection of genes for delivery to
the liver.
NOTE: News releases for The Immune Response Corporation are available through
PR Newswire Company News On-Call fax service. For a menu of available news
releases or to retrieve a specific release made by The Immune Response
Corporation, please call 800-758-5804, extension 434675. Please retain these
numbers for future reference. Company information can also be located on the
Internet Web Site: www.imnr.com. This news release contains
forward-looking statements. Actual results could vary materially from those
expected due to a variety of risk factors, including, but not limited to, whether
additional clinical trials will be successfully concluded and whether REMUNE will
be approved for marketing or be successfully commercialized. Those factors are
discussed more thoroughly in The Immune Response Corporation`s SEC filings,
including but not limited to its report on Form 10-K for the year ended December
31, 1999 and subsequent forms 10-Q. The Company undertakes no obligation to
publicly release the results of any revisions to these forward-looking statements
which may be made to reflect events or circumstances after the date hereof or to
reflect the occurrence of unanticipated events.
REMUNE (TM) is a trademark of The Immune Response Corporation.
SOURCE The Immune Response Corporation
Interim Results in a Patient Subset Indicate That
Treatment
With
REMUNE(TM) and Antiviral Drugs May Stimulate `Killer` T Cell Activity
Clinical Trial Data from Phase 2 Spanish Trial Reported at the Fifth
European Conference on Experimental AIDS Research (ECEAR) 2000
CARLSBAD, Calif., June 21 /PRNewswire/ -- The Immune Response Corporation
(Nasdaq: IMNR) announced today preliminary interim clinical results which
indicate REMUNE(TM) (HIV-1 Immunogen) may stimulate cytotoxic T
lymphocytes (CTL) or "killer" T cell activity specifically against HIV, the AIDS virus,
in people infected with HIV concurrently on antiviral drug therapy (ART). These
data represent two-year immunological results from a Phase 2 clinical trial of
REMUNE, an investigational product, currently being tested in Spain (STIR-2102).
These data were presented on June 18 at the Fifth European Conference on
Experimental AIDS Research (ECEAR) 2000 in Madrid, Spain. CTLs are white
blood cells of the immune system (CD8 lymphocytes) capable of directly killing
virus-infected cells.
"These data suggest that treatment with REMUNE may enhance the immune
system`s reserves of HIV-specific CTLs. This is very significant because CTL
immune responses are typically lost, or decline to very low levels, in people
chronically infected with HIV despite successful control of viral replication with
antiviral drug therapy," said Professor Eduardo Fernandez-Cruz, M.D., Head of the
Division of Clinical Immunology at University General Hospital "Gregorio Maranon"
in Madrid and Principal Investigator of the Spain trial. "Because CTLs detect and
kill virus-infected cells, boosting the population of CTLs that specifically react to
HIV may enable REMUNE to have a favorable impact on viral load."
Data on the blood samples taken 24 months into the Phase 2 trial from
pre-selected sites were analyzed in such a way as to ensure that the trial remains
blinded. Immunological tests were performed to measure the effect of treatment
with REMUNE on CTL immune responses as well as CD4 "helper" T cells, which
are the specific targets of HIV infection.
Dr. Fernandez-Cruz reported that in the subset of patients tested for CTL activity
specific to HIV, all the patients tested receiving ART plus REMUNE showed
significant CTL activity specifically against the virus, while all the patients tested
receiving ART plus placebo showed little or no CTL activity in the same test. In
addition, a significant increase in the overall number of memory CD4 T cells and
memory CD8 T cells was observed in REMUNE versus placebo groups of the
subset. (Memory T cells are formed after exposure to a pathogen and increase the
immune system`s ability to mount a swift attack when challenged again with the
same pathogen.) The proliferation of CD4 T cells in response to HIV-1 antigens as
well as production of a soluble cytokine, interferon-gamma, which is a measure of
helper T-CD4 cell function, was significantly higher in the ART plus REMUNE
group (27 patients) compared to the ART plus placebo group (27 patients). The
interferon-gamma levels were also strongly correlated with levels of anti-HIV factors
secreted by CD8 T cells (such as the beta-chemokines, RANTES and MIP-1
beta).
"Helper T cell immune responses and activated CTL precursors appear to increase
in the patients with length of time of vaccination. These data provide evidence that
some constant level of exposure to HIV, as with a therapeutic vaccine, may be
necessary to induce the immune system to generate an immune response against
the virus," said Dr. Fernandez-Cruz. "Of particular note," he continued,
"REMUNE-treated individuals had helper T cell immune responses, which most
likely activated and expanded the CTLs which have the capability to kill infected
cells. We hope that such anti-HIV immune responses will translate into an
enhancement of viral suppression, which is important for long-term management of
HIV-1."
Background
CTLs or CD8 killer T cells are believed to play an important role in combating HIV
infection by at least three different mechanisms, which may not be mutually
exclusive. First, CTLs are capable of directly killing HIV-infected cells by releasing
cytotoxic molecules (e.g., perforin) that lyse, or punch holes, in those cells
causing them to die. Without the host`s cellular machinery, HIV cannot replicate.
Second, CTLs also release another set of factors that include beta chemokines
(e.g., RANTES, MIP-1 alpha, MIP-1 beta) that compete with HIV particles for
preferred entry sites on the surface of helper T cells, thereby thwarting the
hallmark viral invasion of the helper T cell population. Finally, CTLs also release
factors called cytokines that suppress the ability of the virus to replicate within an
already infected host cell.
The REMUNE (STIR-2102) study in Spain is a double blind placebo-controlled trial,
which enrolled 243 HIV-infected patients naive to antiviral drugs prior to time of
enrollment. The efficacy of REMUNE administered in combination with antiviral
drugs will be assessed by comparing the time to increases in viral load or
decrease in CD4 helper T cell counts between patient groups that received ART
plus REMUNE or ART plus placebo. The trial is being conducted at 13 clinical
centers throughout Spain.
The Immune Response Corporation is a biopharmaceutical company based in
Carlsbad, California, developing immune-based therapies to induce specific T cell
responses for the treatment of HIV, autoimmune diseases and cancer. In addition,
the Company is developing a targeted non-viral delivery technology for gene
therapy that is designed to enable the intravenous injection of genes for delivery to
the liver.
NOTE: News releases for The Immune Response Corporation are available through
PR Newswire Company News On-Call fax service. For a menu of available news
releases or to retrieve a specific release made by The Immune Response
Corporation, please call 800-758-5804, extension 434675. Please retain these
numbers for future reference. Company information can also be located on the
Internet Web Site: www.imnr.com. This news release contains
forward-looking statements. Actual results could vary materially from those
expected due to a variety of risk factors, including, but not limited to, whether
additional clinical trials will be successfully concluded and whether REMUNE will
be approved for marketing or be successfully commercialized. Those factors are
discussed more thoroughly in The Immune Response Corporation`s SEC filings,
including but not limited to its report on Form 10-K for the year ended December
31, 1999 and subsequent forms 10-Q. The Company undertakes no obligation to
publicly release the results of any revisions to these forward-looking statements
which may be made to reflect events or circumstances after the date hereof or to
reflect the occurrence of unanticipated events.
REMUNE (TM) is a trademark of The Immune Response Corporation.
SOURCE The Immune Response Corporation
