Killer T Cells Against the AIDS Virus Appear to be Activated By
Combination Treatment With REMUNE(TM) (Investigational HIV-1 Immunogen)
and Antiviral Drugs Data Reported at the 13th International AIDS
Conference
CARLSBAD, Calif., Jul 13, 2000 /PRNewswire via COMTEX/ -- The Immune Response
Corporation (Nasdaq: IMNR) announced today that preliminary interim clinical
results from an ongoing Phase II trial in Spain indicate that functionally
active cytotoxic T lymphocytes (CTL) or "killer" T cells appear to be stimulated
in HIV-positive individuals treated with the Company's investigational product
REMUNE(TM) (HIV-1 Immunogen) in combination with antiviral drug therapy (ART).
CTLs are white blood cells of the immune system that are capable of killing
cells infected with HIV.
Professor Eduardo Fernandez-Cruz, M.D., Ph.D., Head of the Division of Clinical
Immunology at University General Hospital "Gregorio Maranon" in Madrid and
Principal Investigator of the Phase II trial of REMUNE in Spain presented the
data in an oral presentation at the 13th International AIDS Conference in
Durban, South Africa.
Dr. Fernandez-Cruz commented, "We observed an increase of a specific subset of T
cells displaying cell-surface proteins that are characteristic of effector CTLs
in REMUNE-treated individuals. Importantly, this investigation has also shown
that those effector CTLs are functionally active, that is to say, they have the
capability to kill cells expressing HIV antigens." Dr. Fernandez-Cruz indicated
that the CTL analysis includes a total of 23 patients and confirms earlier
results indicating that REMUNE may enhance the population of memory CTLs (cells
that can become effector CTLs upon re-exposure to a particular pathogen) in
patients concurrently on antiviral drug therapy.
"In the patients tested thus far, we are observing CTL activity against HIV only
in patients treated with REMUNE and not in the patients treated with antiviral
drugs alone. These data lend support to the investigational use of REMUNE in
conjunction with antiviral drugs in order to rebuild the immune system against
HIV. Specifically, boosting the population of CTLs that can kill other cells
infected with HIV may enable REMUNE to have a positive impact on viral load,"
said Dr. Fernandez-Cruz.
In addition, Dr. Fernandez-Cruz presented evidence that the REMUNE-induced CTLs
were capable of attacking the Clade B strain of HIV. Whereas, REMUNE itself is
derived from Clade A/G, an African strain of HIV, the CTLs induced by
immunization with REMUNE were able to recognize and attack Clade B, the most
common HIV strain in the U.S. and Europe. The same cross-strain reactive ability
has also been observed for REMUNE-induced CD4 helper T cells in proliferation
tests against HIV.
"These results indicate that the immune responses induced by REMUNE are directed
at conserved regions of the virus, or those less likely to mutate," said Dr.
Fernandez-Cruz. "This is an important observation given that HIV's ability to
mutate has been a key obstacle to developing effective therapeutic vaccines
against HIV. The apparent ability of REMUNE to stimulate broad cross-reactive
immune responses that include CTLs to several different strains of the virus
suggests that REMUNE may potentially address the mutation issue and also serve
as a potential universal immunogen with utility in different regions of the
world where different subtypes of the virus prevail."
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. |
