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PINE BROOK, N.J. -- Scientists from Elusys
Therapeutics, Inc. presented data today showing that the company's anthrax
antibody, ETI-204, provides complete protection from death due to anthrax
exposure in two animal species, and may clear anthrax bacteria from the site
of infection and from the bloodstream. The data were presented at the
American Society for Microbiology's Biodefense Research Meeting in Baltimore.
ETI-204, an affinity-enhanced monoclonal antibody (Mab), is being
developed as a drug for prevention and treatment of infection and death caused
by anthrax toxin.
"ETI-204 continues to deliver strong data demonstrating its protective
power at low doses," said Linda Nardone, PhD, vice president of clinical and
regulatory affairs for Elusys and director of the company's anthrax biodefense
program. "ETI-204 is one of the best anti-anthrax antibodies under
Leslie Casey, PhD, senior director of research at Elusys, presented the
results of two key studies at the meeting. One trial showed that mice given
ETI-204 fared significantly better than those given a non-affinity enhanced
Mab (14B7) or placebo. The mice received ETI-204, 14B7 or placebo followed by
injection of anthrax spores into the trachea. All of the mice given ETI-204
were still alive at the end of the 14-day trial. Even more significantly,
none of the mice given ETI-204 had evidence of anthrax bacteria spreading to
The second study found that the Elusys Mab completely protected rabbits
exposed to aerosolized anthrax. ETI-204 was given intravenously to the
animals in the study group immediately before exposure to a lethal dose of
aerosolized anthrax. The control group received no drug. All of the animals
given ETI-204 survived the 28-day study, whereas none of the rabbits in the
control group survived past five days.
Casey presented compelling new data based on blood samples drawn from
the rabbits to determine the level of anthrax bacteria in the blood and major
organs. These data go beyond the survival data for the rabbits that were
Seven of the nine rabbits treated with ETI-204 had no evidence of bacteria
in the lungs, which was the site of infection, and none of the treated rabbits
had bacteria in their blood at any time point. This was unexpected because
ETI-204 targets the anthrax toxin, not the bacteria, yet it seems to clear
bacteria from the site of infection and to keep it out of circulation in the
Also remarkable was that there was no evidence of ETI-204 in the
bloodstreams of the treated rabbits by day 28, yet the rabbits remained free
"Our pre-exposure studies show that a single low dose of ETI-204 before
exposure to lethal levels of anthrax protects the animals from death caused by
anthrax toxin, but does even more than that," commented Casey. "It was
unexpected, but striking, that our Mab prevented bacteria from entering the
bloodstream and cleared the bacteria from the site of infection. ETI-204
appears to have some very beneficial effects that we plan to study further."
Finally, blood samples from the rabbits indicated that the animals
developed their own antibodies to the anthrax toxin. "ETI-204 may also enable
recipients to mount their own immune response to anthrax. We may test this
further to verify the effectiveness and duration of this effect," added Casey.
"We have new data showing that ETI-204 protects animals when it is given
after they have been exposed to anthrax spores," added Nardone. "In
addition, we have excellent data that show protective levels of ETI-204 can be
deliver by intramuscular injection, which will allow more rapid deployment
than intravenous injection, especially in emergency situations." Elusys will
release the post-exposure and intramuscular data in the near future.
ETI-204 is an affinity-enhanced, de-immunized antibody, which means that
its ability to bind to its target pathogen has been strengthened and that
elements that might cause an immune response have been removed. ETI-204
targets and binds to Protective Antigen, which prevents the anthrax toxins
from binding to and entering the cells in the body, thereby preventing death.
Elusys develops antibody-based therapies using proprietary technology in
Heteropolymer antibody chemistry and complement biology. The company's
pipeline of products includes treatments for cancer, lupus nephritis,
infectious diseases and thrombosis. The company has successfully advanced
three products to the IND and Phase I stage, with additional products in its