ANNAPOLIS, Md., Sept. 24 /PRNewswire-FirstCall/ -- PharmAthene, Inc.
(Amex: PIP), a biodefense company developing medical countermeasures
against biological and chemical threats, announced today that the Company
is presenting two posters and an oral presentation on its medical
countermeasures programs, Protexia(R) (rBChE) and Valortim(R) at the HHS
Public Health Emergency Medical Countermeasures Enterprise (PHEMCE)
Stakeholders Workshop 2008 / BARDA Industry Day being held in Alexandria,
VA, September 24 - 26, 2008.
David P. Wright, President and Chief Executive Officer of PharmAthene
commented, "We want to commend BARDA's new leadership for moving forward
aggressively to engage with industry as a partner, and for their commitment
to providing greater transparency and a long-term strategy for biodefense
medical countermeasures research, development and procurement."
"We are delighted to have the opportunity to present these data at the
PHEMCE conference, which is an important industry meeting for companies in
the biodefense sector. As the data illustrate, PharmAthene continues to
advance its pipeline and further its leadership position in biodefense by
working collaboratively with the U.S. government to develop unique animal
models that can potentially accelerate product commercialization," Mr.
Wright continued.
Protexia(R), a recombinant version of human butyrylcholinesterase
(BChE), is being developed as a pre- and post-exposure therapy for
casualties on the battlefield or civilian victims of nerve agent attacks.
Valortim(R), in co-development with Medarex, Inc., (Nasdaq: MEDX) is a
fully human monoclonal antibody designed to treat and protect against
inhalational anthrax. Highlights of the poster presentations include:
-- A study of non-pegylated recombinant BChE in a guinea pig model
provides new data that suggests that the pegylated rBChE (Protexia(R)) may
have efficacy as a therapeutic against nerve agent exposure.
-- A study of Valortim(R) in a primate animal model utilizing the
African green monkey (AGM) shows promise as a potential therapeutic for the
treatment of inhalational anthrax.
-- A summary of the Valortim(R) development program, including
previously reported Phase I data demonstrating that Valortim(R) is safe and
well-tolerated, with no drug-related Grade 2-4 or serious adverse events
supporting the potential of Valortim(R) as a promising therapy for
treatment and post-exposure prophylaxis for inhalational anthrax.
Summary of Data Presented:
Non-pegylated rBChE Findings Reported
In a poster entitled, "Recombinant Butyrylcholinesterase (rBChE)
Therapy Following VX Poisoning by the Percutaneous Route: Preliminary
Results from Guinea Pig Studies," investigators studied the effects of
non-pegylated rBChE administered following poisoning by VX in an animal
model which mimics percutaneous exposure. In this model, free agent was
measured in both the dermis and blood enabling investigation of their
temporal relationships. Non-pegylated rBChE significantly reduced the
concentration of free VX in the blood. At 7.5 hours the cholinesterase
activity of the plasma was approximately 27 fold greater than control.
Additionally, brain cholinesterase levels were similar to previously
published data from untreated controls suggesting that non-pegylated rBChE
prevented the inhibition of these tissues by VX. The reduced concentration
of circulating free VX following poisoning by the percutaneous route in
animals treated with non-pegylated rBChE supports the conclusions of an
earlier study (Mikler et al, 2007) that rBChE has potential utility as a
post poisoning therapy. The investigators suggest that the data provide the
first tangible evidence of the predicted mechanisms of post poisoning
intervention with rBChE.
"The majority of our research to date for Protexia(R) has focused on
studying its efficacy as a pre-exposure prophylactic. The promising
preliminary data are particularly encouraging as they demonstrate that the
non-pegylated rBChE may also be efficacious as a therapeutic for nerve
agents. We plan to undertake further confirmatory work with Protexia(R) to
build upon these exciting preliminary observations," said Mr. Wright.
Valortim(R) Findings Reported
In a poster entitled, "Efficacy of Intravenous Valortim(R), an
Anti-toxin Monoclonal Antibody, in the Treatment of Inhalation Anthrax in
the African Green Monkey Model," investigators at USAMRIID sought to refine
the AGM as a therapeutic model by assessing the efficacy of an anti-toxin
monoclonal antibody. In the study, 21 adult AGMs were exposed by aerosol to
Ames anthrax spores and blood samples were collected every 4-8 hours
beginning 24-hours post exposure to assess anthrax bacteremia and
protective antigen in blood. Samples were analyzed for protective antigen
via a rapid electrochemiluminescent immunoassay (ECL) and bacteremia was
evaluated by 24-hour culture. In the study, 6 AGMs were treated with one
intravenous dose of 10 mg/kg Valortim(R) when positive by ECL; a second
cohort of 6 AGMs was treated with 2 intravenous doses of 10 mg/kg
Valortim(R) (the first given when positive by ECL and the second dose
administered 24 hours later), and a third cohort of 6 AGMs was treated with
one intravenous dose of 20 mg/kg Valortim(R) when positive by ECL.
Results showed that 56% (10 of 18) of the Valortim(R)-treated animals
survived while all saline-treated controls (3) succumbed to inhalational
anthrax on or before the fifth day post-exposure. Extended time-to-death
(days 6-9) was observed in 5 of the 8 Valortim(R)-treated animals that
succumbed to inhalational anthrax.
An oral presentation entitled, "Valortim(R), an Anti-toxin Monoclonal
Antibody, for the Treatment and Post-exposure Prophylaxis of Inhalation
Anthrax," provided a summary of the Valortim(R) development program.
In the Phase I clinical study, 46 human volunteers were administered
either a single dose of intravenous (IV) Valortim(R) (dose range 0.3
mg/kg-20 mg/kg) or intramuscular Valortim(R) (100mg). Valortim(R) was found
to be safe and well-tolerated with no drug-related Grade 2-4 or serious
adverse events reported. PK analysis demonstrated a half-life of
approximately 26 days for IV administration.
Valortim(R) has been tested in both the New Zealand White (NZW) rabbit
and non human primate models to evaluate its efficacy in the post-exposure
prophylaxis and therapeutic settings.
In the post-exposure setting, Valortim(R) was dosed starting one hour
after spore exposure. Valortim(R) protected >85% of both NZW rabbits and
non human primates at doses as low as 1 mg/kg beginning one hour after
exposure to spores.
In the therapeutic setting, Valortim(R) was dosed starting at fixed
time points after spore exposure (24 or 48 hours in the NZW rabbit) or
after first demonstrating antigenemia by a positive ECL assay (AGM).
Valortim(R) protected 88% and 42% of NZW rabbits that initiated treatment
at 24 and 48 hours after spore exposure, respectively. When AGMs were
treated with Valortim(R) at the time of first positive ECL after spore
exposure, 56% of the animals survived.
"We are very excited about the animal model data from the AGM study,
which showed over 50% of Valortim(R)-treated animals survived inhalational
anthrax as compared to no controls. This is especially compelling given
that the toxin-releasing bacteria were present in the bloodstream at the
time treatment was initiated. The AGM model, which we have been developing
with the United States Army Medical Research Institute of Infectious
Diseases (USAMRIID) is believed to closely mimic the disease course of
inhalational anthrax infection in humans. In this therapeutic model,
treatment with Valortim(R) is begun only after anthrax toxin is first
detected in the circulation. This model may provide an important
improvement over existing therapeutic models for anthrax by precisely
defining a standardized timing for therapeutic intervention," commented Mr.
Wright.
About Valortim(R)
Valortim(R) is a fully human antibody designed to protect against
inhalation anthrax, the most lethal form of illness in humans caused by the
Bacillus anthracis bacterium. The investigational antibody is designed to
target a protein component known as the anthrax protective antigen of the
lethal toxin complex produced by the bacterium. The anthrax protective
antigen is believed to initiate the onset of the illness by attaching to
cells in the infected person, and then is believed to facilitate the entry
of additional destructive toxins into the cells. Valortim(R) is designed to
target anthrax protective antigen and protect the cells from damage by the
anthrax toxins.
About Protexia(R)
Protexia(R) is a recombinant version of human butyrylcholinesterase
(BChE), a naturally occurring protein found in minute quantities in blood
(2 mg/liter). BChE functions as a natural bioscavenger, like a sponge, to
absorb and degrade organophosphate poisons (e.g. nerve agents) before they
cause neurological damage. Protexia(R) is being developed as a pre- and
post-exposure therapy for casualties on the battlefield or civilian victims
of nerve agent attacks. Nerve agents belong to a class of compounds known
as organophosphate (OP) agents. OP nerve agents, such as sarin gas, soman,
tabun or VX, enter the blood stream via inhalation or absorption through
the skin. The nerve agents travel in the circulatory system to the brain
and muscles causing the nerves to become over-stimulated which leads to
massive convulsions and death in severe cases.
About PharmAthene, Inc.
PharmAthene was formed to meet the critical needs of the United States
and its allies by developing and commercializing medical countermeasures
against biological and chemical weapons. PharmAthene's lead product
development programs include:
-- SparVax(TM) -- a second generation recombinant protective antigen (rPA)
anthrax vaccine
-- Third generation rPA anthrax vaccine
-- Valortim(R) -- a fully human monoclonal antibody for the prevention and
treatment of anthrax infection
-- Protexia(R) -- a novel bioscavenger for the prevention and treatment of
morbidity and mortality associated with exposure to chemical nerve
agents
-- RypVax(TM) -- a recombinant dual antigen vaccine for plague
For more information about PharmAthene, please visit
http://www.PharmAthene.com.
Statement on Cautionary Factors
Except for the historical information presented herein, matters
discussed may constitute forward-looking statements within the meaning of
the Private Securities Litigation Reform Act of 1995 that are subject to
certain risks and uncertainties that could cause actual results to differ
materially from any future results, performance or achievements expressed
or implied by such statements. Statements that are not historical facts,
including statements preceded by, followed by, or that include the words
"potential"; "believe"; "anticipate"; "intend"; "plan"; "expect";
"estimate"; "could"; "may"; "should"; or similar statements are
forward-looking statements. PharmAthene disclaims, however, any intent or
obligation to update these forward-looking statements. Risks and
uncertainties include risk associated with the reliability of the results
of the studies relating to human safety and possible adverse effects
resulting from the administration of the Company's product candidates,
unexpected funding delays and/or reductions or elimination of U.S.
government funding for one or more of the Company's development programs,
the award of government contracts to our competitors, unforeseen safety
issues, unexpected determinations that these product candidates prove not
to be effective and/or capable of being marketed as products, as well as
risks detailed from time to time in PharmAthene's Form 10-K under the
caption "Risk Factors" and in its other reports filed with the U.S.
Securities and Exchange Commission (the "SEC"). In particular, the studies
described above involving Protexia(R) and Valortim(R) constitute
non-clinical animal studies. Significant additional non-clinical animal
studies, human clinical trials, and manufacturing development work remain
to be done under both programs. At this point there can be no assurance
that either of these product candidates will be shown to be safe and
effective and approved by regulatory authorities for use in humans. Copies
of PharmAthene's public disclosure filings are available from its investor
relations department and our website under the investor relations tab at
http://www.pharmathene.com.
SOURCE PharmAthene, Inc.
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Related links:
http://www.PharmAthene.com
CONTACT:
Stacey Jurchison of PharmAthene, Inc.,
+1-410-269-2610, JurichsonS@PharmAthene.com
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