ANNAPOLIS, Md. and PRINCETON, N.J., July 31 /PRNewswire-FirstCall/ --
PharmAthene, Inc., a biodefense company developing and commercializing
medical countermeasures against biological and chemical threats, and
Medarex, Inc. (Nasdaq: MEDX), a leading monoclonal antibody company, today
announced the results of new studies showing that the companies' anthrax
anti-toxin, Valortim(TM) may possess the ability to enhance macrophage
killing of Bacillus anthracis (anthrax) spores within macrophages,
potentially blocking the ability of these spores to develop into bacteria,
thereby preventing toxin production and propagation of the infection.
The new data were recently presented by Dr. Alan Cross, Professor of
Medicine, University of Maryland School of Medicine, Baltimore, Maryland,
and Dr. Solomon Langermann, Vice President and Chief Scientific Officer for
PharmAthene, at the Bacillus ACT 2007 International Conference on Bacillus
anthracis held June 17-21 in Oslo, Norway. Valortim, a fully human
monoclonal antibody generated by Medarex's UltiMAb(R) technology, is being
co-developed for potential use as an anti-toxin therapeutic to prevent and
treat inhalation anthrax.
The studies presented by Drs. Cross and Langermann explored the
mechanism by which Valortim promotes the killing of Bacillus anthracis
(anthrax) in vitro (in test tube).
"These new data show that Valortim may enhance macrophage killing of
anthrax spores, and suggest that Valortim might also be able to block
germinating spores from producing rapidly growing bacteria with release of
the lethal toxins which are usually fatal in infected individuals," said
Dr. Cross. "Another interpretation is that Valortim may neutralize the
deleterious effects of anthrax toxins in the immune system thereby allowing
the mouse innate immune system to deal more effectively with the
infection."
A preclinical study led by Dr. Cross showed that Valortim protected
mice from lethal infection with Bacillus anthracis. In the study, mice were
pretreated with 5-10 mcg of Valortim and then exposed to spores of the
Bacillus anthracis Sterne strain of anthrax via injection. Of the seven
mice pretreated with Valortim, all survived compared to seven mice in a
control group, in which none received Valortim and none survived. These
data extend the panel of animals in which the in vivo protective activity
of Valortim against anthrax infection has been demonstrated, and offers an
attractive mouse model for further studies.
In a second study, Valortim was applied in vitro to mouse macrophages
and Bacillus anthracis spores. The results showed that the addition of
Valortim enhanced the killing of Bacillus anthracis (anthrax) spores by
macrophages in a time and dose-dependent manner.
"We have assumed that the potent anthrax toxin neutralizing activity of
Valortim protects infected organisms from overwhelming toxin production
made by replicating bacteria," remarked Dr. Langermann. "However, Dr.
Cross' research suggests that activity of Valortim may also be manifested
at an earlier stage, by enhancing the initial spore killing activity of
macrophages, which are specialized immune system cells. Further work is
ongoing to more fully characterize these intriguing results."
"The presence of the exosporium (a coating of bacterial derived
components that normally surround free spores) has been shown by Dr. Cross
in previous research to inhibit killing of spores by macrophages,"
commented Dr. Israel Lowy, Senior Director of Clinical Science and
Infectious Diseases at Medarex. "The experiments suggest that Valortim
might negate inhibitory effects of the exosporium, and allow the macrophage
to regain its full sporicidal activity. We look forward to further studies
of this potential mechanism of Valortim in impeding anthrax infection."
The work reported by Dr. Cross is supported by the Maryland Industrial
Partnerships Program (MIPS). The MIPS program was developed to accelerate
the commercialization of technology in Maryland by jointly funding
collaborative R&D projects between companies and University System of
Maryland faculty.
About Valortim
Valortim (MDX-1303) is a fully human antibody designed to protect
against anthrax infection, including 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 (PA) 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 is designed to target anthrax protective antigen and
protect the cells from damage by the anthrax toxins.
Valortim has been administered intravenously and intramuscularly to
healthy human volunteers in a completed phase I study, and was well
tolerated at doses as high as 20 mg/kg (IV), and was not immunogenic. These
study results were presented at the 2006 Annual Meeting of the Infectious
Diseases Society of America. Pharmacokinetic analysis suggested that doses
as low as 1 mg/kg resulted in circulating levels of antibody after a month,
with a similar potency for neutralizing anthrax toxin in vitro as was seen
with serum obtained from subjects who had been vaccinated with anthrax
vaccine.
Preclinical studies suggest that Valortim has the potential to provide
protection against anthrax infection when administered prophylactically
(prior to the emergence of symptoms of anthrax infection) and also may
increase survival when administered therapeutically (once symptoms become
evident).
About Anthrax
According to the Centers for Disease Control and Prevention, anthrax is
an acute infectious disease caused by the spore-forming bacterium Bacillus
anthracis. Anthrax most commonly occurs in hoofed mammals and can also
infect humans. Symptoms of disease vary depending on how the disease is
contracted, but usually occur within seven days after exposure. The serious
forms of human anthrax are inhalation anthrax, cutaneous anthrax, and
intestinal anthrax. Initial symptoms of inhalation anthrax infection may
resemble a common cold. After several days, the symptoms may progress to
severe breathing problems and shock. Inhalation anthrax is often fatal,
even with the use of antibiotics. Currently, antibiotics are the only drugs
available for therapeutic or prophylactic use, and post-exposure
prophylaxis is the only FDA-approved indication for such products. However,
antibiotic therapy, while useful, is associated with a number of
limitations, including: (1) lack of activity against the toxins produced by
the B. anthracis bacteria (2) need for long- term dosing to achieve full
protection complicated by side effects and non- compliance (3) lack of
efficacy when administered late in the anthrax disease cycle, and (4) lack
of effectiveness of current antibiotics against multi-drug resistant or
genetically engineered strains of anthrax.
About PharmAthene, Inc.
PharmAthene, a privately-held biotechnology company, was formed to meet
the critical needs of the United States by developing and commercializing
medical countermeasures against biological and chemical weapons.
PharmAthene's lead programs include Valortim(TM) for the prevention and
treatment of anthrax infection and Protexia(R) for the prevention and
treatment of morbidity and mortality associated with exposure to chemical
nerve agents. For more information on PharmAthene, please visit
http://www.PharmAthene.com.
In January 2007, PharmAthene announced that it had signed a definitive
merger agreement with Healthcare Acquisition Corp. (Amex: HAQ). HAQ has
filed with the Securities and Exchange Commission a definitive proxy
statement in connection with the proposed merger transaction involving
PharmAthene.
HAQ and its directors and executive officers as well as PharmAthene and
its directors and executive officers may be deemed to be participants in
the solicitation of proxies for the special meeting of HAQ's stockholders
to be held to approve the proposed merger. Security holders and other
interested persons are urged to read the definitive proxy statement
regarding the proposed merger filed with the securities and exchange
commission on July 13, 2007 as it contains important information about the
proposed merger. HAQ's definitive proxy statement has been mailed to HAQ's
stockholders as of a record date established for voting on the proposed
merger. Stockholders may also obtain a copy of the definitive proxy
statement, without charge, by directing a request to HAQ at: 2116 Financial
Center, 666 Walnut Street, Des Moines, Iowa 50309. The definitive proxy
statement and the final prospectus and other SEC filings of HAQ can also be
obtained, without charge, at the securities and exchange commission's
internet site (http://www.sec.gov).
HAQ and PharmAthene claim the protection of the safe harbor for
"forward- looking statements" within the meaning of the private securities
litigation reform act of 1995. Forward-looking statements are statements
that are not historical facts. Such forward-looking statements, based upon
the current beliefs and expectations of management of HAQ and PharmAthene
regarding, among other things, the business of PharmAthene and the merger,
are subject to risks and uncertainties, which could cause actual results to
differ from the forward-looking statements. Risks and uncertainties include
risks associated with the reliability of the results of the initial work
conducted on Valortim(tm) relating to animal efficacy, human safety and
likelihood of successful development of an efficient and scalable
manufacturing process, unexpected funding delays by NIAID, unforeseen
safety issues resulting from the handling of Bacillus anthracis, unforeseen
safety issues resulting from the administration of Valortim (MDX-1303) in
human subjects, uncertainties related to product manufacturing. There can
be no assurance that such development efforts will succeed or that other
developed products will receive required regulatory clearance or that, even
if such regulatory clearance were received, such products would ultimately
achieve commercial success.
About Medarex, Inc.
Medarex is a biopharmaceutical company focused on the discovery,
development and potential commercialization of fully human antibody-based
therapeutics to treat life-threatening and debilitating diseases, including
cancer, inflammation, autoimmune disorders and infectious diseases. Medarex
applies its UltiMAb(R) technology and product development and clinical
manufacturing experience to generate, support and potentially commercialize
a broad range of fully human antibody product candidates for itself and its
partners. More than 30 of these therapeutic product candidates derived from
Medarex technology are in human clinical testing or have had INDs submitted
for such trials, with seven of the most advanced product candidates
currently in Phase III clinical trials. Medarex is committed to building
value by developing a diverse pipeline of antibody products to address the
world's unmet healthcare needs. For more information about Medarex, visit
its website at http://www.medarex.com.
Statement on Cautionary Factors
For Medarex: Except for the historical information presented herein,
matters discussed herein 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"; or similar statements are
forward-looking statements. Medarex disclaims, however, any intent or
obligation to update these forward-looking statements. Risks and
uncertainties include risks associated with the reliability of the results
of the initial work conducted on Valortim(TM) (MDX-1303) relating to animal
efficacy, human safety and likelihood of successful development of an
efficient and scalable manufacturing process, unexpected funding delays by
NIAID, unforeseen safety issues resulting from the handling of Bacillus
anthracis, unforeseen safety issues resulting from the administration of
Valortim in human subjects, uncertainties related to product manufacturing
as well as risks detailed from time to time in Medarex's public disclosure
filings with the U.S. Securities and Exchange Commission (SEC), including
its Annual Report on Form 10-K for the fiscal year ended December 31, 2006
and its quarterly reports on Form 10- Q. There can be no assurance that
such development efforts will succeed or that other developed products will
receive required regulatory clearance or that, even if such regulatory
clearance were received, such products would ultimately achieve commercial
success. Copies of Medarex's public disclosure filings are available from
its investor relations department.
Medarex(R), the Medarex logo and UltiMAb(R) are registered trademarks
of Medarex, Inc. All rights are reserved. Valortim(TM) is a trademark of
PharmAthene, Inc. All rights are reserved.
SOURCE Medarex, Inc.
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Related links:
http://www.medarex.com
http://www.PharmAthene.com
http://www.prnewswire.com/comp/108265.html /
CONTACT:
Laura S. Choi, Investor Relations, Ext. 2216,
or Jean Mantuano, Corporate Communications media, Ext. 2221, both
of Medarex, Inc., +1-609-430- 2880; or Stacey Jurchison,
Director, Corporate Communications of PharmAthene, Inc.,
+1-410-269-2610, jurchisons@pharmathene.com
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