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The House Committee on Energy and Commerce
Subcommittee on Oversight and Investigations
May 7, 2003
2:00 PM
2123 Rayburn House Office Building
I
will try to give you a very brief snapshot of how a particular class of
biotechnology products (monoclonal antibodies) could play a role in preventing
SARS infections. And, in particular, how one US biotechnology company in
partnership with a non-profit publicly owned research and manufacturing group
are working together in this effort. I will try to leave you with Three
take-home messages:
1.
Monoclonal antibody technology is one of the tools of modern biotechnology that
can be employed to combat the SARS virus.
2.
Finding new medicines is never a quick fix; however, we will be working as
rapidly as possible.
3. The government can play a role in
facilitating the efforts of biotechnology companies in the emerging disease
area.
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Medarex
is collaborating with the Massachusetts Biologic Laboratories (MBL) to
develop a monoclonal antibody to prevent Coronavirus associated SARS.
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Medarex
is a publicly listed US biotechnology company with facilities in NJ and CA.
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MBL,
University of Massachusetts Medical School is the only non-profit
FDA-licensed manufacturer of vaccines and other biologic products in the
United States. MBL has seven FDA licensed vaccines and/or polyclonal
antibody products. In addition MBL has manufactured 4 monoclonal antibodies
for clinical trials in collaboration with NIH and/or private collaborations.
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Antibodies
are a critical component of the body's immune defense against viruses and
other infectious agents.
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Vaccines
stimulate the body to produce antibodies that will recognize a particular
virus.
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In
the absence of an effective vaccine, monoclonal antibodies (i.e.,
genetically engineered antibodies) can potentially provide protection from
infection.
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Antibody
based therapies have been employed since their first discovery over a
hundred years ago by Kitasano and Behring.
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The
first such therapies used serum from immunized large animals such as horses
and sheep.
Human and animal serum products are still used
today; however, we now have new tools that allow for the development of
genetically engineered-monoclonal-antibody based therapeutic drugs.
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There
are now 12 monoclonal antibody based therapeutic products that are approved
by the FDA.
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The
12 monoclonal antibody based therapeutic products are used in a variety of
indications, including cancer, heart disease, arthritis, and infectious
diseases.
One of these monoclonal antibodies, Synagis® (MedImmune,
Gaithersburg MD), is directed against a virus called Respiratory Syncytial Virus
(RSV).
Synagis® was developed as a safe (non-blood
product derived) and consistent (molecularly characterized) alternative to a
human serum derived therapy, RespiGam®.
The success of Synagis® suggests that a similar
monoclonal antibody-based therapeutic may be useful for preventing SARS
infections.
Medarex is focused primarily on the development
of monoclonal antibodies derived from its own proprietary technology for the
generation of human monoclonal antibodies.
This technology uses genetically engineered
strains of mice that carry human immune system genes within their genomes
There are now 10 different human antibody based
drugs in human clinical testing based on Medarex's technology. Some are
being developed by Medarex and others by major pharmaceutical companies like
Novartis and Johnson & Johnson.
To
develop a SARS drug, Medarex and MBL plan to:
1.
Immunize transgenic mice with SARS virus antigens
2.
Generate a panel of potential therapeutic candidates
3.
Test these candidates for their ability to neutralize the SARS virus
4.
Select a lead candidate
5.
Develop a recombinant manufacturing cell line that produces large
quantities of the lead candidate.
6.
Test this material for safety in animals and humans
7.
Test for efficacy in humans.
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The
first 5 steps may be completed in as little as two years. The
development of laboratory and animal model assays for step 3 will be
critical.
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Human efficacy
testing will probably be the most time consuming step
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How
do biotech companies make pipeline decisions?
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Resources
are scarce and must be allocated based on calculated value of future
products
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The
value of future products is derived from estimates of chance of success,
time to development, cost of goods, price of drug, size of market, and
competition
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For
emerging disease indications it is very difficult to calculate a risk
adjusted value for a future product (for SARS we do not yet know enough to
calculate any of the above with a reasonable degree of certainty).
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The
government can play a role to encourage biotech and pharmaceutical companies
in this area by removing some uncertainties (such as establishing a defined
market) or by underwriting some of the research and development costs.
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