- New DNL Products Bind to Both CD20 and CD22 Antigens -
ATLANTA, June 5 /PRNewswire-FirstCall/ -- Immunomedics, Inc. (Nasdaq:
IMMU), a biopharmaceutical company focused on developing monoclonal
antibodies, and its wholly owned subsidiary, IBC Pharmaceuticals, Inc.,
today reported the construction of two new bispecific antibodies that bind
to both CD20 and CD22 antigens on B lymphocytes. A poster describing the
design, characterization and in vitro activity in lymphoma cell lines of
the CD20/CD22 bispecific antibodies was presented at the 42nd Annual
Meeting of the American Society of Clinical Oncology (ASCO) in Atlanta,
Georgia.
Designated as TF3 and TF5, the new bispecific constructs were created
using the Dock and Lock (DNL) method recently published in the Proceedings
of the National Academy of Sciences (please refer to
http://www.immunomedics.com/news_pdf/2006_PDF/PR04252006.pdf), and was
developed by a team of scientists at Immunomedics and IBC Pharmaceuticals.
Both constructs were fully humanized, comprised of Immunomedics' humanized
anti-CD20 (hA20) antibody and humanized anti-CD22 antibody, epratuzumab.
TF3 is made up of two anti-CD20 antibody fragments linked to one anti-CD22
antibody fragment, whereas TF5 was constructed by fusing two anti-CD22
antibody fragments to one anti-CD20 fragment.
TF3 and TF5 were shown to be stable in both human and mouse sera. Both
bispecific antibodies inhibited the growth of human lymphoma cell lines in
vitro. Under the same experimental conditions, TF3 showed a 1000-fold
higher potency as compared to the parent antibody, hA20, which also
reflects a higher cytotoxicity over rituximab, since hA20 was shown to be
similar in activity to rituximab in an article published by Stein and
coworkers in the April 15, 2004, issue of Clinical Cancer Research. The
anti-proliferative activity of TF3 and TF5 is attributed to the ability of
the two bispecific antibodies to cross-link CD20 and CD22. These
encouraging studies are now being expanded to compare these bispecific
antibodies to epratuzumab, hA20, and rituximab in animal models of human
lymphoma, with the intention of bringing the best construct into clinical
testing.
"This research confirms our conviction and expanding patent portfolio
involving the development and use of bispecific antibodies for improved
cancer therapy, which we believe introduces a new paradigm in the
immunotherapy of cancer," commented Cynthia L. Sullivan, President and
Chief Executive Officer of Immunomedics. "It also validates our recently
described DNL platform technology for making stable fusion proteins, in
this case comprising bispecific or bifunctional antibodies for use in
cancer therapy," she added.
Recently, the anti-CD22 humanized antibody, epratuzumab, has also shown
activity in NHL, particularly when combined with rituximab, as well as a
monotherapy in patients with lupus or primary Sjogren's syndrome. It is
believed that epratuzumab's mechanism of action differs from that of
rituximab by showing less B-cell depletion and more B-cell modulation.
Given that these antibodies are directed against different B-cell targets
and appear to function differently, it was hypothesized that a bispecific
antibody targeting both B-cell antigens might show improved activity as
compared to each parent antibody by itself.
About the Dock and Lock (DNL) Method
The DNL method is a platform technology that utilizes the natural
interaction between two proteins, cyclic AMP-dependent protein kinase (PKA)
and A-kinase anchoring proteins (AKAPs). The region that is involved in
such interaction for PKA is called the dimerization and docking domain
(DDD), which always appears in pairs. Its binding partner in AKAPs is the
anchoring domain (AD). When mixed together, DDD and AD will bind with each
other spontaneously to form a binary complex, a process termed docking.
Once "docked," certain amino acid residues incorporated into DDD and AD
will react with each other to "lock" them into a stably tethered structure.
The outcome of the DNL method is the exclusive generation of a stable
complex, in a quantitative manner that retains the full biological
activities of its individual components. Diverse proteins, peptides, and
nucleic acids are among suitable components that can be linked to either
DDD or AD. Since DDD always appears in pairs, any component that is linked
to DDD will have two copies present in the final products.
About IBC Pharmaceuticals
IBC is a development-stage biopharmaceutical company focused on the
development and commercialization of proprietary pretargeting agents for
the detection and treatment of various cancers and other serious diseases.
These products are based on IBC's patented technology platform referred to
as the "Affinity Enhancement System," or AES. The Company currently has
several product candidates in pre-clinical and clinical development, and is
extending its pretargeting technology to include bispecific antibodies made
by the "dock and lock" method.
About Immunomedics
Immunomedics is a New Jersey-based biopharmaceutical company focused on
the development of monoclonal, antibody-based products for the targeted
treatment of cancer, autoimmune and other serious diseases. We have
developed a number of advanced proprietary technologies that allow us to
create humanized antibodies that can be used either alone in unlabeled or
"naked" form, or conjugated with radioactive isotopes, chemotherapeutics or
toxins, in each case to create highly targeted agents. Using these
technologies, we have built a pipeline of therapeutic product candidates
that utilize several different mechanisms of action. Our lead product
candidate, epratuzumab, which development, manufacture and
commercialization rights we have licensed to UCB, S.A. for the treatment of
all autoimmune indications worldwide, is currently in two pivotal Phase III
trials for the treatment of patients with moderate and severe lupus
(ALLEVIATE A and B). At present, there is no cure for lupus and no new
lupus drug has been approved in the U.S. in the last 40 years. We believe
that our portfolio of intellectual property, which includes approximately
90 patents issued in the United States, and more than 250 other issued
patents worldwide, protects our product candidates and technologies. Visit
our web site at http://www.immunomedics.com. We also have a majority
ownership in IBC Pharmaceuticals, Inc., which is developing a novel dock
and lock platform technology, and a new method of delivering imaging and
therapeutic agents selectively to disease, especially different solid
cancers (colorectal, lung, pancreas, etc.), by proprietary, antibody-based,
pretargeting methods.
This release, in addition to historical information, may contain
forward- looking statements made pursuant to the Private Securities
Litigation Reform Act of 1995. Such statements, including statements
regarding clinical trials, out-licensing arrangements (including the timing
and amount of contingent payments), and capital raising activities, involve
significant risks and uncertainties and actual results could differ
materially from those expressed or implied herein. Factors that could cause
such differences include, but are not limited to, risks associated with new
product development (including clinical trials outcome and regulatory
requirements/actions), competitive risks to marketed products and
availability of required financing and other sources of funds on acceptable
terms, if at all, as well as the risks discussed in the Company's filings
with the Securities and Exchange Commission. The Company is not under any
obligation, and the Company expressly disclaims any obligation, to update
or alter any forward-looking statements, whether as a result of new
information, future events or otherwise.
For More Information:
Dr. Chau Cheng
Associate Director, Investor Relations & Business Analysis
(973) 605-8200, extension 123
ccheng@immunomedics.com
SOURCE Immunomedics, Inc.
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Related links:
http://www.Immunomedics.com
http://www.prnewswire.com/comp/113121.html /
CONTACT:
Dr. Chau Cheng, Associate Director, Investor
Relations & Business Analysis, +1-973-605-8200, extension 123,
ccheng@immunomedics.com
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