Fusion Proteins Targeting CD20 and CD22 Presented in Two Posters at
American Society of Hematology (ASH) Annual Meeting
ORLANDO, Fla., Dec. 10 /PRNewswire-FirstCall/ -- Immunomedics, Inc.
(Nasdaq: IMMU), a biopharmaceutical company focused on developing
monoclonal antibodies, today announced the development of new multivalent
antibodies against the CD20 and CD22 antigens present on normal and
malignant B- lymphocytes, which showed activities against B-cell lymphomas
in tissue culture and in animal models. Results on these next-generation
protein constructs were presented in two posters at the 48th Annual Meeting
of ASH in Orlando, FL.
The first poster presentation described the characterization of a
bispecific antibody (bsMAb) composed of an intact humanized anti-CD20
antibody, hA20, linked to two single-chain variable fragments (scFvs) of an
anti-CD22 antibody, epratuzumab. Thus, this fusion protein is tetravalent
with 4 binding sites, two for CD20 and two for CD22. This tetravalent bsMAb
was found to have anti-lymphoma activity similar to either hA20 or
epratuzumab in vitro. The studies further demonstrated that the CD20/CD22
bsMAb has a mode of action against B-lymphoma cells distinct from that of
either hA20 or epratuzumab. More importantly, the tetravalent bsMAb was
more effective in improving the survival of mice bearing human lymphomas,
when compared with its parental antibodies, hA20 or epratuzumab.
In a second poster presentation, multiple hexavalent antibodies were
constructed using the Company's proprietary protein engineering platform
technology called the Dock-and-Lock methodology (DNL) by linking an intact
hA20 or epratuzumab to two antigen binding antibody fragments (Fabs) of
hA20 or epratuzumab. The resulting proteins: CD20/CD22 bsMAbs, hexavalent
hA20, and hexavalent epratuzumab, each contain 6 binding arms. In cell
cultures of human B-lymphoma cells, the hexavalent CD20/CD22 bispecific
antibody constructs proved to be 100-times more potent in inhibiting growth
than rituximab, while the hexavalent hA20 antibody was even more active. In
contrast to rituximab or hA20, these new protein constructs lack constant
region (Fc) functions, because no antibody-dependent or complement-mediated
cellular cytotoxicities were observed, thus indicating that these new
antibodies kill lymphoma cells exclusively by signal transduction
mechanisms. Finally, studies with human lymphoma cells growing in mice
showed that these new fusion proteins are very active in controlling tumor
growth and increasing survival, even at very low doses (single injection of
4 micro gram).
In a statement by company President and CEO, Cynthia L. Sullivan:
"These findings demonstrate that the DNL method can make multivalent fusion
proteins that are stable for both in vitro and in vivo applications. More
importantly, because multiple copies of binding sites are built into the
final products, they are more potent than their parental proteins."
"While we have been focusing on using DNL to create more potent
immunotherapy agents because of our expertise in monoclonal antibodies, the
technology is versatile and also can be used to generate multifunctional
binary complexes of proteins other than antibodies. This technology is
particularly suitable for creating protein derivatives where conjugation or
modification with non-protein groups are involved," she further commented.
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. We have recently
licensed our lead product candidate, epratuzumab, to UCB, S.A. for the
treatment of all autoimmune disease indications worldwide. We have retained
the rights for epratuzumab in oncology indications for which UCB has been
granted a buy-in option. UCB has development, manufacture and
commercialization rights, and is responsible for all clinical trials
evaluating epratuzumab for the treatment of patients with moderate and
severe lupus. 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 108
patents issued in the United States, and more than 250 other issued patents
worldwide, protects our product candidates and technologies. We also have a
majority ownership in IBC Pharmaceuticals, Inc., which is developing a
novel dock and lock methodology, 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. Visit our web site at http://www.immunomedics.com.
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 for Immunomedics, Inc.,
+1-973-605-8200 extension 123, or email, ccheng@immunomedics.com
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