Immunomedics Announces Two New Patent Awards

Second U.S. Patent for Dock-and-Lock Technology

Patent for Combinational Immunotherapy Involving Milatuzumab and
Veltuzumab
MORRIS PLAINS, N.J., May 19, 2009 (GLOBE NEWSWIRE) -- Immunomedics, Inc.
(Nasdaq:IMMU), a biopharmaceutical company focused on developing monoclonal
antibodies to treat cancer and other serious diseases, announced that IBC
Pharmaceuticals, Inc., a majority-owned subsidiary (IBC), has received notice
that its patent application for "Methods and compositions for generating
bioactive assemblies of increased complexity and uses," will issue as U.S.
patent no. 7,534,866 today.

"This is the second patent from a series of applications aimed at protecting our
Dock-and-Lock (DNL) invention. The new patent, which provides coverage into the
year 2026, concerns the construction of more complex multivalent protein
derivatives, including vaccines," said Cynthia L. Sullivan, President and CEO.

DNL features a pair of linker modules known as dimerization and docking domain
(DDD) and anchoring domain (AD) that naturally bind with each other. The new
patent covers methods and compositions of two pairs of DDD and AD such that DDD
from one pair does not cross-interact with AD from the other pair. This allows
the site-specific attachment of more than one biologically active molecule to a
protein in a typical DNL manner - clean, facile and quantitative.

In addition, the Company has also received notice that its patent application
"Immunotherapy of B cell malignancies and autoimmune diseases using unconjugated
antibodies and conjugated antibodies and antibody combinations and fusion
proteins," will issue as U.S. patent no. 7,534,427 today. This patent covers the
use of anti-CD74 and anti-CD20 antibodies in combination for the therapy of
lymphomas and leukemia until the year 2024.

The Company previously reported that combining milatuzumab with rituximab
prolonged survival of animals injected with human mantle cell lymphoma (Please
refer to www.immunomedics.com/news_pdf/2008_PDF/PR12092008.pdf).

About the Dock and Lock Method (DNL)

DNL 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 drugs, chemical polymers, 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 Immunomedics

Immunomedics is a New Jersey-based biopharmaceutical company primarily 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 also have a majority ownership in IBC Pharmaceuticals,
Inc., which is developing a novel Dock-and-Lock (DNL) methodology with us for
making fusion proteins and multifunctional antibodies, 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. We believe that our portfolio of
intellectual property, which includes approximately 134 patents issued in the
United States and more than 300 other patents issued worldwide, protects our
product candidates and technologies. For additional information on us, please
visit our website at www.immunomedics.com. The information on our website does
not, however, form a part of this press release.

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), forecasts of future operating results, 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), our dependence on our licensing partners for the further
development of epratuzumab for autoimmune indications and veltuzumab for
non-cancer indications, 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.

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CONTACT: Immunomedics, Inc.
Dr. Chau Cheng, Associate Director, Investor Relations &
Business Analysis
(973) 605-8200, extension 123
ccheng@immunomedics.com