Immunomedics Announces U.S. Patent for Antibody-SN-38 Conjugates

Immunomedics Announces U.S. Patent for Antibody-SN-38 Conjugates

New Patent on F-18 Labeling of Peptides and Proteins Also Issued

MORRIS PLAINS, N.J., Dec. 31, 2013 (GLOBE NEWSWIRE) -- Immunomedics, Inc.
(Nasdaq:IMMU), a biopharmaceutical company primarily focused on the
development of monoclonal antibody-based products for the targeted treatment
of cancer, autoimmune and other serious diseases, today announced the issuance
of U.S. patent no. 8,617,558 for additional claims under the patent family
"Camptothecin-binding moiety conjugates," and U.S. patent no. 8,617,518 with
additional claims for the patent family "Methods and compositions for improved
F-18 labeling of proteins, peptides and other molecules."

Patent 8,617,558 relates to our proprietary linker technology for conjugating
SN-38 to the Company's humanized antibodies for targeted delivery of the
potent drug to the tumor. The patent will expire in December 2023. Additional
patents covering the Company's antibody-drug conjugates are being prosecuted
in major countries worldwide.

"This is a key patent for the protection of our antibody-drug conjugates
patent family, of which IMMU-132, an anti-TROP-2-SN-38 conjugate, and
IMMU-130, an anti-CEACAM5-SN-38 conjugate, constitute two of our most exciting
new agents for solid cancer therapy," commented Cynthia L. Sullivan, President
and Chief Executive Officer. "Both IMMU-132 and 130 are in Phase II clinical
development and we plan to report results from these studies in the second
quarter of 2014 at upcoming scientific and medical conferences."

In early dose-escalation studies, the two antibody-SN-38 conjugates have shown
evidence of tumor shrinkage in patients with difficult-to-treat solid tumors
who had failed multiple prior therapies, including irinotecan.

SN-38 is the active metabolite of irinotecan, a camptothecin analogue approved
for the treatment of metastatic colorectal cancer. While SN-38 is 2 to 3
orders of magnitude more potent than its parent molecule, it does not dissolve
in water and cannot be administered directly to patients. Our unique linker
allows us to produce antibody-SN-38 conjugates that are soluble in water with
excellent yields, as well as preservation of antibody binding and drug
activity, even after attaching about 7 drug molecules per antibody.

The second patent, 8,617,518, which will expire in December 2027, concerns the
methods and compositions of labeling peptides and other molecules with the
diagnostic radioisotope, fluorine-18 (F-18) or the magnetic resonance imaging
(MRI) label, fluorine-19 (F-19).

The Company has invented a simple-to-use kit for the rapid labeling of
peptides and proteins, including antibodies, to be used as imaging agents for
positron-emission tomography (PET) and MRI of diseases. In particular,
antibody-based targeting agents, an area of our strength, for immunoPET
imaging can become a companion diagnostic to our therapeutic products,
including the antibody-drug conjugates currently in clinical trials.

"This is an important technology for us," Ms. Sullivan stated, "and is of
interest to major pharmaceutical companies wanting an imaging companion to
their therapeutics."

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, cytokines 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, is currently in two Phase III clinical trials in lupus. In
oncology, clivatuzumab tetraxetan labeled with a radioisotope is in a Phase
III pivotal trial in advanced pancreatic cancer patients. Other solid tumor
therapeutics in Phase II clinical development include 2 antibody-drug
conjugates, IMMU-132 (anti-TROP-2-SN-38) and IMMU-130 (anti-CEACAM5-SN-38). We
also have a majority ownership in IBC Pharmaceuticals, Inc., which is
developing a novel DOCK-AND-LOCK™ (DNL™) method with us for making fusion
proteins and multifunctional antibodies. DNL™ is being used particularly to
make bispecific antibodies targeting cancers and infectious diseases as a
T-cell redirecting immunotherapy, as well as bispecific antibodies for
next-generation cancer and autoimmune disease therapies. We believe that our
portfolio of intellectual property, which includes approximately 241 active
patents in the United States and more than 400 foreign patents, protects our
product candidates and technologies. Our strength in intellectual property has
resulted in the top-10 ranking in the 2012 IEEE Spectrum Patent Power
Scorecards in the Biotechnology and Pharmaceuticals category. For additional
information on us, please visit our website at The
information on our website does not, however, form a part of this press

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, potential
collaborations, 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 any cash payment that the Company might
receive in connection with a sublicense involving a third party and UCB, which
is not within the Company's control, new product development (including
clinical trials outcome and regulatory requirements/actions), our dependence
on UCB for the further development of epratuzumab 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.

CONTACT: For More Information:
         Dr. Chau Cheng
         Senior Director, Investor Relations & Grant Management
         (973) 605-8200, extension 123
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