Immunomedics Reports Updated Results of Labetuzumab-SN-38 in Metastatic Colorectal Cancer

Immunomedics Reports Updated Results of Labetuzumab-SN-38 in Metastatic
Colorectal Cancer

AMSTERDAM, Netherlands, Sept. 30, 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 presented encouraging
results from a Phase I dose-escalation trial of its proprietary antibody-drug
conjugate (ADC), labetuzumab-SN-38, or IMMU-130, in patients with metastatic
colorectal cancer. Dr. Neil H. Segal at the Memorial Sloan-Kettering Cancer
Center, New York, NY, reported the updated results at The European Cancer
Congress 2013 in Amsterdam, The Netherlands.

Results from 15 very advanced patients who were progressing after prior
therapies, including irinotecan, were presented at the Congress. Only 5
patients to-date have been evaluated after completing therapy with 4 or more
doses of the ADC, administered once every 2 weeks, with the rest having
advancing disease that precluded further therapy. Even at this early stage of
clinical development, IMMU-130 has produced a partial response in 1 patient
with a duration of response of 4.7 months, or 140 days. This patient had
failed multiple prior therapies, including irinotecan.

"We are encouraged by these early results, which appear to show that IMMU-130
is well tolerated within a clinically effective dosage range, and may be
active even after its parent molecule, irinotecan, proved to be ineffective,"
commented Cynthia L. Sullivan, President and Chief Executive Officer of
Immunomedics. "A concurrent trial of IMMU-130 with twice-weekly dosing has
shown, in the first two patients evaluated by CT, shrinkage of index lesions
by 27% and 29%, suggesting that more frequent dosing of IMMU-130 may be more
efficacious," Ms. Sullivan added.

The maximum tolerated dose for the once-every-2-weeks dosing schedule has been
confirmed to be below 24 mg/kg. This study has moved to a dose expansion stage
to evaluate lower doses given once or twice weekly. About 10 clinical sites
may participate in this new study. No human anti-humanized antibodies have yet
been detected. Serum analysis revealed a quicker removal of the intact
conjugate compared with the parent antibody, due in part to the intended
release of SN-38 from the ADC.

About Labetuzumab-SN-38 (IMMU-130)

Labetuzumab-SN-38 is one of three agents from the Company's robust ADC program
that are in clinical development. Labetuzumab is a slowly-internalizing
antibody that recognizes the carcinoembryonic antigen (CEA; CEACAM5 or CD66e),
which is expressed in many solid cancers, including more than 80% of
colorectal cancer. In prior clinical trials, the antibody was shown to be safe
when administered unconjugated or bound to the radioisotope, iodine-131, for

SN-38 is the active metabolite of irinotecan, which is a standard therapy for
patients with metastatic colorectal cancer, but has major gastrointestinal and
hematologic toxicity. By targeting SN-38 directly to CEA-expressing tumors,
delivery of SN-38 may be increased while mitigating systemic toxicity.
Preclinical studies have shown that the antibody-drug linkage was susceptible
to cleavage in serum, with 50% of SN-38 released in ~1.0 day, leading to a
locally enhanced concentration within the tumor site. In animal models of
human colorectal cancer, the ADC exhibited high anti-tumor activity.

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, we are planning to launch a Phase III pivotal trial for clivatuzumab
labeled with a radioisotope in advanced pancreatic cancer patients. Other
solid tumor therapeutics in Phase II clinical development include 2
antibody-drug conjugates, labetuzumab-SN-38 (IMMU-130) and hRS7-SN-38
(IMMU-132).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 228 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 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, 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 our licensing partners for the further development of epratuzumab 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.

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