Immunomedics Reports First Efficacy Results of Subcutaneous Humanized Anti-CD20 Antibody...

Immunomedics Reports First Efficacy Results of Subcutaneous Humanized Anti-CD20
Antibody Therapy of Lymphoma With Veltuzumab

ORLANDO, Fla., June 1, 2009 (GLOBE NEWSWIRE) -- Immunomedics, Inc.
(Nasdaq:IMMU), a biopharmaceutical company focused on developing monoclonal
antibodies to treat cancer and other serious diseases, today announced that
subcutaneous injections of low doses of veltuzumab in patients with
non-Hodgkin's lymphoma (NHL) or chronic lymphocytic leukemia (CLL) produced a
slow and efficient delivery of pharmacologically active antibody into the blood,
that the treatment was well tolerated, and that NHL patients showed objective
responses at all doses tested.

"We believe the subcutaneous formulation offers doctors and patients significant
benefits including ease-of-use, better compliance and lower side effects," said
Cynthia L. Sullivan, President and CEO. "We expect to complete this study before
the end of this calendar year, and are in the process of developing a
registration pathway for veltuzumab in oncology," added Ms. Sullivan.

For the 15 NHL patients reported at the conference, 53% had an objective
response, and 27% a complete response (CR/CRu). In follicular lymphoma, 7 of 12
patients (58%) had objective responses, with 3 patients (25%) having complete
responses. These findings were similar to the Phase I/II results using the
intravenous formulation recently published by the Company (please refer to
www.immunomedics.com/news_pdf/2009_PDF/PR05182009.pdf). Thus, despite the small
number of patients, it appears that the subcutaneous formulation of veltuzumab
can be effective against NHL.

For CLL, there were no objective responses in 8 patients reported at the
conference. However, 50% of patients had stable disease for more than 12 weeks.
An adequate dosing schedule has yet to be determined for this group of patients.

Subcutaneous injections of veltuzumab were given 2 weeks apart for a total of 4
doses. Patients received veltuzumab at one of three dose levels: 80, 160, or 320
mg. Efficacy was assessed at 4 and 12 weeks post treatment, with responding
patients continuing follow-up. The injections were well tolerated with only
transient, mild, grade-1 treatment-related adverse events.

Low doses of subcutaneously administered veltuzumab was also reported previously
to be active in patients with immune thrombocytopenic purpura, an autoimmune
disease, producing durable platelet increases in some patients that are
continuing after one year (please refer to
www.immunomedics.com/news_pdf/2008_PDF/PR12082008A.pdf).

About Veltuzumab

As a second generation humanized anti-CD20 antibody, veltuzumab was constructed
using the same donor frameworks as epratuzumab, the Company's humanized
anti-CD22 antibody. Consequently, similar to epratuzumab, veltuzumab can be
infused rapidly and has been well tolerated by patients. Veltuzumab's
complementarity-determining regions (CDRs) are identical to rituximab, except
for one amino acid residue (aspartic acid instead of asparagine) in CDR3's heavy
chain variable region. Veltuzumab demonstrated slower off-rates in three human
lymphoma cell lines, and mutation studies confirmed that the difference was
related to the single amino acid change. Although antiproliferative, apoptotic,
and antibody-dependent cellular cytotoxicity effects seemed similar in vitro,
veltuzumab demonstrated increased complement-dependent cytotoxicity in one of
three lymphoma cell lines and was significantly more effective in vivo than
rituximab in three human lymphoma models. Even at low doses, veltuzumab
effectively depleted B cells in cynomolgus monkeys and controlled tumor growth
in mice bearing human lymphoma xenografts.

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