Final Therapy and Safety Results From Phase I/II Study of Veltuzumab, a Second-Generation...

Final Therapy and Safety Results From Phase I/II Study of Veltuzumab, a
Second-Generation Anti-CD20 Humanized Antibody, Published

MORRIS PLAINS, N.J., May 18, 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
final results from their Phase I/II study of veltuzumab in patients with
non-Hodgkin's lymphoma (NHL) were published online in the Journal of Clinical
Oncology, entitled "Humanized anti-CD20 antibody, veltuzumab, in
refractory/recurrent non-Hodgkin's lymphoma: phase I/II results," by F.
Morschhauser, J.P. Leonard, L. Fayad, B. Coiffier, M. Petillon, M. Coleman, S.J.
Schuster, M.J.S. Dyer, H. Horne, N. Teoh, W.A. Wegener, and D.M. Goldenberg.

The primary objectives of this open-label, multicenter study were to evaluate
the safety, tolerance, and immunogenicity of veltuzumab with pharmacokinetics,
pharmacodynamics and preliminary evidence of efficacy as secondary objectives.

Eighty-two adult patients with CD20-positive B-cell NHL were enrolled to receive
4 weekly doses of 80 to 750 mg/m(2) of veltuzumab. Fifty-five patients had
follicular lymphoma and 27 had other B-cell lymphomas. Most patients (79%) had
the advanced stages of the disease. All patients had one or more prior standard
chemotherapy or rituximab-containing regimens. Despite short infusion times,
veltuzumab was well tolerated with no grade 3 to 4 drug-related adverse events.

Across all doses and subtypes of NHL, the overall response rate was 41% with 21%
of patients having a complete response. For the 55 patients with follicular
lymphoma, 44% had objective responses with 27% complete responses. The highest
response rates in this subgroup of patients occurred in the small number of
rituximab-naive patients, of which 57% (4 out of 7) had an objective response
and 43% (3 out of 7) completely responded. More importantly, for patients who
had received two or more prior rituximab-regimens, 6 out of 17 (35%) responded
to veltuzumab, including 5 complete responses. In the non-follicular lymphoma
subgroup, the objective response rate was 35%, with a complete response rate of
27%.

Commenting on the results, Cynthia L. Sullivan, President and CEO said, "These
findings are consistent with the structure-function properties of veltuzumab we
have seen in preclinical studies, which indicate certain functional improvements
in the properties of veltuzumab, such as a longer binding to CD20 on lymphoma
cells and improved efficacy compared to an established anti-CD20 antibody. We
believe the combination of excellent tolerability, short infusion times and
anti-cancer activity at low doses indicates that veltuzumab has potentially
significant clinical value." Ms. Sullivan further stated, "Preliminary results
from our Phase I study of subcutaneous veltuzumab in B-cell malignancies will be
presented at the 2009 annual meeting of the American Society of Clinical
Oncology."

At all dose levels studied, B-cell depletion occurred after the first infusion
of veltuzumab which produced mean serum levels of antibody exceeding the 25
microgram/mL value considered important for anti-CD20 therapy. In addition,
veltuzumab remained in circulation after the last infusion, with half-lives that
were similar at all dose levels, and at least as long as those reported in
studies involving rituximab.

Results from this study were presented in part at the 43rd annual meeting of the
American Society of Clinical Oncology.

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). 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