Combination of 90Y-Epratuzumab and Veltuzumab is Active in Non-Hodgkin Lymphoma

Combination of 90Y-Epratuzumab and Veltuzumab is Active in Non-Hodgkin
Lymphoma

Results on Potential New Treatment Regimen Presented at SNMMI 2013 Annual
Meeting

VANCOUVER, British Columbia, June 11, 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 reported that
epratuzumab labeled with the radioisotope, yttrium-90 (^90Y), given in small
doses in combination with veltuzumab is therapeutically active in patients
with aggressive non-Hodgkin lymphoma (NHL). Results from this multicenter
study were presented by Michael B. Tomblyn, MD, of H. Lee Moffitt Cancer
Center in Tampa, FL.

Despite the advent of immunotherapy with anti-CD20 antibody for B-cell
malignancies, aggressive NHLs remain a challenge, requiring the addition of
chemotherapy. An attractive prospect for NHL therapy is to combine
immunotherapy with radioimmunotherapy (RIT) targeting a different B-cell
antigen. Since CD20 and CD22 are distinct antigens, anti-CD20 antibodies
should not cross-block anti-CD22 RIT in such a treatment regimen.

In a previous clinical study, anti-CD22 RIT with ^90Y-epratuzumab has produced
results that are comparable to other interventions.^1 Moreover, given that the
anti-CD20 veltuzumab also compared well to published results with
rituximab,^2,3 the Company is conducting a Phase I/II study to evaluate the
potential of ^90Y-epratuzumab combined with veltuzumab in patients with
aggressive NHL.

Results from 18 patients with various types of aggressive NHL who had failed 1
or more prior standard therapies were reported at the medical conference.
Based upon prior study of ^90Y-epratuzumab given alone in mostly indolent NHL
patients, 2 infusions at 15 mCi/m^2 were the initial dosage. However,
^90Y-doses were lowered due to dose-limiting thombocytopenia and neutropenia,
although most counts recovered within 1 – 8 weeks with no cases of
transfusion-dependent thrombocytopenia. Maximum tolerated dose was determined
as 2 infusions at 6 mCi/m^2. One patient withdrew before evaluation due to a
severe adverse event.

The overall objective response rate among 17 patients who have had treatment
response assessments was 53% (9/17), with 2 patients (17%) reporting a
complete response (CR). One of the CR patients improved from a partial
response (PR) after being retreated with ^90Y-epratuzumab. The other complete
responder is continuing at 18 months. The combination is active in all NHL
subgroups and across all ^90Y-dose levels tested and IPI scores. At the
maximum tolerated dose of 6 mCi/m^2 x 2, 5 of 6 patients (83%) reported a PR
or better.

"We are very encouraged by these early efficacy results, especially in light
of the current low dose of ^90Y," remarked Cynthia L. Sullivan, President and
Chief Executive Officer of Immunomedics. "The Phase II part of this study is
now underway," Ms. Sullivan added.

This study was supported in part by Award Number R44CA139668 from the National
Cancer Institute. The content is solely the responsibility of the Company and
does not necessarily represent the official views of the National Cancer
Institute or the National Institutes of Health.

Treatment responses
                      Number of Objective    Complete     Partial      Stable
Subgroups             Patients  Response (%) Response (N) Response (N) Disease
                                                                       (N)
Histology
Diffuse large B-cell  8         50%          2            2            1
lymphoma
Mantle cell lymphoma  5         20%          0            1            3
Transformed           4         100%         0            4            0
follicular lymphoma
^90Y Dose Level                                                    
12 + 15 mCi/m^2      5         60%          1            2            1
9 mCi/m^2            6         17%          0            1            3
6 mCi/m^2            6         83%          1            4            0
International
Prognostic Index                                                   
Scores
High-Int/High (3-4)   8         25%          1            1            3
Low/Low-Int (0-2)     9         78%          1            6            1

Reference

1.Morschhauser F., Kraeber-Bodéré F., Wegener W.A., Harousseau J.L.,
    Petillon M.O., Huglo D., Trümper L.H., Meller J., Pfreundschuh M., Kirsch
    C.M., Naumann R., Kropp J., Horne H., Teoh N., Le Gouill S., Bodet-Milin
    C., Chatal J.F., Goldenberg D.M. High rates of durable responses with
    anti-CD22 fractionated radioimmunotherapy: results of a multicenter, phase
    I/II study in non-Hodgkin's lymphoma. J Clin Oncol. 2010 Aug
    10;28(23):3709-16. doi: 10.1200/JCO.2009.27.7863. Epub 2010 Jul 12.
2.Morschhauser F,. Leonard J.P., Fayad L., Coiffier B., Petillon M.O.,
    Coleman M., Schuster S.J., Dyer M.J., Horne H., Teoh N., Wegener W.A.,
    Goldenberg D.M. Humanized anti-CD20 antibody, veltuzumab, in
    refractory/recurrent non-Hodgkin's lymphoma: phase I/II results. J Clin
    Oncol. 2009 Jul 10;27(20):3346-53. doi: 10.1200/JCO.2008.19.9117. Epub
    2009 May 18.
3.Negrea G.O., Elstrom R., Allen S.L., Rai K.R., Abbasi R.M., Farber C.M.,
    Teoh N., Horne H., Wegener W.A., Goldenberg D.M. Subcutaneous injections
    of low-dose veltuzumab (humanized anti-CD20 antibody) are safe and active
    in patients with indolent non-Hodgkin's lymphoma. Haematologica. 2011
    Apr;96(4):567-73. doi: 10.3324/haematol.2010.037390. Epub 2010 Dec 20.

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.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, 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 223 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 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, 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: Dr. Chau Cheng
         Senior Director, Investor Relations & Grant Management
         (973) 605-8200, extension 123
         ccheng@immunomedics.com