Immunomedics Reports That UCB Announces New Results From Phase 2B Open-Label Extension Study Evaluating the Long-Term Effects of

Immunomedics Reports That UCB Announces New Results From Phase 2B Open-Label
Extension Study Evaluating the Long-Term Effects of Epratuzumab in SLE

• Relative to the 12-week, double-blind EMBLEM™ study, primary outcome data
from the open-label extension identified no new safety or tolerability
signals^1
• Relative to EMBLEM™ baseline, secondary outcome data from the open-label
extension indicated that the efficacy of epratuzumab, as measured by reduction
in disease activity, was maintained for over two years^2
• Relative to EMBLEM™ baseline, secondary outcome data indicated that
treatment over two years with epratuzumab was associated with decreases in
corticosteroid use in patients receiving >7.5 mg/day^1
• Epratuzumab is an investigational medicine in clinical development and is
not approved for the treatment of systemic lupus erythematosus (SLE)^3

MORRIS PLAINS, N.J., June 13, 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 UCB (Brussels:UCB),
announced new data from an open-label extension (SL0008) of the EMBLEM™ phase
2b study evaluating the long-term effects of epratuzumab treatment in adult
patients with moderate-to-severe systemic lupus erythematosus (SLE). The
primary outcome of outcome of the open-label extension was to assess the
safety of epratuzumab in patients with SLE.^4

Relative to the 12 week, double-blind, placebo-controlled EMBLEM™ study, data
from the open-label, long-term extension identified no new safety or
tolerability signals.^1 In addition, relative to EMBLEM™ baseline values,
secondary outcome data indicated that the efficacy of epratuzumab as measured
by reduction in disease activity was maintained over two years.^2 Secondary
outcome data also indicated that relative to EMBLEM™ baseline values,
treatment over two years with epratuzumab was associated with decreases in
corticosteroid use in patients receiving >7.5 mg/day.^1 These data were
presented this week at the European League Against Rheumatism 2013 Congress in
Madrid, Spain.

Epratuzumab, licensed from the Company to UCB, is an investigational medicine
and the first CD-22/B-Cell receptor (BCR) targeted monoclonal antibody to be
evaluated in clinical studies for the treatment of SLE. Also known as lupus,
SLE is a complex, systemic autoimmune disease that affects many different
organ systems, including the skin, joints, lungs, kidneys and blood.^3,5

"In EMBLEM™, a dose-ranging, phase 2b study, reduction in disease activity was
observed in patients treated with epratuzumab," said Professor Daniel J
Wallace MD, Clinical Professor of Medicine, Cedars-Sinai Medical Center,
California, US. "This double-blind study had a relatively short 12-week,
placebo-controlled, treatment period and it was important to accumulate
long-term data on epratuzumab in the treatment of SLE. The phase 2b extension
study adds new two year open-label data on epratuzumab to that already
available from the 12-week, randomized, controlled study."

EMBLEM™ was designed to identify a suitable dosing regimen for epratuzumab.^6
A total of 227 patients with moderate-to-severe SLE received either: placebo,
epratuzumab cumulative dose of 200 mg (100 mg every other week), 800 mg (400
mg every other week), 2400 mg (600 mg weekly), 2400 mg (1200 mg every other
week) or 3600 mg (1800 mg every other week).^3,6 In the open-label extension
203 patients from any arm of the EMBELM™ study received 1200 mg epratuzumab at
weeks 0 and 2 of 12-week cycles.^1,2,7

Data on epratuzumab presented at EULAR 2013

Evaluation of the safety profile of long-term epratuzumab treatment in
patients with moderate-to-severe SLE^1

Safety variables were primary outcome measures in SL0008 and included duration
of exposure, adverse events, infusion reactions and infections.

Exposure to epratuzumab was a median 845 days over a median 10 treatment
cycles. Adverse events (AEs) caused discontinuation in 29 (14.3%) patients.
The most common serious AEs were SLE flare (3.4%), lupus nephritis (2%) and
symptomatic cholelithiasis (1.5%). The most common infections/infestations
were urinary tract infection (24.6%) and upper respiratory tract infection
(23.2%). There were no opportunistic infections and no patterns of specific
serious or severe infections.

Evaluation of long-term efficacy of epratuzumab as measured by reduction in
disease activity in patients with moderate-to-severe SLE^2

Secondary outcome measures in SL0008 included efficacy as measured by
reduction in disease activity, and assessed by: British Isles Lupus Assessment
Group (BILAG) improvement, SLE disease activity index (SLEDAI) score,
Physician Global Assessment (PGA) score and combined treatment response
defined as BILAG improvement without worsening, no SLEDAI worsening and no PGA
worsening, relative to EMBLEM™ baseline.

The median BILAG total score was 25.0 at EMBLEM™ baseline and 9.0 at week 108.
The score was 14.0 at SL0008 screening. Median SLEDAI score was 12.0 at
EMBLEM™ baseline and 4.0 at week 108. The score was 10.0 at SL0008 screening.
The median PGA score was 50.0 at EMBLEM™ baseline and 17.5 at week 108 with a
score of 31.0 at SL0008 screening.

The proportion of patients achieving the combined treatment response was 32.5%
at SL0008 screening (n=203) and 60.3% at week 108 (n=116).

Effect of corticosteroid use of long-term epratuzumab treatment in patients
with moderate-to-severe SLE^1

Corticosteroid doses were monitored throughout SL0008 and was a secondary
outcome measure. Median corticosteroid dose at EMBLEM™ baseline and SL0008
screening was 10.0 mg/day. At week 116, this was 5 mg/day (n=112). Data
indicated that treatment over two years with epratuzumab was associated with
decreases in corticosteroid use in patients receiving >7.5 mg/day with a
corresponding increase in the proportion of patients receiving lower doses or
no longer receiving corticosteroids.

The proportion of patients requiring 7.5-20 mg/day and >20 mg/day decreased
(49.8% and 10.8% at baseline and 33.9% and 8.0% respectively, at week 116) and
the proportion of patients receiving >0–7.5 mg/day or no longer receiving
corticosteroids increased (33.5% and 5.9% at baseline and 45.5% and 12.5%
respectively, at week 116).

Assessment of immunological parameters to long-term epratuzumab treatment^7

Secondary outcome measures in SL0008 also assessed the long-term effect of
epratuzumab treatment on B-cells and other immunological parameters.

Median absolute B-cell count decreased by 50% at week 112, compared to EMBLEM™
baseline. CD22 expression on B-cells remained low relative to EMBLEM™ baseline
throughout SL0008. No consistent trends were seen in median T cell counts,
which remained similar to EMBLEM™ baseline at week 112 and no consistent
trends were observed for IgG or IgA which remained within normal levels. IgM
levels decreased slightly (-0.21 g/L by week 112). At week 48, there was
little correlation between BILAG improvement rate and B-cell levels. The
moderate reduction in B-cell counts and the lack of correlation supports
B-cell modulation rather than depletion as a mode of action for epratuzumab.

Results presented above from the long-term extension of EMBLEM™ should be
viewed in the context of an open-label study without placebo control. Further
studies are warranted to confirm these findings.

About epratuzumab

Epratuzumab, licensed from the Company to UCB, is an investigational medicine
in clinical development for the treatment of SLE. Epratuzumab is the first
monoclonal antibody that targets CD22, a B-cell specific protein which
regulates B-cell activity through the BCR.^3 Epratuzumab is not approved for
the treatment of SLE by any regulatory authority worldwide.

About SLE

SLE or lupus, is a complex, systemic, autoimmune disease that affects many
different organ systems, including the skin, joints, lungs, kidneys and
blood.^5 Disease activity and rate of progression of organ system damage is
highly variable.^3 SLE affects from 20 to 70 people per 100,000 population,
and is rare in childhood.^8 It is 10 times more common in women than men.^8
References

1. Wallace D., Ordi-Ros J., Neuwelt M. et al. Epratuzumab: sustained safety
profile and effect on corticosteroid use on long-term treatment in patients
with moderate-to-severe systemic lupus erythematosus: Results from an open
label, long-term extension study (SL0008). Presented at the European League
Against Rheumatism (EULAR) 2013 Congress. Abstract # THU0277

2. Gordon C., Clowse M., Houssiau F. et al. Epratuzumab maintains improvements
in disease activity for over 2 years in patients with moderate-to-severe
systemic lupus erythematosus: results from an open-label long-term extension
study (SL0008). Presented at the European League Against Rheumatism (EULAR)
2013 Congress. Abstract # THU 0272

3. Wallace D.J., Kalunian K., Petri M.A. et al. Efficacy and safety of
epratuzumab in patients with moderate/severe active systemic lupus
erythematosus: results from EMBLEM, a phase IIb, randomised, double-blind,
placebo-controlled, multicentre study. Ann Rheum Dis. 2013 Jan 12. [Epub ahead
of print]

4. Clinical Trials.gov.
http://clinicaltrials.gov/ct2/show/NCT00660881?term=SL0008&rank=1 Accessed
10th June 2013

5. Goldenberg D.M., Wallace D.J. Epratuzumab in SLE.
http://www.futuremedicine.com/doi/abs/10.2217/ebo.11.86 Accessed 10th June
2013

6. Clinical Trials.gov.
http://clinicaltrials.gov/ct2/show/NCT00624351?term=SL0007&rank=2 Accessed
10th June 2013

7. Strand V., Leszczynski P., Keiserman M. et al. Immunologic response to
long-term epratuzumab treatment in SL0008, an open-label long-term extension
study in patients with moderate-to-severe systemic lupus erythematosus.
Presented at the European League Against Rheumatism (EULAR) 2013 Congress.
Abstract # THU 0286

8. Pons-Estel G.J., Alarcón G.S., Scofield L. et al. Understanding the
epidemiology and progression of systemic lupus erythematosus. Semin Arthritis
Rheum. 2010 Feb;39(4):257-68

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