Human Genome Sciences and GlaxoSmithKline Announce Positive Phase 3 Study Results for BENLYSTA(TM) in Systemic Lupus Erythematosus

Rockville, Maryland and London (ots/PRNewswire) -

- BENLYSTA (belimumab) met its primary efficacy endpoint by
achieving a statistically significant improvement in patient
response rate versus placebo in BLISS-52 -

- First drug for lupus to reach this advanced stage of clinical
development and achieve positive results, in the largest randomized
placebo-controlled clinical trial ever completed in SLE patients -

Human Genome Sciences, Inc. (Nasdaq: HGSI) and GlaxoSmithKline
PLC (GSK) today announced that BENLYSTA(TM) (belimumab, formerly
LymphoStat-B(R)) met the primary endpoint in BLISS-52, the first of
two pivotal Phase 3 trials in patients with serologically active
systemic lupus erythematosus (SLE). In the placebo-controlled
BLISS-52 study, the results showed that belimumab plus standard of
care achieved a clinically and statistically significant improvement
in patient response rate at Week 52, compared with standard of care
alone. Study results also showed that belimumab was generally well
tolerated, with adverse event rates comparable between belimumab and
placebo treatment groups.

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"The BLISS-52 results demonstrated that BENLYSTA has the
potential to become the first new approved drug in decades for people
living with systemic lupus," said H. Thomas Watkins, President and
Chief Executive Officer, HGS. "Given the limited treatment options
currently available, patients would benefit greatly from potential
new treatments. BENLYSTA is an outstanding example of the type of
treatment HGS is working to develop and bring to patients. Assuming
positive results in November from our second Phase 3 trial of
BENLYSTA, we and GSK plan to submit marketing applications in the
United States, Europe and other regions in the first half of 2010."

Belimumab is an investigational drug and the first in a new class
of drugs called BLyS-specific inhibitors. No new drug for lupus has
been approved by regulatory authorities in more than 50 years.
Belimumab is being developed by HGS and GSK under a co-development
and commercialization agreement entered into in August 2006.

"Lupus is a chronic, often debilitating, and sometimes fatal
illness that affects an estimated five million people worldwide and
can have a devastating effect on both patients living with the
disease and their families," said Carlo Russo, M.D., Senior Vice
President, Biopharm Development, GSK. "BENLYSTA is the first medicine
being developed specifically for lupus that has reached this late
stage of clinical development with positive results. We look forward
to completing the pivotal studies, with the hope of bringing this
potentially important therapeutic advance to patients suffering from
SLE."

Key Findings from BLISS-52

"The BLISS-52 results support and extend the findings that
emerged in the serologically active subgroup of SLE patients at Week
52 in our Phase 2 trial," said David C. Stump, M.D., Executive Vice
President, Research and Development, HGS. "We are delighted to report
that the efficacy of treatment with BENLYSTA plus standard of care
was superior in this study to that of placebo plus standard of care,
while the safety profile was comparable overall to placebo. BENLYSTA
met the primary endpoint in this Phase 3 study at a robust level of
statistical significance. BENLYSTA also significantly reduced SLE
disease activity versus placebo based on a number of other measures,
including SELENA SLEDAI and Physician's Global Assessment. Of note, a
greater percentage of patients receiving BENLYSTA achieved a
clinically meaningful reduction in steroid dose. We hope to have a
full presentation of BLISS-52 results at an appropriate scientific
meeting later in 2009."

Topline BLISS-52 results include:
-- Based on an intention-to-treat (ITT) analysis, belimumab met its
primary efficacy endpoint of superiority versus placebo at Week 52.
A clinically and statistically significant improvement was shown in
patient response rate for belimumab plus standard of care, vs.
placebo plus standard of care: 57.6% for 10 mg/kg belimumab, 51.7%
for 1 mg/kg belimumab, and 43.6% for placebo (p=0.0006 and p=0.011
for 10 mg/kg and 1 mg/kg belimumab, respectively vs. placebo).
Patient response was defined by an improvement in SELENA SLEDAI
score of 4 points or greater, no clinically significant BILAG
worsening, and no clinically significant worsening in Physician's
Global Assessment.
Results for each individual component of the patient response rate
were consistent with the overall improvement shown for the primary
endpoint.
-- Results for prespecified major secondary efficacy endpoints were:
-- A significantly greater percentage of patients receiving
belimumab achieved a reduction in SELENA SLEDAI score of at
least 4 points by Week 52, with 58.3% for 10 mg/kg belimumab,
53.% for 1 mg/kg belimumab, and 46.0% for placebo (p=0.0024 and
p=0.019 for 10 mg/kg and 1 mg/kg belimumab, respectively vs.
placebo).
-- Improvement in Physician's Global Assessment (PGA) at Week 24
was greatest in the belimumab 10 mg/kg treatment group versus
placebo (p=0.0003 for 10 mg/kg and p=0.27 for 1 mg/kg belimumab,
respectively) with improvement observed within 4-8 weeks.
-- A higher percentage of patients in both belimumab treatment
groups, versus placebo, had their average prednisone dose
reduced by at least 25% from baseline to 7.5 mg per day or less
during the last 12 weeks of study (p=0.053 for 10 mg/kg and
p=0.025 for 1 mg/kg belimumab, respectively vs. placebo).
-- Improvement in health-related quality of life at Week 24 as
measured by the SF-36 Physical Component Summary (PCS) score was
not significantly different among treatment groups. However,
although not a major secondary endpoint, improvement in the
SF-36 PCS score at Week 52 was significantly greater in both
belimumab treatment groups (p=0.025 for 10 mg/kg and p=0.027 for
1 mg/kg belimumab, respectively vs. placebo).
-- In BLISS-52, belimumab was generally well tolerated, with rates of
overall adverse events, serious adverse events, infections and
fatalities comparable between belimumab and placebo treatment
groups. Serious infections were reported in 5.9% of patients on
placebo and 6.1% of patients on belimumab. The most common adverse
events were headache, arthralgia, upper respiratory tract
infections, urinary tract infection and influenza, and were also
comparable between belimumab and placebo treatment groups. No
malignancies were reported.

Professor Sandra V. Navarra, M.D., a principal investigator and
Head of Rheumatology at the University of Santo Tomas, Manila, The
Philippines, said, "Given the limitations of available therapies,
there is a great need for well tolerated and effective treatments for
lupus. We are very encouraged by the findings of BLISS-52, and look
forward to presenting these results later in the year. We also look
forward to the results of BLISS-76 later this year."

About the BENLYSTA (belimumab) Phase 3 Development Program

The Phase 3 development program for belimumab includes two
double-blind, placebo-controlled, multi-center Phase 3 superiority
trials - BLISS-52 and BLISS-76 - to evaluate the efficacy and safety
of belimumab plus standard of care, versus placebo plus standard of
care, in serologically active (i.e., autoantibody-positive) patients
with SLE. This is the largest clinical trial program ever conducted
in lupus patients. BLISS-52 randomized and treated 865 patients at 90
clinical sites in 13 countries, primarily in Asia, South America and
Eastern Europe. BLISS-76 enrolled and randomized 826 patients at 133
clinical sites in 19 countries, primarily in North America and
Europe. The design of the two trials is similar, but the duration of
therapy in the two studies is different - 52 weeks for BLISS-52 and
76 weeks for BLISS-76. The data from BLISS-76 will be analyzed after
52 weeks in support of a potential Biologics License Application in
the United States and Marketing Authorization Application in Europe
and other regions. HGS designed the Phase 3 program for belimumab in
collaboration with GSK and leading international SLE experts, and the
program is being conducted under a Special Protocol Assessment
agreement with FDA.

The primary efficacy endpoint of BLISS-52 and BLISS-76 is the
patient response rate at Week 52, as defined by: (1) a reduction from
baseline of at least 4 points on the SELENA SLEDAI disease activity
scale (which indicates a clinically important reduction in SLE
disease activity); (2) no worsening of disease as measured by the
Physician's Global Assessment (worsening defined as an increase of
0.30 points or more from baseline); and (3) no new BILAG A organ
domain score (which indicates a severe flare of lupus disease
activity) and no more than one new BILAG B organ domain score (which
would indicate a moderate flare of disease activity). Analysis for
the primary endpoint is based on intention-to-treat (ITT) and
adjusted for baseline stratification factors, including SELENA SLEDAI
score, proteinuria and race.

In each of the two Phase 3 trials, patients were randomized to
one of three treatment groups: 10 mg/kg belimumab (BLISS-52, n=290),
1 mg/kg belimumab (BLISS-52, n=288), or placebo (BLISS-52, n=287).
Patients are dosed intravenously on Days 0, 14 and 28, then every 28
days thereafter for the duration of the study. All receive standard
of care therapy in addition to the study medication. Safety is
reviewed by an independent Data Monitoring Committee throughout both
studies.

About BENLYSTA (belimumab)

Belimumab is an investigational human monoclonal antibody drug
that specifically recognizes and inhibits the biological activity of
B-lymphocyte stimulator, or BLyS(R). BLyS is a naturally occurring
protein discovered by HGS that is required for the development of
B-lymphocyte cells into mature plasma B cells. Plasma B cells produce
antibodies, the body's first line of defense against infection. In
lupus and certain other autoimmune diseases, elevated levels of BLyS
are believed to contribute to the production of autoantibodies -
antibodies that attack and destroy the body's own healthy tissues.
The presence of autoantibodies appears to correlate with disease
severity. Preclinical and clinical studies suggest that belimumab can
reduce autoantibody levels in SLE. BLISS 52 results suggest that
belimumab can reduce SLE disease activity, and a second Phase 3
trial, BLISS-76, is underway to confirm these results.

About the Collaboration with GSK

In August 2006, HGS and GSK entered into a definitive
co-development and co-commercialization agreement under which HGS has
responsibility for conducting the belimumab Phase 3 trials, with
assistance from GSK. The companies will share equally in Phase 3/4
development costs, sales and marketing expenses, and profits of any
product commercialized under the current agreement.

About Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a chronic, life-threatening
autoimmune disease. Approximately five million people worldwide,
including approximately 1.5 million in the United States, suffer from
various forms of lupus, including SLE. Lupus can occur at any age,
but appears mostly in young people ages 15 to 45. About 90 percent of
those diagnosed with lupus are women. African-American women are
about three times more likely to develop lupus, and it is also more
common in Hispanic, Asian and American Indian women. Symptoms may
include extreme fatigue, painful and swollen joints, unexplained
fever, skin rash and kidney problems. Lupus can lead to arthritis,
kidney failure, heart and lung inflammation, central nervous system
abnormalities, inflammation of the blood vessels and blood disorders.
For more information on lupus, visit the Lupus Foundation of America
at www.lupus.org, the Lupus Research Institute at
www.lupusresearchinstitute.org, the National Institute of Arthritis
and Musculoskeletal and Skin Diseases at www.niams.nih.gov, or Lupus
Europe at www.elef.rheumanet.org.

Conference Call

HGS management will hold a conference call to discuss this
announcement today at 8:15 AM Eastern. Investors may listen to the
call by dialing 1-888-632-5010 or +1-913-312-0402, passcode 8364417,
five to 10 minutes before the start of the call. A replay of the
conference call will be available within a few hours after the call
ends. Investors may listen to the replay by dialing 1-888-203-1112 or
+1-719-457-0820, confirmation code 8364417. Today's conference call
also will be webcast and can be accessed at www.hgsi.com. Investors
interested in listening to the live webcast should log on before the
conference call begins to download any software required. Both the
audio replay and the archive of the conference call webcast will
remain available for several days.

About GlaxoSmithKline

GlaxoSmithKline is one of the world's leading research-based
pharmaceutical and healthcare companies, and is committed to
improving the quality of human life by enabling people to do more,
feel better and live longer. For more information, visit
GlaxoSmithKline on the World Wide Web at www.gsk.com.

About Human Genome Sciences

The mission of HGS is to apply great science and great medicine
to bring innovative drugs to patients with unmet medical needs. The
HGS clinical development pipeline includes novel drugs to treat
hepatitis C, lupus, inhalation anthrax and cancer.

The Company's primary focus is rapid progress toward the
commercialization of its two lead drugs, Albuferon(R) (albinterferon
alfa-2b) for hepatitis C and BENLYSTA(TM) (belimumab, formerly
LymphoStat-B(R)) for lupus. Albuferon has now completed Phase 3
development, and the submission of global marketing applications is
expected in fall 2009. BENLYSTA successfully met its primary endpoint
in the first of two Phase 3 trials in systemic lupus erythematosus;
results of the second BENLYSTA Phase 3 trial are expected in November
2009. Also in late-stage development is raxibacumab (ABthrax(TM)) for
the treatment of inhalation anthrax (Biologics License Application
currently pending with the U.S. Food and Drug Administration). In
addition, HGS has substantial financial rights to certain products in
the GSK clinical pipeline including darapladib, currently in Phase 3
development in patients with coronary heart disease, and Syncria(R)
(albiglutide), currently in Phase 3 development in patients with type
2 diabetes.

For more information about HGS, please visit the Company's web
site at www.hgsi.com. Health professionals and patients interested in
clinical trials of HGS products may inquire via e-mail to
clinical_trials@hgsi.com This e-mail address is being protected from
spam bots, you need JavaScript enabled to view it or by calling HGS
at +1-301-610-5790, extension 3550. HGS, Human Genome Sciences,
ABthrax, Albuferon, BENLYSTA, BLyS and LymphoStat-B are trademarks of
Human Genome Sciences, Inc.

HGS Safe Harbor Statement

This announcement contains forward-looking statements within the
meaning of Section 27A of the Securities Act of 1933, as amended, and
Section 21E of the Securities Exchange Act of 1934, as amended. The
forward-looking statements are based on Human Genome Sciences'
current intent, belief and expectations. These statements are not
guarantees of future performance and are subject to certain risks and
uncertainties that are difficult to predict. Actual results may
differ materially from these forward-looking statements because of
the Company's unproven business model, its dependence on new
technologies, the uncertainty and timing of clinical trials, the
Company's ability to develop and commercialize products, its
dependence on collaborators for services and revenue, its substantial
indebtedness and lease obligations, its changing requirements and
costs associated with facilities, intense competition, the
uncertainty of patent and intellectual property protection, the
Company's dependence on key management and key suppliers, the
uncertainty of regulation of products, the impact of future alliances
or transactions and other risks described in the Company's filings
with the Securities and Exchange Commission. In addition, while the
Company has completed delivery of ABthrax to the U.S. Strategic
National Stockpile, the Company will continue to face risks related
to FDA's approval of the Company's Biologics License Application for
ABthrax. If the Company is unable to meet requirements associated
with the ABthrax contract, future revenues from the sale of ABthrax
to the U.S. Government will not occur. Existing and prospective
investors are cautioned not to place undue reliance on these
forward-looking statements, which speak only as of today's date.
Human Genome Sciences undertakes no obligation to update or revise
the information contained in this announcement whether as a result of
new information, future events or circumstances or otherwise.

GlaxoSmithKline Forward-Looking Statements

Under the safe harbor provisions of the US Private Securities
Litigation Reform Act of 1995, GSK cautions investors that any
forward-looking statements or projections made by GSK, including
those made in this announcement, are subject to risks and
uncertainties that may cause actual results to differ materially from
those projected. Factors that may affect GSK's operations are
described under 'Risk Factors' in the 'Business Review' in GSK's
Annual Report on Form 20-F for 2008.

ots Originaltext: Human Genome Sciences, Inc.
Im Internet recherchierbar: http://www.presseportal.de

Contact:
HGS: Media :Jerry Parrott, Vice President, Corporate Communications,
+1-301-315-2777, Investors: Peter Vozzo, Senior Director, Investor
Relations, +1-301-251-6003; GSK: U.K. Media Inquiries: Philip
Thomson, +44-020-8047-5502, David Outhwaite, +44-020-8947-5502,
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Analyst/Investor Inquiries: Tom Curry, +1-215-751-5419, Jen Hill
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