UCB and Biogen Idec's Oral VLA-4 Antagonist Enters Phase II Development for Multiple Sclerosis

UCB (Euronext Brussels: UCB) and Biogen Idec (NASDAQ: BIIB) today
announced the initiation of a Phase II study of CDP323 - an oral VLA-4
antagonist - under development for relapsing-remitting multiple
sclerosis (MS). The double-blind, randomized Phase II study commenced
this week with dosing of the first patient. The study is designed to
enroll over 200 patients with relapsing-remitting MS who have failed
earlier treatment with a beta-interferon. Last October the companies
entered an agreement to co-develop and co-commercialize this small
molecule compound.

The trial compares the safety and efficacy of two doses of CDP323
monotherapy to placebo over a period of six months. This is the first
time that patients with MS will be exposed to CDP323. Approximately 50
medical centers in Europe and the U.S. are expected to participate in
this study. The results of this Phase II study are expected by the end
of 2008.

"Multiple sclerosis affects more than a million people worldwide
and so far, no oral treatment has been available. An oral therapy
would represent a significant advance for patients as it could provide
them with a new, non-invasive option of drug delivery," said Professor
Chris Polman, Professor of Neurology, VU Medical Centre, Amsterdam,
the Netherlands, Lead Investigator for this study.

About CDP323

CDP323 is an orally active small molecule VLA-4 antagonist. The
safety, tolerability and pharmacokinetic profile of CDP323 have been
evaluated in healthy volunteers in three separate Phase I studies.
Data from these studies were reported at the 2006 European Committee
for Treatment and Research in Multiple Sclerosis (ECTRIMS). The data
from these early studies supports further development of CDP323.

About Multiple Sclerosis

MS is a chronic disease of the central nervous system that affects
approximately 400,000 people in North America and more than one
million people worldwide. It is a disease that affects more women than
men, with onset typically occurring between 20 and 50 years of age. MS
is caused by damage to myelin, the protective sheath surrounding nerve
fibers in the central nervous system, which interferes with messages
from the brain to the body. Symptoms of MS may include vision
problems, loss of balance, numbness, difficulty walking and paralysis.

About UCB

UCB (www.ucb-group.com) is a leading global biopharmaceutical
company dedicated to the research, development and commercialisation
of innovative pharmaceutical and biotechnology products in the fields
of central nervous system disorders, allergy/respiratory diseases,
immune and inflammatory disorders and oncology. UCB focuses on
securing a leading position in severe disease categories. Employing
over 8,500 people in over 40 countries, UCB achieved revenue of 2.5
billion euro in 2006. UCB is listed on the Euronext Brussels Exchange
and its worldwide headquarters are located in Brussels, Belgium.

About Biogen Idec

Biogen Idec creates new standards of care in therapeutic areas
with high unmet medical needs. Founded in 1978, Biogen Idec is a
global leader in the discovery, development, manufacturing, and
commercialization of innovative therapies. Patients in more than 90
countries benefit from Biogen Idec's significant products that address
diseases such as lymphoma, multiple sclerosis, and rheumatoid
arthritis. For product labeling, press releases and additional
information about the company, please visit www.biogenidec.com.

UCB and Biogen Idec Safe Harbor

This press release contains forward-looking statements regarding
the development of CDP323. Drug development involves a high degree of
risk. Only a small number of research and development programs result
in commercialization of a product. Factors which could cause actual
results to differ materially from UCB's and Biogen Idec's current
expectations include the risk that the companies may not be able to
demonstrate the safety and efficacy of CDP323 at each stage of the
clinical trial process; technical hurdles relating to the manufacture
of CDP323 may be encountered; applicable regulatory standards may not
be met or regulatory authorities may fail to approve CDP323; and other
unexpected hurdles may be encountered.

For more detailed information on the risks and uncertainties
associated with Biogen Idec's drug development activities, see the
section entitled "Risk Factors" in Biogen Idec's quarterly report on
Form 10-Q for the fiscal quarter ended March 31, 2007 which was filed
with the Securities and Exchange Commission, as well as other periodic
and current reports of Biogen Idec filed with the Securities and
Exchange Commission. Biogen Idec assumes no obligation to update any
forward-looking statements, whether as a result of new information,
future events or otherwise.