Joint FDA Advisory Committee Recommends Approval of TYSABRI(R) for the Treatment of Moderate to Severe Crohn's Disease

Elan Corporation, plc (NYSE: ELN) and Biogen Idec (NASDAQ: BIIB)
announced today that the Gastrointestinal Drugs Advisory Committee and
the Drug Safety and Risk Management Advisory Committee of the U.S.
Food and Drug Administration (FDA) voted 12 in favor to 3 opposed,
with 2 abstaining, to recommend approval of TYSABRI(R) (natalizumab)
as a treatment for moderate-to-severe Crohn's disease in patients who
have failed or cannot tolerate available therapies.

The recommendation is advisory to the FDA, and the agency is not
bound by this recommendation. Elan and Biogen Idec will continue to
work closely with the FDA in the weeks ahead with the goal of making
TYSABRI available for the treatment of appropriate patients with
Crohn's disease. Discussions with the FDA will include adapting the
existing TYSABRI risk management plan and addressing any other issues
raised during the Committees' deliberations on this new indication.

About TYSABRI(R) (natalizumab)

TYSABRI is a treatment approved for relapsing forms of multiple
sclerosis (MS) in the US and relapsing-remitting MS in the European
Union. According to data that have been published in the New England
Journal of Medicine, after two years, TYSABRI treatment led to a 68%
relative reduction (p less than 0.001) in the annualized relapse rate
compared to placebo and reduced the relative risk of disability
progression by 42-54% (p less than 0.001).

TYSABRI increases the risk of progressive multifocal
leukoencephalopathy (PML), an opportunistic viral infection of the
brain that usually leads to death or severe disability. Other serious
adverse events that have occurred in TYSABRI-treated patients included
hypersensitivity reactions (e.g., anaphylaxis), infections, depression
and gallstones. Serious opportunistic and other atypical infections
have been observed in TYSABRI-treated patients, some of whom were
receiving concurrent immunosuppressants. Herpes infections were
slightly more common in patients treated with TYSABRI. In MS trials,
the incidence and rate of other serious and common adverse events,
including the overall incidence and rate of infections, were balanced
between treatment groups. Common adverse events reported in
TYSABRI-treated patients include headache, fatigue, infusion
reactions, urinary tract infections, joint and limb pain, lower
respiratory infections, rash, gastroenteritis, abdominal discomfort,
vaginitis, and diarrhea.

TYSABRI is approved in the United States, European Union,
Switzerland, Canada, Australia and Israel. TYSABRI was discovered by
Elan and is co-developed with Biogen Idec.

For more information about TYSABRI please visit www.tysabri.com,
www.biogenidec.com or www.elan.com, or call 1-800-456-2255.

About Elan

Elan Corporation, plc is a neuroscience-based biotechnology
company committed to making a difference in the lives of patients and
their families by dedicating itself to bringing innovations in science
to fill significant unmet medical needs that continue to exist around
the world. Elan shares trade on the New York, London and Dublin Stock
Exchanges. For additional information about the company, please visit
www.elan.com.

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: http://www.biogenidec.com

Safe Harbor/Forward Looking Statements

This press release contains forward-looking statements regarding
TYSABRI. The commercial potential and regulatory path forward of
TYSABRI are subject to a number of risks and uncertainties. Factors
which could cause actual results to differ materially from the
companies' current expectations include the risk that concerns may
arise from additional data or analysis or that the companies may
encounter other unexpected delays or hurdles. There is also no
assurance that the companies will be able to obtain approval for
TYSABRI as a treatment for Crohn's disease. Drug development and
commercialization involves a high degree of risk. For more detailed
information on the risks and uncertainties associated with the
companies' drug development and other activities, see the periodic
reports that Biogen Idec and Elan have filed with the Securities and
Exchange Commission. The companies assume no obligation to update any
forward-looking statements, whether as a result of new information,
future events or otherwise.