REG-Elan Corporation PLC Data Presented at the 60th Annual Meeting of the American Academy of Neurology Offers Additional Support for Plasma Exchange as a Potential Tool to Accelerate TYSABRI(R) Removal

Data Presented at the 60th Annual Meeting of the American Academy of Neurology Offers Additional Support for Plasma Exchange as a Potential Tool to Accelerate TYSABRI(R) Removal

DUBLIN, Ireland--(Business Wire)--

Biogen Idec (NASDAQ: BIIB) and Elan Corporation, plc (NYSE: ELN) today announced
additional findings from the PLEX study which shows that plasma exchange
accelerates the removal of TYSABRI(R) (natalizumab) from blood serum in patients
and may help improve central nervous system immune response based on an in vitro
model. The data was presented today at the 60th Annual Meeting of the American
Academy of Neurology (AAN). Plasma exchange is one of several research efforts
the companies have underway to learn more about potential interventions or
treatments for progressive multifocal leukoencephalopathy (PML).

"The goal of these studies is to evaluate the value of plasma exchange in
patients who may develop PML. The data are encouraging as they show that removal
of TYSABRI through plasma exchange may be a potential intervention to rapidly
clear TYSABRI and restore immune function when clinically appropriate," said the
study's lead author, Bhupendra O. Khatri, MD, Medical Director of the Regional
MS Center, Aurora St. Luke's Medical Center, Milwaukee, WI.

PLEX is an open-label, single-arm, multicenter exploratory study involving 12
patients with relapsing-remitting multiple sclerosis (MS), designed to explore
whether plasma exchange could significantly reduce the concentration of TYSABRI
in blood serum and alpha 4-integrin receptor saturation. Plasma exchange is an
established method of removing large molecules from the body's blood
circulation. Based on the PLEX findings, plasma exchange was effective at
accelerating the normal decline of TYSABRI serum concentrations.

A sub-study of PLEX, also presented today at the meeting, evaluated the effect
of plasma exchange on the migration of certain immune cells, called leukocytes,
across an in vitro model of the blood-brain barrier. TYSABRI was shown to reduce
the migration of these cells across the blood-brain barrier. The results showed
that plasma exchange improved the ability of these cells to migrate across the
blood brain barrier, potentially reestablishing normal central nervous system
immune response.

Plasma exchange was generally well tolerated with no increase in MS disease
activity. There were no study discontinuations due to adverse events and all
patients returned to TYSABRI treatment without complications. While further
studies are being conducted, plasma exchange has been shown to hold potential as
an intervention in the setting of PML.

Abstracts from the larger PLEX study, "Plasma Exchange Accelerates the Decline
of Serum Natalizumab Concentration in Patients with Multiple Sclerosis: Results
of the Natalizumab PLEX Study" (Presentation #S22.005) and the sub-analysis,
"Plasma Exchange Augments Leukocyte Transmigration Across an In Vitro
Blood-Brain Barrier In Natalizumab-Treated Patients with Multiple Sclerosis"
(Presentation #S27.005) are available on-line at the AAN's website.

About TYSABRI

TYSABRI is a treatment approved for relapsing forms of MS in the United States
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<0.001) in the annualized relapse
rate compared to placebo and reduced the relative risk of disability progression
by 42-54% (p<0.001).

TYSABRI was recently approved to induce and maintain clinical response and
remission in adult patients with moderately to severely active Crohn's disease
(CD) with evidence of inflammation who have had an inadequate response to, or
are unable to tolerate, conventional CD therapies and inhibitors of TNF-alpha.

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)
and infections. 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 and CD clinical trials, the incidence and rate of
other serious adverse events, including serious infections, were similar in
patients receiving TYSABRI and those receiving placebo. Common adverse events
reported in TYSABRI-treated MS patients include headache, fatigue, infusion
reactions, urinary tract infections, joint and limb pain, and rash. Other common
adverse events reported in TYSABRI-treated CD patients include respiratory tract
infections and nausea. Clinically significant liver injury has been reported in
patients treated with TYSABRI in the post-marketing setting.

TYSABRI is approved in more than 30 countries including the United States and
many countries throughout the European Union, as well as Switzerland, Canada,
Australia, New Zealand and Israel.

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

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.

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.

Safe Harbor/Forward-Looking Statements

This press release contains forward-looking statements regarding TYSABRI and the
PLEX study. These statements are based on the companies' current beliefs and
expectations. The commercial potential of TYSABRI is 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 we may
be unable to adequately address concerns or questions raised by FDA or other
regulatory authorities, that concerns may arise from additional data, that the
incidence and/or risk of PML or other opportunistic infections in patients
treated with TYSABRI may be higher than observed in clinical trials, or that the
companies may encounter other unexpected hurdles. 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 and current
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.

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MEDIA CONTACTS:
Biogen Idec
Shannon Altimari, 617-914-6524
or
Elan
Jonathan Birt, 212-850-5664
or
Elizabeth Headon, +353 1 498 0300
or
INVESTOR CONTACTS:
Biogen Idec
Eric Hoffman, 617-679-2812
or
Elan
Chris Burns, + 353 1 709 4444 or 800-252-3526
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Elan Corporation PLC

Copyright Business Wire 2008