REG-Elan Corporation PLC Subset Data from Two Randomized Phase 3 Trials Show TYSABRI® Significantly Improves Health-Related Quality of Life for Crohn’s Disease Patients with Prior Exposure or Inadequate Response to Anti-TNFα

DUBLIN, Ireland--(Business Wire)--

Elan Corporation, plc (NYSE: ELN) and Biogen Idec (NASDAQ: BIIB) shared data
today that TYSABRI® (natalizumab) improved health related quality of life (QOL)
in Crohn`s Disease (CD) patients who had previously been exposed to or failed
anti-TNFα therapy versus placebo. These results were obtained from subset
analyses of the Phase 3 ENACT-2 (Evaluation of Natalizumab as Continuous
Therapy) and ENCORE (Efficacy of Natalizumab in Crohn`s Disease Response and
Remission) trials and were presented today at Digestive Disease Week in Chicago.

QOL was measured using the patient-reported, disease-specific Inflammatory Bowel
Disease Questionnaire (IBDQ), which measures bowel function, emotional function,
systemic function, and social function. The Short-form 36 (SF-36), a general
measure of QOL including physical function, bodily pain, general health, social
function, mental health and vitality, was also used. In the 12-week ENCORE
induction trial, patients receiving TYSABRI (n=89) who had failed previous
anti-TNFα therapy achieved statistically significant improvements compared with
those receiving placebo (n=83) on the total IBDQ scale and the two summary
scales of the SF-36, the Physical Component Summary and the Mental Component
Summary.

In the ENACT-2 maintenance trial, patients classified as responders to TYSABRI
and who had an inadequate response to anti-TNFα therapy (n=32) had total IBDQ
scores above 170, a level consistent with remission, throughout the length of
the trial. These levels were significantly higher than placebo (n=40) at all
measurements (P<0.05 at weeks 24, 36, 48, and 60). In addition, at week 60 of
therapy, there was no clinically meaningful difference (i.e. <5 points) between
patients receiving TYSABRI and the general population on seven of the eight
individual scales of the SF-36. While the ability to improve the QOL of patients
who have failed previous anti-TNFα therapy is important, a larger clinical
question is whether these improvements can be sustained during long-term
therapy.

Brian Feagan, M.D., of the Robarts Research Institute at the University of
Western Ontario, and first author of a manuscript published in the American
Journal of Gastrointerology1 detailing the effects of TYSABRI on the full sample
of patients in ENACT-2, said these data showed a similar impact. "In the more
difficult-to-treat subsets of patients studied here, TYSABRI helped patients
with moderate to severe CD achieve and maintain a considerably improved QOL as
measured by the IBDQ and the SF-36 as compared with placebo," Dr. Feagan said.

"TYSABRI is an important treatment option for patients with this debilitating
disease who have failed anti-TNFα therapies," stated Elan President Carlos V.
Paya, MD, PhD.

"Quality of life is an important measure of how CD patients feel in their
day-to-day lives," said Michael Panzara, MD, MPH, vice president, chief medical
officer of neurology, Biogen Idec.

1 Feagan BG, Sandborn WJ, Hass S, et al. (2007). Health-Related Quality of Life
During Natalizumab Maintenance Therapy for Crohn`s Disease. Am J Gastroenterol,
102:2737-2746. doi: 10.1111/j.1572-0241.2007.01508.x

About ENCORE and ENACT-2

Data from the ENCORE trial showed that TYSABRI induced response and remission
among patients with moderately to severely active CD, and objective evidence of
inflammation, as measured by elevated C-reactive protein.

After 12 weeks of therapy, 60% of TYSABRI-treated patients attained response,
compared to 44% of placebo treated patients, and 48% of patients showed a
response at both weeks 8 and 12, compared to 32% of placebo treated patients
(p<0.005 for both). Among the patients who had inadequate response to prior
treatment with inhibitors of TNFα, 38% achieved a response at weeks 8 and 12.

ENACT-2 presented maintenance data for an additional year of TYSABRI therapy
among patients with an initial response to TYSABRI, after 3 months in ENACT-1.
Of patients with response in ENACT-1, sustained response during ENACT-2 was seen
in 61% of patients treated with TYSABRI at every visit through an additional 6
months of therapy, compared to 29% for placebo. This treatment difference was
also sustained through 12 months of additional therapy (54% vs. 20%). Remission
was maintained at every visit with an additional 6 months or 12 months of
TYSABRI in 45% and 40% of patients, respectively, compared to 26% and 15% of
placebo treated patients (p<0.005 at 6 months). Among the patients that had
previously failed anti-TNFα therapy, response and remission was sustained at
every visit through an additional 6 months of TYSABRI in 52% and 30% of
patients, respectively. Given the requirement to discontinue chronic steroids,
among the subset of patients(n=65) on steroids and in whom a clinical response
was achieved, approximately two-thirds were able to discontinue steroids within
10 weeks of beginning to taper steroids. Although permitted in the clinical
trials, combination therapy with immunosuppressants is not recommended.

About Crohn's Disease (CD)

An estimated 500,000 people in the United States have CD, a chronic and
progressive inflammatory disease of the gastrointestinal tract, which commonly
affects both men and women. CD can have a devastating impact on the lifestyle of
patients, many of whom are young and active. Currently there is no medical or
surgical cure for CD. Many patients fail to respond to current therapies,
including biological therapies such as agents that inhibit tumor necrosis factor
alpha (TNFα). Due to this failure of current therapies in CD, therapies that
have alternate biological targets provide patients and physicians with
therapeutic options.

The disease usually causes diarrhea and cramping abdominal pain, often
associated with fever, and at times rectal bleeding. Loss of appetite and weight
loss also may occur. Complications include narrowing of the intestine,
obstruction, abscesses, and fistulas (abnormal channels connecting the intestine
and other organs, including the skin), and malnutrition. Most patients
eventually require surgery, which has both risks and potential short- and
long-term complications.

About TYSABRI®

TYSABRI is a treatment approved for relapsing forms of MS in the U.S. 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 percent relative reduction (p<0.001) in the annualized
relapse rate compared with placebo and reduced the relative risk of disability
progression by 42-54 percent (p<0.001).

In early 2008, TYSABRI was approved in the U.S. 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. According to the US full prescribing information, among patients
who responded to TYSABRI in a clinical trial, 54 percent sustained their
response through the one year visit compared to 20 percent of patients receiving
placebo, for a treatment difference of 34%.

TYSABRI increases the risk of progressive multifocal leukoencephalopathy (PML),
an opportunistic viral infection of the brain that usually leads to death or
severe disability. Cases of PML have been reported in patients taking TYSABRI
who were recently or concomitantly treated with immunomodulators or
immunosuppressants, as well as in patients receiving TYSABRI as monotherapy.
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 40 countries.

For more information about TYSABRI please visit www.tysabri.com,
ww.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 bringing
innovations in science to fill significant unmet medical needs. 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 www.biogenidec.com.

Safe Harbor/Forward-Looking Statements

This press release contains forward-looking statements regarding TYSABRI. 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 the 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, that the
companies may encounter other unexpected hurdles, or that new therapies for MS
with better efficacy or safety profiles or more convenient methods of
administration are introduced into the market. 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 Elan has 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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Investors:
Elan
Chris Burns, 800-252-3526
David Marshall, 353-1-709-4444
or
Biogen Idec
Eric Hoffman, 617-679-2812
Media:
Elan
Miriam Mason, 650-278-7113 (onsite)
Mary Stutts, 650-794-4403
or
Biogen Idec
Shannon Altimari, 617-914-6524

Elan Corporation PLC

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