INTUNIV(TM) - Shire Files Suit Against Impax and Watson

DUBLIN and PHILADELPHIA, December 3, 2010 - Shire plc (LSE: SHP, NASDAQ: SHPGY), the global specialty
biopharmaceutical company, announces that its subsidiary Shire LLC has filed
a lawsuit in the U.S. District Court for the Northern District of California
against Impax Laboratories, Inc. ("Impax") and Watson Pharmaceuticals, Inc.,
Watson Laboratories, Inc.-Florida, Watson Pharma, Inc and ANDA, Inc.
(collectively "Watson") for the infringement of U.S. Patent Nos. 5,854,290
(the '290 patent), 6,287,599 (the '599 patent), and 6,811,794 (the '794
patent).

The lawsuit results from Abbreviated New Drug Applications (ANDAs) filed
by Impax and Watson for generic versions of 4 mg guanfacine hydrochloride
extended release tablets, INTUNIV(TM), which seek to market such generic
products before the expiration of the '290, '599, and '794 patents. The
regulatory exclusivity period for INTUNIV(TM) runs through September 2, 2012.

Notes to editors

SHIRE PLC

Shire's strategic goal is to become the leading specialty
biopharmaceutical company that focuses on meeting the needs of the specialist
physician. Shire focuses its business on attention deficit hyperactivity
disorder (ADHD), human genetic therapies (HGT) and gastrointestinal (GI)
diseases as well as opportunities in other therapeutic areas to the extent
they arise through acquisitions. Shire's in-licensing, merger and acquisition
efforts are focused on products in specialist markets with strong
intellectual property protection and global rights. Shire believes that a
carefully selected and balanced portfolio of products with strategically
aligned and relatively small-scale sales forces will deliver strong results.

For further information on Shire, please visit the Company's website:
www.shire.com.

"SAFE HARBOR" STATEMENT UNDER THE PRIVATE SECURITIES LITIGATION REFORM
ACT OF 1995

Statements included herein that are not historical facts are
forward-looking statements. Such forward-looking statements involve a number
of risks and uncertainties and are subject to change at any time. In the
event such risks or uncertainties materialize, the Company's results could be
materially adversely affected. The risks and uncertainties include, but are
not limited to, risks associated with: the inherent uncertainty of research,
development, approval, reimbursement, manufacturing and commercialization of
the Company's Specialty Pharmaceutical and Human Genetic Therapies products,
as well as the ability to secure and integrate new products for
commercialization and/or development; government regulation of the Company's
products; the Company's ability to manufacture its products in sufficient
quantities to meet demand; the impact of competitive therapies on the
Company's products; the Company's ability to register, maintain and enforce
patents and other intellectual property rights relating to its products; the
Company's ability to obtain and maintain government and other third-party
reimbursement for its products; and other risks and uncertainties detailed
from time to time in the Company's filings with the Securities and Exchange
Commission.

For further information please contact:

    Investor Relations  Eric Rojas (erojas@shire.com)       +1-781-482-0999

    Media               Jessica Mann (jmann@shire.com)     +44-1256-894-280
                        Matthew Cabrey (mcabrey@shire.com)  +1-484-595-8248

Investor, Eric Rojas (erojas at shire.com), +1-781-482-0999, Relations, Media, Jessica Mann, (jmann at shire.com), +44-1256-894-280, Matthew Cabrey (mcabrey at shire.com) +1-484-595-8248