Shire Receives New Paragraph IV Notice Letter From Watson for ADDERALL XR(R)

DUBLIN, Ireland and PHILADELPHIA, February 24, 2011 - Shire plc (LSE: SHP, NASDAQ: SHPGY), the global specialty
biopharmaceutical company, announces that its subsidiaries Shire LLC and
Shire Development Inc. (collectively "Shire") have received a new Paragraph
IV Notice Letter from Watson Laboratories, Inc. in Fort Lauderdale, Florida
("Watson") advising of the filing of an Abbreviated New Drug Application
("ANDA") for a generic version of all approved strengths of Shire's ADDERALL
XR(R) (mixed salts of a single-entity amphetamine product) dextroamphetamine
sulphate, dextroamphetamine saccharate, amphetamine aspartate monohydrate,
amphetamine sulphate capsules, CII.

The new ANDA that Watson filed is not covered under the existing
settlement agreements entered into in November 2007 between Shire and Watson
(the "Settlement Agreements"). The Settlement Agreements cover a different
ANDA and do not provide any license for Watson to sell the products covered
in Watson's new ANDA.

ADDERALL XR(R) is protected by the following FDA Orange Book listed
patents: U.S. Reissued Patent RE41,148, which is a reissue of U.S. Patent No.
6,605,300, and U.S. Patent No. 6,322,819, which has recently reissued as U.S.
Reissued Patent RE42,096.

Patent protection will expire in April 2019.

Shire is currently reviewing the details of Watson's Paragraph IV Notice
Letter which was directed to each of the Orange Book listed patents. Under
the Hatch-Waxman Act, Shire has 45 days from the receipt of the Notice Letter
to determine if it will file a patent infringement suit. If Shire brings suit
pursuant to the Hatch Waxman regulations, a stay of approval of up to
30-months will be imposed by the FDA on Watson's ANDA.

Shire submitted a Citizen Petition (CP) to the FDA in October 2005
requesting that the FDA impose stricter bioequivalence standards before
approving any ANDA for ADDERALL XR(R). The FDA responded that the CP raised
"complex issues" and has not resolved the matter. The FDA has not approved
any ANDA for ADDERALL XR(R).

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

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