News Release

Shire presents new scientific data on ADHD treatments at National Psychiatric Scientific Meeting

Peer-Reviewed Publication

Porter Novelli

PHILADELPHIA – May 13, 2009 – Shire plc (LSE: SHP, NASDAQ: SHPGY), the global specialty biopharmaceutical company, today announced that it will present key scientific data on its Attention Deficit Hyperactivity Disorder (ADHD) treatments lisdexamfetamine dimesylate (CII) and investigational non-scheduled guanfacine extended release, at a national scientific meeting of psychiatrists to be held May 16 -21 in San Francisco, CA.

"Shire is committed to the advancement of ADHD treatment research and eager to present results from a spectrum of studies," said Jeffrey Jonas, MD, Senior Vice President of Research & Development for the Specialty Pharmaceuticals business at Shire. "We believe the lisdexamfetamine dimesylate and guanfacine extended release study findings to be presented will contribute greatly to the growing body of research and development for physicians in the field of ADHD."

A summary of the key scientific presentations is provided below. Information about these data presentations mentioned in this release is embargoed until the respective presentation sessions have taken place at the meeting.

Lisdexamfetamine Dimesylate
May 18, 2009; 12:30 PM to 2:00 PM PDT / 3:30 PM to 5 PM EDT
Pharmacokinetics of Intranasal Versus Oral Administration of Lisdexamfetamine Dimesylate in Healthy Adults
Poster Presentation #NR2-027

May 18, 2009; 12:30 PM to 2:00 PM PDT / 3:30 PM to 5 PM EDT
Duration of Effects of Lisdexamfetamine Dimesylate on Behavior of Children With Attention-Deficit/Hyperactivity Disorder in Naturalistic Settings
Poster Presentation # NR2-029

May 18, 2009; 12:30 PM to 2:00 PM PDT / 3:30 PM to 5 PM EDT
Patient Experience and Satisfaction with Lisdexamfetamine Dimesylate in Adults With ADHD
Poster Presentation #NR2-020

May 18, 2009; 12:30 PM to 2:00 PM PDT / 3:30 PM to 5 PM EDT
Response and Symptomatic Remission in a Long-Term Trial of Lisdexamfetamine Dimesylate in Adults with Attention-Deficit/Hyperactivity Disorder
Poster Presentation #NR2-054

May 18, 2009; 12:30 PM to 2:00 PM PDT / 3:30 PM to 5 PM EDT
Improvement in Emotional Expression in Children with Attention-Deficit/Hyperactivity Disorder Treated with 20 to 70 mg/day Lisdexamfetamine Dimesylate
Poster Presentation #NR2-019

May 18, 2009; 12:30 PM to 2:00 PM PDT / 3:30 PM to 5 PM EDT
Improvement in Executive Function in Children with Attention-Deficit/Hyperactivity Disorder Treated With 20 to 70 mg/Day Lisdexamfetamine Dimesylate
Poster Presentation #NR2-051

May 18, 2009; 12:30 PM to 2:00 PM PDT / 3:30 PM to 5 PM EDT
Changes in Emotional Expression Related to Medication Used to Treat Attention-Deficit/Hyperactivity Disorder
Poster Presentation #NR2-038

Guanfacine Extended Release
May 18, 2009; 12:30 PM to 2:00 PM PDT / 3:30 PM to 5 PM EDT
Effects of Guanfacine Extended Release on Secondary Measures in Children With Attention-Deficit/Hyperactivity Disorder and Oppositional Symptoms
Poster Presentation #NR2-060

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For further information please contact:

Porter Novelli for Shire:

Mindy Huber
Mindy.Huber@porternovelli.com
212-601-8330
917-653-6134 (on site at the meeting)

Debra Gemme
Debra.Gemme@porternovelli.com
212-601-88342
703-298-4030 (on site at the meeting)

About VYVANSE

Vyvanse is indicated for the treatment of ADHD. Efficacy based on two controlled trials in children aged 6 to 12 and one controlled trial in adults.

Vyvanse should not be taken by patients who have advanced arteriosclerosis; symptomatic cardiovascular disease; moderate to severe hypertension; hyperthyroidism; known hypersensitivity or idiosyncrasy to sympathomimetic amines; agitated states; glaucoma; a history of drug abuse; or during or within 14 days after treatment with monoamine oxidase inhibitors (MAOIs).

Sudden death has been reported in association with CNS stimulant treatment at usual doses in children and adolescents with structural cardiac abnormalities or other serious heart problems. Sudden death, stroke, and myocardial infarction have been reported in adults taking stimulant drugs at usual doses in ADHD. Physicians should take a careful patient history, including family history, and physical exam, to assess the presence of cardiac disease. Patients who report symptoms of cardiac disease such as exertional chest pain and unexplained syncope should be promptly evaluated. Use with caution in patients whose underlying medical condition might be affected by increases in blood pressure or heart rate.

New psychosis, mania, aggression, growth suppression, and visual disturbances have been associated with the use of stimulants. Use with caution in patients with a history of psychosis, seizures or EEG abnormalities, bipolar disorder, or depression. Growth should be monitored in children during treatment with stimulants, and patients who are not growing (gaining height or weight) as expected may need to have their treatment interrupted.

Amphetamines have a high potential for abuse. Administration of amphetamines for prolonged periods of time may lead to drug dependence. Particular attention should be paid to the possibility of subjects obtaining amphetamines for non-therapeutic uses or distribution to others and the drugs should be prescribed or dispensed sparingly. Misuse of amphetamine may cause sudden death and serious cardiovascular adverse events.

The most common adverse events reported in clinical studies of Vyvanse were: pediatric – decreased appetite, insomnia, abdominal pain, and irritability; adult – decreased appetite, insomnia, and dry mouth.

About Guanfacine Extended Release

Guanfacine Extended Release (GXR) is currently being studied as a once-daily, extended release formulation of guanfacine designed to provide steady delivery of drug throughout the day. GXR is pending FDA approval for the treatment of ADHD in children and adolescents. In clinical trials, GXR demonstrated significant reduction in ADHD symptoms. GXR is not a controlled substance and has no known mechanism for abuse or dependence.

Guanfacine, the active ingredient in GXR, is thought to work directly by binding selectively to alpha-2A adrenergic receptors located in the prefrontal cortex. The prefrontal cortex is an area of the brain associated with working memory, behavioral inhibition, regulation of attention, distractibility, and impulsivity. Although the mechanism of action of guanfacine in the treatment of ADHD is not fully understood, preclinical research suggests this selective alpha-2A agonist strengthens working memory and prefrontal cortex neuronal firing. This research supports the use of guanfacine for the treatment of ADHD.

In pivotal clinical trials, safety data showed that adverse events reported by participants using GXR were generally mild to moderate in severity, with the most common side effects being sedative in nature. Sedation-related, treatment-emergent adverse events were among the most common and were usually transient and mild or moderate in severity. Treatment-related adverse events greater than 10 percent included somnolence (32 percent), headache (26 percent), fatigue (18 percent), upper abdominal pain (14 percent) and sedation (13 percent). Syncope occurred in approximately 1 percent of pediatric patients in the clinical program. The majority of these cases occurred in the long-term, open label studies. Small to modest changes in blood pressure, pulse rate, and ECG parameters were observed.

About ADHD

ADHD is one of the most common psychiatric disorders in children and adolescents. Worldwide prevalence of ADHD is estimated at 5.3 percent (with large variability), according to a comprehensive systematic review of this topic published in 2007 in the American Journal of Psychiatry. In the United States, approximately 7.8 percent of all school-aged children, or about 4.4 million children aged 4 to 17 years, have been diagnosed with ADHD at some point in their lives, according to the Centers for Disease Control and Prevention (CDC). The disorder is also estimated to affect 4.4 percent of US adults aged 18-44 based on results from the National Comorbidity Survey Replication. When this percentage is extrapolated to the full US population aged 18 and over, approximately 9.8 million adults are believed to have ADHD.

ADHD is a psychiatric behavioral disorder that manifests as a persistent pattern of inattention and/or hyperactivity-impulsivity that is more frequent and severe than is typically observed in individuals at a comparable level of development. The specific etiology of ADHD is unknown and there is no single diagnostic test for this syndrome. Adequate diagnosis requires the use of medical and special psychological, educational and social resources, utilizing diagnostic criteria such as Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV-TR) or International Classification of Diseases 10 (ICD-10).

Although there is no "cure" for ADHD, there are accepted treatments that specifically target its symptoms. Standard treatments include educational approaches, psychological, or behavioral modification, and medication.

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.

THE "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.


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