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