PHILADELPHIA, February 7, 2012 /PRNewswire/ -- Vyvanse(lisdexamfetamine dimesylate), an approvedtreatmentforAttention-Deficit/Hyperactivity Disorder ( ADHD)inpatientsages6 and above,is the first medicationbothproven to work and approvedformaintenance treatment in adults withADHD Shire plc (LSE: SHP, NASDAQ: SHPGY), the global specialty biopharmaceutical company, today announced that the US Food and Drug Administration (FDA) approved the prescription medication Vyvanse® (lisdexamfetamine dimesylate) Capsules, (CII) as a maintenance treatment for adults with ADHD. The approval is based on results from a randomized withdrawal study designed to evaluate the efficacy of Vyvanse in adults (aged 18 to 55 years) who were receiving treatment with Vyvanse for a minimum of 6 months prior to enrolling in the study. Significantly more patients treated with Vyvanse maintained ADHD symptom control compared with placebo as determined by the proportion of patients who met criteria for relapse of symptoms at end point during the six-week randomized double-blind withdrawal phase of the study (8.9% of Vyvanse-treated patients vs 75% for placebo). This new approval adds to the indication for Vyvanse as a treatment for ADHD in patients ages 6 and above. Vyvanse should be used as part of a total treatment program that may include counseling or other therapies. The physician who elects to use Vyvanse for extended periods should periodically reevaluate the long-term usefulness of the drug for the individual patient. In a randomized withdrawal design, patients who respond to a treatment are randomized to continue receiving that treatment or placebo. Utilizing the proportion of patients experiencing symptom relapse as a primary outcome, this type of study in patients with ADHD can be used to demonstrate long-term efficacy in lieu of conducting a long-term placebo-controlled, parallel-group study. The utility of this design is that the period of placebo exposure, with the potential for worsening of ADHD symptoms, is relatively short. "Data from this study and the resulting approval illustrate that Vyvanse can help adults with ADHD maintain symptom control. Vyvanse is the first medicine both proven to work and approved to maintain efficacy in adults with ADHD" said Jeffrey Jonas, MD, Senior Vice President of Research and Development for Shire's Specialty Pharmaceuticals and Regenerative Medicine businesses. "This underscores Shire's commitment to providing important advances in the treatment of individuals with ADHD by investing in innovative research in this area," added Dr. Jonas. Vyvanse is a Schedule II controlled substance. Stimulants, such as amphetamines and methylphenidates, are subject to misuse, abuse, addiction, and criminal diversion. Misuse of amphetamines may cause sudden death and serious cardiovascular adverse events.