Attention Deficit Hyperactivity Disorder (ADHD) is a neurobiological 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.
Approximately 7.8 percent of all school-age children, or about 4.4 million U.S. children aged 4 to 17 years, have been diagnosed with ADHD at some point in their lives, according to the U.S. Centers for Disease Control and Prevention (CDC).
Shire plc announced the results of a phase III trial which demonstrated that adults with ADHD experienced significant improvements in ADHD symptom control within one week of treatment with VYVANSE (lisdexamfetamine dimesylate), the first prodrug stimulant.
“Adults with ADHD may experience significant impairments in their ability to focus, and organize and complete tasks, which could affect their work, family life and personal relationships,” said Lenard A. Adler, M.D., lead researcher in this study and director of the Adult ADHD Program at New York University School of Medicine and author of Scattered Minds: Help and Hope for Adults with ADHD. “The results of this study demonstrated that VYVANSE significantly improved the core symptoms of ADHD in adult study patients.”
Results of Phase III Trial
In this double-blind, placebo-controlled, four-week study with dose escalations in 414 adults aged 18 to 55 years, treatment with VYVANSE at all doses studied (30 mg, 50 mg, 70 mg) was significantly more effective than placebo and improvements were observed in the first week of the study.
All doses of VYVANSE showed significant improvements in the average change in ADHD Rating Scale (ADHD-RS-IV) scores, as measured from the study’s start to end, the primary endpoint of this study. ADHD-RS-IV is a standardized, validated test for assessing symptoms of ADHD and for assessing their response to treatment. The scale, which contains 18 items, is based on the ADHD diagnostic criteria as defined in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision®, a publication of the American Psychiatric Association.
VYVANSE provided a significant reduction in ADHD-RS-IV scores starting at week one that were observed throughout the full treatment period. At endpoint, VYVANSE provided a significant reduction in ADHD-RS-IV scores ranging from 16.2 to 18.6 points.
Investigators also measured the efficacy of VYVANSE with the Clinical Global Impressions-Improvement (CGI-I) scale, a standard assessment used to rate the severity of a patient’s illness and improvement over time. The study found that the percentage of subjects taking VYVANSE rated improved on the CGI-I scale ranged from 57 to 61 percent across all doses and was significantly greater than placebo.
The study showed there were no statistically significant differences among the groups for total score of Pittsburgh Sleep Quality Index (PSQI) at endpoint with all groups showing a slight decrease in the PSQI total score at endpoint. The PSQI is a self-rated questionnaire that assesses sleep quality and disturbances over a one-month time interval.
Adverse events reported in this study were generally mild to moderate and included dry mouth (26 percent), decreased appetite (27 percent) and insomnia (19 percent).
VYVANSE is a therapeutically inactive prodrug, in which d-amphetamine is covalently bonded to l-lysine, and after oral ingestion it is converted to pharmacologically active d-amphetamine. The pharmacokinetic profile of VYVANSE is inherent to its chemical prodrug nature and alterations in gastric pH and gastrointestinal motility do not affect its absorption.
A supplemental New Drug Application (sNDA) for VYVANSE for the treatment of ADHD in adults is currently under review by the U.S. Food and Drug Administration (FDA). VYVANSE is currently approved in the United States for the treatment of ADHD in children aged 6 to 12 years.