PHILADELPHIA – October 22, 2009 – Shire plc (LSE: SHP, NASDAQ: SHPGY), the global specialty biopharmaceutical company, announced new data about the pharmacokinetics of its Attention-Deficit/Hyperactivity Disorder (ADHD) medication, Vyvanse® (lisdexamfetamine dimesylate) Capsules CII, which showed that Vyvanse provided similar concentrations of its active medication in the blood when administered either intranasally or when administered orally. Specifically, the overall rate and extent of exposure to d-amphetamine, the active medication in Vyvanse, was similar in healthy adults whether they received the drug as a solution through the nose or orally as a capsule. These findings, which were recently presented at a major psychiatric meeting, reflect the ongoing efforts of Shire to further understand the abuse potential of Vyvanse.
"This research is important because the route of administration of a drug may affect the rate and extent of absorption, which in turn may affect the risk of abuse. However, in this study, absorption of Vyvanse through the nose did not result in a rapid rise in d-amphetamine levels," said Patrick Martin, MD, Vice President, Global Clinical Pharmacology and Pharmacokinetics at Shire. "In this study, exposure to d-amphetamine did not differ when Vyvanse was administered orally or intranasally. While the results of this study are important, it is not accurate to say or imply that Vyvanse cannot be abused."
Vyvanse is indicated for oral administration only, and should not be administered intranasally.
About VyvanseVyvanse, which is approved to treat ADHD in children aged 6 to 12 years and in adults, 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 conversion of Vyvanse to d-amphetamine is not affected by gastrointestinal pH and is unlikely to be affected by alterations in GI transit times. ADHD stimulant products are classified as schedule II controlled substances because a high potential for abuse exists.
About the StudyThis open-label, two-period, crossover study compared the pharmacokinetics of d-amphetamine, the active medication derived from Vyvanse, in 18 healthy men after single administration through nasal and oral routes. The primary objectives of the study were to determine whether Vyvanse is absorbed after intranasal delivery and to assess the extent of absorption and conversion tod-amphetamine, specifically whether administration through the nose would alter the rate and extent of absorption. A secondary study objective was to evaluate the safety of Vyvanse administered as a single oral dose and a single intranasal dose.
In the study, investigators randomly assigned participants to receive a single nasal or oral dose of Vyvanse 50 mg, then, at least seven days later, the subjects received the opposite regimen. Results showed that the rate and extent of d-amphetamine exposure were similar in the healthy participants who received a single 50-mg dose of Vyvanse either through the nose via a solution formulation or orally in capsule form. Specifically, the median time to maximum plasma concentration of d-amphetamine was five hours after oral administration of Vyvanse and four hours after intranasal administration of Vyvanse. Maximum plasma concentration for intranasal administration and oral administration of Vyvanse were similar (35.9 ng/mL versus 37.6 ng/mL, respectively).
In this study, treatment-emergent adverse events were mild to moderate in severity and consistent with known effects of amphetamine. The most common adverse events with an incidence greater than 5 percent among subjects administered Vyvanse by intranasal administration were: tachycardia (two of 18 subjects), dry mouth (two of 18 subjects), and feeling jittery (two of 18 subjects), and for oral administration: anorexia (four of 18 subjects). Adverse events were more common after intranasal administration, reported by 38.9 percent of participants (seven of 18), compared with 27.8 percent of participants (five of 18) after oral administration.
Vyvanse, which was introduced in the United States in July 2007 for the treatment of ADHD in children aged 6 to 12 years and approved in April 2008 to treat ADHD in adults, is currently available in six dosage strengths of 20 mg, 30 mg, 40 mg, 50 mg, 60 mg, and 70 mg.
Source: Porter Novelli