Shire's ADHD drug impresses in Phase III trial

UK-based drugmaker Shire says that data from a Phase III trial of its drug SPD503 (guanfacine extended release), administered as a once-daily monotherapy, significantly improved symptoms of attention-deficit hyperactivity disorder in children aged six to 17. The findings, which were presented at the US Psychiatric and Mental Health Congress on November 16, were accompanied by the results of two additional assessments of the agent that demonstrated its favorable pharmacokinetic profile.

In the Phase III study, 345 subjects were randomized to receive 2mg, 3mg or 4mg daily doses of the drug for a period of 11 weeks (a two-week screening section, followed by a seven-day washout period to allow for discontinuation of current medication and an eight-week treatment phase). Efficacy was assessed using the standard 18 point ADHD rating scale, which measures hyperactivity, impulsivity and inattention.

The results showed that treatment produced an average 16.7 point symptom reduction, compared with 8.9 in the placebo group. The firm added that investigators had observed such improvement as early as two weeks into the study, with significant benefit in all the dosage groups occurring at week three. In addition, significance was also seen in all secondary measures examined during the study.