Shire AG, the global specialty biopharmaceutical company, has presented results of the Phase 3 study which demonstrated the long-term maintenance of efficacy of lisdexamfetamine dimesylate (LDX) in children and adolescents aged 6 to 17 years with attention-deficit/hyperactivity disorder (ADHD).

Children and adolescents diagnosed with ADHD were treated with LDX (30, 50 or 70mg/day) during an open-label period (comprising dose optimisation, maintenance, and fixed dose periods) of at least 26 weeks before entering a 6-week double-blind randomised withdrawal period, where subjects received either LDX or placebo. Results showed maintenance of efficacy in children and adolescents who continued to receive LDX, as demonstrated by a significantly lower proportion of ADHD treatment failures (13.5%) in this group, compared with placebo (65.8%); and the majority of placebo-treated subjects who met protocol-defined ADHD symptom relapse criteria did so within 2 weeks following randomisation. The overall nature, pattern, and incidence of treatment-emergent adverse events (TEAEs) were also consistent with those reported in other LDX studies in ADHD.

“These are important results which demonstrate the maintenance of efficacy in children and adolescents. Long-term maintenance therapy plays an important role in the treatment of ADHD. There are however, few long-term controlled studies in children and adolescents assessing the maintenance of efficacy and long-term safety of stimulant medication versus placebo,” said Dr. Jeffrey Jonas, Senior Vice President of Research and Development for Shire’s Specialty Pharmaceuticals and Regenerative Medicine businesses. “The positive results presented today complement existing data and we look forward to making LDX available as a treatment option for ADHD in children and adolescents in Europe.”

This study is a critical element of the European submission package. A European MAA (Marketing Authorisation Application) for LDX was accepted for review in January 2012.

Relapse or treatment failure in this International study was determined to have occurred when a subject has both a ≥50% increase (or worsening) in ADHD-Rating Scale-IV (ADHD-RS-IV) total score, and a ≥2-point increase (or worsening) in Clinical Global Impressions–Severity of Illness (CGI-S) rating scale score, at any double-blind visit relative to the respective scores at randomisation.

The study was conducted at 37 sites in Europe (n=236, or 85% of subjects) and 4 sites in the US (n=40, or 15% of subjects). The results are consistent with a similar randomised withdrawal design (RWD) study in adults in the US.

This study was originally designed to evaluate the long-term efficacy and safety of LDX for the treatment of ADHD in children and adolescents aged 6 to 17, and as an extension to the European Phase 3 study of the efficacy and safety of LDX in this population.

Further results on the study will be published soon.

Date: May 23, 2012
Source: Shire AG