Shire Pharmaceuticals yesterday presented two-year data showing its top-selling, once-daily pill to treat attention deficit hyperactivity disorder, Adderall XR (amphetamine salts), resulted in long-term symptom control in adult patients.

The open-label study enrolled 221 patients and showed that all maintained a significant reduction in their symptoms over the two-year period, although those who had received Adderall XR for the first time demonstrated the most improvement at the end of the study period, says Shire, versus those who had continually received Adderall XR and those whose treatment was interrupted. All participants, with an average age of 40, had a history of ADHD from before age seven, although many had not been diagnosed until adulthood.

Shire was approved for use in the US adult population last year [[12/08/04b]], becoming the first stimulant therapy of its kind to win such a nod. Eli Lilly’s non-stimulant offering Strattera (atomoxetine) had previously been granted an OK in both adults and paediatric patients [[15/01/03d]].

Adderall XR is one of Shire's top selling drugs, bringing in third quarter sales of some $166 million dollars - up 18% [[04/11/05f]]. However, it is currently facing generic threats from a number of companies and Shire has already filed lawsuit against Barr and Impax, with the cases set to go to court in January and February 2006 respectively [[20/07/05g]].