AstraZeneca and partner Targacept have suffered a clinical setback with the news that the latter's investigational attention-deficit hyperactivity disorder drug has failed in a mid-stage trial.

Targacept has announced top-line results from a Phase II trial of TC-5619 in non-smoker adults with ADHD that show the compound did not meet the primary efficacy outcome measure. TC-5619 was generally well tolerated, with no serious adverse events reported and no clinically significant difference between the TC-5619 dose group and the placebo dose group in discontinuations due to such events.

However, this is not necessarily the end of the road for the drug because in January, Targacept presented positive top-line results from a separate Phase II trial of TC-5619 in cognitive dysfunction in schizophrenia . The treatment is a highly-selective alpha7 neuronal nicotinic receptor modulator.

Donald deBethizy, Targacept’s chief executive, said that "while we did not see stimulant-like efficacy in this learning trial, the overall findings provide additional evidence that TC-5619 is active in a cognitively-impaired patient population, with the safety results adding to an impressive profile for a compound that has now been studied in more than 200 subjects".

He added that "coupled with positive outcomes from our prior Phase II study in patients with schizophrenia on measures of executive function, negative symptoms of schizophrenia and global change, we now have a foundation to guide future development of TC-5619".

Dr deBethizy said the company and AstraZeneca will continue to "pursue a strategy of using initial Phase II development to gain clinical insights that help identify the indications for which our compounds will be best suited for later-stage development”. A decision is expected in the second quarter.