Targacept plans to advance TC-5214, one of two enantiomers of mecamylamine hydrochloride, into clinical development as an augmentation therapy for patients who are inadequate responders to first-line antidepressant treatments. Targacept expects to initiate a Phase I trial of TC-5214 in the first quarter of 2008 and to initiate Phase II development soon thereafter. However, the company has no current plans to conduct further clinical development of mecamylamine.
Mecamylamine hydrochloride is a racemic compound comprised of two mirror image halves known as the S+ and R- enantiomers. TC-5214 is the S+ enantiomer of mecamylamine. In a Phase II trial in patients who did not respond adequately to first-line treatment with citalopram hydrobromide that Targacept completed in 2006, patients whose citalopram regimen was augmented with mecamylamine showed greater improvement on symptoms of depression and irritability than patients who received citalopram and a placebo.
Targacept said that the findings suggest that TC-5214 has potential as an augmentation treatment for major depression.