Forest Laboratories’ application to market its Lexapro (excitalopram) antidepressant as a treatment for social anxiety disorder has been knocked back by the US Food and Drug Administration, the company has revealed.

Although the firm said that the FDA had indicated that data from one of the two required pivotal studies of the drug did support the application, it said the agency had questioned the reliability of patient data at one study centre. Once these data were eliminated, the trial failed to meet overall statistical significance.

Forest says that it is reviewing the FDA’s analysis and will determine the appropriate next steps to address the non-approvable letter in the coming months, which may include additional discussions with the FDA pertaining to data from the excluded center or conducting an additional pivotal study.

Lexapro is indicated in the US for the initial and maintenance treatment of major depressive disorder and for generalised anxiety disorder in adults [[23/08/02d]], [[19/12/03e]]. Earlier this month, the FDA knocked back an application to market the drug in the treatment of panic disorder [[02/03/05g]].