for the treatment of Major Depressive Disorder in adult patients who have failed to achieve satisfactory improvement from one prior antidepressant medication at or above the minimal effective dose and duration in the current episode.
If you want to read the PDF of the full press release click here (beware, language geared to potential investors...).
In order to convince the manufacturer had to do an additional trial. If you want some more information on the development history read the excellent summary from the blog Brain Stimulant.