Clinically non-functioning pituitary adenomas (CNFAs), the subtype of pituitary adenomas that does not appear to secrete biologically active hormone nor to have a characteristic clinical phenotype, are the most common type of pituitary macroadenoma at diagnosis. There is currently no option for medical therapy of CNFA, in general, or specifically of silent corticotroph tumors. Silent corticotroph tumors can range from being completely asymptomatic to becoming large and causing significant hypothalamic/pituitary dysfunction and visual symptoms, and most data support that this type of tumor has a more aggressive phenotype. Current therapy consists primarily of surgical removal of the tumor and for recurrent or residual tumors, repeated surgery and/or radiotherapy. In very aggressive tumors, chemotherapy has been tried with some success. Therefore, a need exists for a medical therapeutic option for the treatment of this tumor type. This project assesses this clinical need.