The invention relates to 6-oxo-6,7-dihydro-5H-dibenzo[b,d]azepin-7-yl derivatives of formula I ##STR00001## wherein R.sup.1, R.sup.2 and R.sup.3 are as defined herein. The compounds are .gamma.-secretase inhibitors useful in the treatment of Alzheimer's disease or common cancer, including, but not limited to, cervical carcinomas and breast carcinomas and malignancies of the hematopoietic system.