This is a prospective, single arm trial in which patients with locally advanced or metastatic endocrine receptor positive and HER2 negative breast cancer refractory to non-steroidal aromatase inhibitors (NSAI) will receive Everolimus 10mg orally daily given in conjunction with exemestane 25mg orally daily until disease progression or treatment discontinuation for any other reasons. The main objectives are to evaluate if early metabolic response (MR) using FDG-PET/CT is associated with progression free survival (PFS) and overall survival (OS) in this population.