Everolimus Beyond Progress for Patients Who Had Progress Under Everolimus and Exemestane

With continuation of endocrine treatment of breast cancer an adaptive upregulation of different signaling cascades including the PI3K/akt/mTOR pathway results in cell growth stimulation and results in resistance to endocrine therapies. One way to restore endocrine sensitivity is the inhibition of the mTOR pathway in combination with endocrine therapy leading to an increase in PFS compared with endocrine therapy alone. Guidelines recommend the sequential treatment with different endocrine therapies. It therefore appears reasonable to explore if sensitivity can be restored by changing the subsequent endocrine combination partner of Everolimus in case of failure of a combined endocrine-everolimus therapy.