Progression free survival and toxicity with dose variations of everolimus in metastatic hormone receptor positive breast cancer.

e12058Background: Everolimus is a sirolimus derivative that inhibits the mTOR (mammalian target of rapamycin) pathway. The BOLERO-2 trial showed improved progression free survival (PFS) with combined everolimus and exemestane versus exemestane alone in metastatic hormone receptor positive post-menopausal breast cancer patients. The initial dose of everolimus was 10mg and allowed for two dose reductions, 5mg daily and 5mg every other day. No data is available on PFS or toxicity for patients who were started, or dose reduced and maintained, on lower doses. We undertook a retrospective evaluation of PFS in patients with dose variations to determine if dose reductions adversely affect survival. Methods: Patients who were treated with the combination of everolimus and exemestane at Moffitt Cancer Center from April 26, 2012 - May 31, 2015 were obtained from our pharmacy database. A total of 138 patients met criteria consistent with BOLERO-2 patients. Chart review was performed to obtain data points. Results: PF...