The efficacy and safety analysis of the treatments of everolimus and exemestane combination in 101 metastatic breast cancer patients: Real-life experience from Turkey

Background: Endocrine treatment and chemotherapy are a treatment options for patients with hormone receptor (HR) positive and HER2-negative metastatic breast cancer (MBC). However, response to first-line hormone treatment could not obtained in all patients, and even patients who havea response will eventually relapse. After disease progression, second-line hormonal treatmentoptions are used sequentially. Everolimus with exemestane has demonstrated promising activity in patients with HR-positive HER2-negative endocrine-resistant MBC with respect to the results of the BOLERO-2 study. In the present study, we aimed to evaluate the efficacy and safety of this combination in the real-life clinical setting for the unselected population in Turkey. Material and Methods: One hundred and one patients with HR-positive HER-2 negative MBC progressing after prior endocrine treatment who were treated with everolimus with exemestane were retrospectively analyzed. The tolerability and efficacy of this combination were evaluated in the unselected Turkish patients. Results: Among 101 patients, 45% of patients had visceral and %50 patients had only bone metastasis. Everolimus with exemestane treatment was administered as a second-line in 21.3% of patients, third-line in 40.4% and forth-line and later in 38.2%. The objective response rate was 24.7% (CR+PR) and stable disease was obtained in 37.7% of patients. At the median follow-up time of 13.5 months, the median progression-free survival (PFS) time and 1-year PFS were 13.8 months and 57.2%, while the median overall survival (OS) interval and 1-year OS were 40 months and 85%. The median treatment duration was 8.3 and 6.5 months for exemestane and everolimus, respectively. The most frequent reason for discontinuation of treatment were disease progression (39%). Moreover, the most common advers events (AE) causing permanent discontinuation were stomatitis (3%) and pneumonitis (3%). A total of 81 % of patients experienced at least one AE of any grade, 25% of patients at least one grade 3 or 4 AE. Due to AEs, everolimus dosage was reduced to 5 mg in 16 (15.8%) of patients. Conclusions: Our findings confirmed that the combination of everolimus with exemestane was the safe and effective treatment options for patients with HR-positive HER-2 negative MBC after second or later lines treatments