Everolimus plus endocrine therapy for postmenopausal women with estrogen receptor-positive, human epidermal growth factor receptor 2-negative advanced breast cancer: A clinical trial

• Main Authors: Melanie Royce, Thomas Bachelot, Cristian Villanueva, Mustafa Özgüroglu, Sergio J. Azevedo, Felipe Melo Cruz, Marc Debled, Roberto Hegg, Tatsuya Toyama, Carla Falkson, Joon Jeong, Vichien Srimuninnimit, William J. Gradishar, Christina Arce, Antonia Ridolfi, Chinjune Lin, Fatima Cardoso
• Other Authors: Champalimaud Foundation
• Format: Article
• Published: 2019
• Subjects: Biochemistry, Genetics and Molecular Biology; Medicine
• Online Access: https://repository.li.mahidol.ac.th/handle/123456789/45128
• Institution: Mahidol University

© 2018 American Medical Association. IMPORTANCE Cotargeting the mammalian target of rapamycin pathway and estrogen receptor may prevent or delay endocrine resistance in patients receiving first-line treatment for advanced breast cancer. OBJECTIVE To investigate the combination of everolimus plus endocrine therapy in first-line and second-line treatment settings for postmenopausal women with estrogen receptor-positive, human epidermal growth receptor 2-negative advanced breast cancer. DESIGN, SETTING, AND PARTICIPANTS In the multicenter, open-label, single-arm, phase 2 BOLERO-4 (Breast Cancer Trials of Oral Everolimus) clinical trial, 245 patients were screened for eligibility; 202 were enrolled between March 7, 2013, and December 17, 2014. A median follow-up of 29.5 months had been achieved by the data cutoff date (December 17, 2016). INTERVENTIONS Patients received first-line treatment with everolimus, 10mg/d, plus letrozole, 2.5mg/d. Second-line treatment with everolimus, 10mg/d, plus exemestane, 25 mg/d, was offered at the investigator's discretion upon initial disease progression. MAIN OUTCOMES AND MEASURES The primary end pointwas investigator-assessed progression-free survival in the first-line setting per Response Evaluation Criteria in Solid Tumors, version 1.0. Safety was assessed in patients who received at least 1 dose of study medication and at least 1 postbaseline safety assessment. RESULTS A total of 202 women treated in the first-line setting had a median age of 64.0 years (interquartile range, 58.0-70.0 years) with metastatic (194 [96.0%]) or locally advanced (8 [4.0%]) breast cancer. Median progression-free survival was 22.0 months (95%CI, 18.1-25.1 months) with everolimus and letrozole. Median overall survival was not reached; 24-month estimated overall survival rate was 78.7%(95%CI, 72.1%-83.9%). Fifty patients started second-line treatment; median progression-free survival was 3.7 months (95%CI, 1.9-7.4 months). No new safety signals were observed. In the first-line setting, the most common all-grade adverse event was stomatitis (139 [68.8%]); the most common grade 3 to 4 adverse event was anemia (21 [10.4%]). In the second-line setting, the most common adverse events were stomatitis and decreased weight (10 [20.0%] each); the most common grade 3 to 4 adverse event was hypertension (5 [10.0%]). There were 50 (24.8%) deaths overall during the study; 40 were due to study indication (breast cancer). CONCLUSIONS AND RELEVANCE The results of this trial add to the existing body of evidence suggesting that everolimus plus endocrine therapy is a good first-line treatment option for postmenopausal women with estrogen receptor-positive, human epidermal growth factor receptor 2-negative advanced breast cancer.