Everolimus plus endocrine therapy may be an effective first-line combination for postmenopausal women with advanced, estrogen receptor–positive (ER+), HER2-negative (HER2-) breast cancer, according to a study published in JAMA Oncology.1

Evidence from previous studies suggests that everolimus plus endocrine therapy (eg, tamoxifen, fulvestrant, letrozole, and exemestane) improves progression-free survival (PFS) among patients with hormone receptor–positive, HER2- breast cancer.

For the open label phase 2 BOLERO-4 study (ClinicalTrials.gov Identifier: NCT01698918), researchers treated 202 postmenopausal women with ER+, HER2- breast cancer with first-line oral everolimus 10 mg plus letrozole 2.5 mg daily and, in the case of disease progression, second-line therapy with everolimus 10 mg plus exemestane 25 mg daily. Ninety-six percent of patients had metastatic disease and 4% had locally advanced breast cancer; the median age was 64 years.

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After a median follow-up of 29.5 months, the median PFS was 22 months (95% CI, 18.1-25.1) for patients treated with first-line everolimus and letrozole. The median overall survival (OS) was not evaluable, though the estimated 2-year OS rate was 78.7% (95% CI, 72.1%-83.9%).

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Of the 50 patients who received second-line therapy, the median PFS was 3.7 months (95% CI, 1.9-7.4).

The most frequently reported grade 3 to 4 adverse event (AE) was anemia; the most common all-grade AE was stomatitis. For patients receiving second-line therapy, the most common grade 3 to 4 AE was hypertension, and the most frequently observed all-grade AEs were stomatitis and weight loss.

The authors concluded 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.”


  1. Royce M, Bachelot T, Villanueva C, et al. Everolimus plus endocrine therapy for postmentopausal women with estrogen receptor-positive, human epidermal growth factor receptor 2-negative advanced breast cancer. JAMA Oncol. 2018 Mar 22. doi: 10.1001/jamaoncol.2018.0060