Everolimus combined with endocrine therapy in advanced HR-positive, HER2-negative Chinese breast cancer patients: A retrospective study.

e13023 Background: The Food and Drug Administration (FDA) approves the combination of everolimus and exemestane for the treatment of advanced breast cancer patients who are hormone-receptor (HR) positive but human epidermal growth factor receptor-2 (HER2) negative. However, there is little real-world data on the everolimus in Chinese breast cancer patients. Endocrine therapy is the main treatment for advanced HR-positive, HER2-negative breast cancer patients which includes aromatase inhibitor (AI) or fulvestrant. Drug resistance and subsequent treatment after endocrine therapy are some of the most clinical concerns. CDK4/6 inhibitors and HDAC inhibitors are poorly available due to high price, and combined everolimus therapy can be a non-ignorable choice for advanced HR-positive, HER2-negative breast cancer patients. Methods: We retrospectively collected the treatment information of advanced breast cancer patients treated with everolimus from 2013 to 2020 in Zhejiang Cancer Hospital. Kaplan–Meier analysis and Cox regression methods were used to calculate and compare the progression-free survival (PFS). Results: The study finally enrolled 84 patients meeting the requirement, and patients were postmenopausal or premenopausal while received ovarian function suppression. And 54 patients were in the everolimus+AI group, 30 patients were in the everolimus+fulvestrant group. The median PFS in all 84 patients was 6.87 months, and the median overall survival (OS) was 28.87 months. The DCR in all 84 patients was 76.2%, and the most common grade 3-4 adverse event is stomatitis which is similar to other previous studies. Subgroup analyses were further performed based on everolimus combined with AI/fulvestrant. Patients were well-balanced in clinical characteristics in the two groups. Everolimus combined with fulvestrant group showed no superior to everolimus combined with AI group, 5.77 vs. 7.97 months (HR, 1.56; 95% CI, 0.92-2.65, P = 0.0735). Subgroup analyses showed everolimus combined with AI groups was superior to Everolimus combined with fulvestrant groups in some subgroups: postmenopausal group (HR, 0.50; 95% CI, 0.26-0.98); without bone metastasis group (HR, 0.22; 95% CI, 0.06-0.80); lung or pleura metastasis group (HR, 0.35; 95% CI, 0.16-0.77); visceral disease group (HR, 0.37; 95% CI, 0.20-0.69); previous therapy lines ≥ 4 group (HR, 0.44; 95% CI, 0.22-0.87). Conclusions: Everolimus combined with fulvestrant is not superior to everolimus combined with AI in HR-positive, HER2-negative breast cancer patients. For postmenopausal patients, patients without bone metastasis, and patients with visceral disease, everolimus combined with AI is a better choice.