The anti-tumor efficiency of low-dose apatinib-based chemotherapy in pretreated HER2-negative breast cancer with brain metastases

BACKGROUND: More than half of the metastatic breast cancer patients with brain metastases (BCBM) are HER-2 negative, and the prognosis of HER2-negative BCBM is dismal. But few clinical trials have investigated systemic therapies for this subgroup of patients. METHODS: This real-world study included 58 HER2-negative BCBMs who received low-dose apatinib (250 mg daily) in combination with chemotherapy between 18 March 2017 and 31 December 2021. The objective response rate (ORR) of the central nervous system, clinical benefit rate (CBR), progression-free survival of central nervous system (CNS-PFS) and overall survival (OS) were analyzed. Univariate and multivariate Cox regression model was used to estimate the prognostic factors for CNS-PFS and OS. RESULTS: At the cut-off date, the median follow-up time was 28.2 months. Of the 58 patients, 36 patients were HR+/HER2-, and 22 patients were TNBC. The CNS-ORR was 17.2% (95%CI 9.6% to 28.9%) and the CBR was 53.4% (95%CI 40.8% to 65.7%). The median duration of CNS-PFS for the entire cohort was 6.4 months, and the median OS was 10.7 months. The median CNS-PFS and OS were not affected by hormone receptor status, disease-free survival, the number of prior lines of therapy and local treatment. The most common grade 2–3 adverse events associated with low-dose apatinib were hypertension (20.6%), elevated bilirubin (10.4%), hypothyroidism (10.3%), and hand-foot skin reaction (10.3%). CONCLUSION: Apatinib-based chemotherapy demonstrates potential feasibility with acceptable tolerance for HER2-negative BCBM. Its clinical application in BCBM still needs further verification.