A multicenter real-world study on the efficacy and safety of anlotinib-based treatment for metastatic breast cancer.

e13120 Background: Anlotinib is a multi-targeted small molecule receptor tyrosine kinase (RTK) inhibitor that inhibits angiogenesis. There is only one phase II study on the use of anlotinib in advanced breast cancer (MBC). Therefore, this study aims to analyze its efficacy and safety in the treatment of BC in the real world. It has been approved for the treatment of advanced non-small cell lung cancer and soft tissue sarcoma. There is limited research on the use of anlotinib in advanced breast cancer (MBC). Methods: This study retrospectively analyzed the clinical data of MBC patients who received anlotinib treatment at four domestic centers from January 2021 to December 2023. The primary endpoint was progression-free survival (PFS), and secondary endpoints included overall survival (OS), objective response rate (ORR), disease control rate (DCR), and safety. Kaplan-Meier analysis was used to analyze PFS and OS, and Cox regression model was used to analyze the hazard ratios (HRs) of anlotinib-based treatment on PFS and OS in different subgroups of patients. A p-value <0.05 was considered statistically significant. Results: A total of 153 MBC patients receiving anlotinib-based treatment were included from four centers. The median age was 51 years (range: 22-76), and the median number of prior lines of therapy was 3. The median PFS was 7.7 months (range: 5.2-10.1 months), and the median OS was 28.0 months (range: 21.4-34.9 months). The median ORR and DCR were 19.6% and 60.1%, respectively. The ORR for HR+/HER2- and triple-negative breast cancer patients was 11.6% and 28.8%, respectively, DCR for HR+/HER2- and triple-negative breast cancer (TNBC) patients was 55.8% and 59.6%, respectively. The median PFS was 9.0 months (range: 6.0-11.9 months) for HR+/HER2- patients and 5.3 months (range: 3.5-7.0 months) for TNBC patients, while the median OS was 33.0 months (range: 24.4-41.5 months) and 14.0 months (range: 9.5-18.4 months), respectively. In the subgroup analysis, age <60 years, initial stage IV disease, Ki67≤60%, and treatment with PD-L1 monoclonal antibodies-based regimen were associated with PFS benefit. ECOG <2 and treatment with PD-L1 monoclonal antibodies-based regimen were associated with prolonged OS. Among the 31 patients with brain metastases receiving anlotinib treatment, 11 had active brain metastases and 20 had stable brain metastases. The median PFS was 8.0 months. The intracranial ORR was 12.9%, and the intracranial DCR was 61.3%. No serious adverse events or treatment-related deaths occurred. Grade I/II adverse reactions included hand-foot syndrome (22.2%) and fatigue (19.6%), while grade III/IV adverse reactions included fatigue (6.5%) and decreased neutrophil count (5.2%). Three patients required dose reduction due to intolerable adverse reactions, and nine patients discontinued treatment. Conclusions: Anlotinib demonstrates good antitumor activity and safety in the treatment of MBC. When combined with chemotherapy or immunotherapy, it can improve PFS and OS without significantly increasing toxicity. In particular, it shows promising intracranial ORR and PFS in patients with brain metastases. Clinical trial information: NCT04541420 .