The Effects of Anlotinib Combined with Chemotherapy following Progression on Cyclin‐Dependent Kinase 4/6 Inhibitor in Hormone Receptor‐Positive Metastatic Breast Cancer

Abstract

Purpose. Endocrine therapy combined with cyclin‐dependent kinase (CDK) 4/6 inhibitors (CDK4/6i) is the preferred treatment for hormone receptor‐positive (HR+)/human epidermal growth factor receptor 2‐negative (HER2–) metastatic breast cancer (MBC). However, there are currently no recommendations for therapeutic strategies after progression on CDK4/6i‐based treatment. This study aimed to examine the efficacy and safety of anlotinib plus chemotherapy in HR+/HER2– MBC after progression on CDK4/6 inhibitors. Methods. We collected data from 32 patients with HR+/HER2– MBC treated with anlotinib plus chemotherapy after progressing on CDK4/6i at Jiangsu Cancer Hospital from March 2020 to October 2023. The median follow‐up was 9.1 months (range, 2.0–19.7 months) as of the data cutoff date in October 2023. The primary endpoint was median progression‐free survival (PFS); secondary endpoints included objective response rate (ORR), disease control rate (DCR), and adverse events. Results. The median PFS (mPFS) of all patients was 7.6 months (95% confidence interval (CI), 5.75–9.45). There was no significant difference in mPFS between patients who responded to prior CDK4/6i treatment and those who did not (8.3 months vs. 6.8 months, p = 0.580). Besides, the ORR was 34.4% and DCR was 93.8%. The most frequently observed adverse events were anemia (50.0%), neutropenia (40.6%), thrombocytopenia (34.4%), and epistaxis (34.4%). Dose interruption or reductions due to adverse events occurred in 2 (6.3%) and 5 (15.6%) patients, respectively. Conclusions. The study preliminarily demonstrates that anlotinib combined with chemotherapy may be an optional recommendation for patients with HR+/HER2– metastatic breast cancer who have progressed after CDK4/6i.