A Prospective Study on Efficacy and Safety of Anlotinib Combined With Fulvestrant in Patients With HR-positive and HER2-negative, Secondary Endocrine-resistant, Locally Advanced or Metastatic Breast Cancer

This study is a prospective, single-arm, open-label, phase II clinical trial. The secondary endocrine-resistant is defined as disease relapse within 12 months after at least 24 months endocrine adjuvant therapy, or disease progress after at least 6 months endocrine salvage therapy. Eligible patients were treated with oral anlotinib plus intramuscular fulvestrant till disease progression or intolerant toxicity. In the part of statistical analysis, 40 patients are required to have a 80% power to detect significant improvement in median progression-free survival from 5.8 (fulvestrant alone) to 10 (fulvestrant combined with anlotinib) months, if tested at a two-sided significance level of α=0.05.