Breast cancer is one of the most prevalent malignancies in women, with an average of one in eight women worldwide affected by the disease. Among various breast cancer subtypes, approximately 70% are estrogen receptor (ER)-positive. Estrogen receptor antagonists, such as tamoxifen and fulvestrant, serve as the first-line therapeutic agents for ER-positive breast cancer.

However, long-term treatment with these drugs frequently induces ER mutations, which inevitably lead to acquired drug resistance and greatly limit their clinical efficacy and application scope.

AND019 is a third-generation selective estrogen receptor degrader (SERD) independently developed by Andao Pharmaceuticals. By selectively degrading estrogen receptors, AND019 effectively overcomes drug resistance caused by ER mutations. Compared with first and second-generation SERDs, AND019 possesses superior pharmacological efficacy and favorable pharmacokinetic profiles, with no obvious gastrointestinal adverse reactions, demonstrating prominent clinical advantages in both efficacy and safety.