Breast cancer is the most common cancer in women worldwide. One in 8 women in the United States will develop breast cancer in her lifetime. Over 70% of breast cancers are estrogen receptor (ER) positive, therefore hormone therapies that directly antagonize ER function (e.g., tamoxifen) or block the production of the estrogen (e.g., aromatase inhibitors) are key to the management of the disease in both adjuvant and metastatic settings. Despite initial efficacy seen with endocrine therapies, the development of acquired resistance ultimately limits the use of these agents although the majority of tumors continue to require ERα for growth.

AND019 is a novel third generation selective estrogen receptor degrader (SERD), which is a competitive antagonist of estrogen receptor (ER) by binding with ERα to mediate its degradation. It also has the potential to overcome hormone therapy resistant ER-dependent tumors. A Phase I First-in-Human (FIH) study of AND019 is under IND filing in China and IND submission in the US is in process.