Selective estrogen receptor degraders (SERDs) and covalent antagonists (SERCAs): a patent review (July 2021–December 2023)

INTRODUCTION: Breast cancer is the most frequently diagnosed cancer worldwide. With around 70% of breast cancers expressing the estrogen receptor (ER), molecules capable of antagonizing and degrading ER (SERDs) or covalently binding to and antagonizing ER (SERCAs) are at the forefront of efforts to bring better treatments to patients. AREAS COVERED: This review summarizes patent applications that claim estrogen receptor degraders (SERDs) and covalent antagonists (SERCAs) identified using SciFinder between the period July 2021 to December 2023. A total of 91 new patent applications from 32 different applicants are evaluated with stratification into acidic SERDs, basic SERDs, SERCAs and miscellaneous degraders. EXPERT OPINION: The widespread adoption of fulvestrant in the treatment of ER+ breast cancer continues to stimulate research into orally bioavailable SERDs and SERCAs. A number of molecules have entered clinical development and, although some have been discontinued, a cohort of potential new treatments have generated encouraging efficacy and safety data. Notably, the first example of an oral SERD, elacestrant, has now been approved by the FDA and EMA, providing further encouragement for this class of targeted therapies.