TX-245

TX-245 is a preclinical-stage small molecule bis-benzamide designed to target and inhibit the mutant estrogen receptor alpha (ESR1), specifically the common Y537S and D538G mutations. Developed by researchers at UT Southwestern Medical Center, UT Health San Antonio, and the University of Texas at Dallas, and licensed by EtiraRx, TX-245 acts as a selective estrogen receptor degrader/downregulator (SERD) and antagonist. It downregulates estrogen receptor (ER) protein expression, blocks ER-chromatin interactions, and suppresses ER-mediated transcriptional signaling. In preclinical models of metastatic breast cancer, including those resistant to fulvestrant and tamoxifen, TX-245 has demonstrated significant anti-proliferative activity, tumor regression (both as a monotherapy and in combination with palbociclib), and inhibition of metastatic progression.