AC699

AC699 is an orally bioavailable, chimeric protein degrader targeting estrogen receptor alpha (ERα), developed by Accutar Biotechnology. It functions as a proteolysis-targeting chimera (PROTAC) that links ligands for ER and cereblon (CRBN) E3 ubiquitin ligase to induce targeted degradation of ERα. AC699 is being investigated for the treatment of ER-positive, HER2-negative, ESR1-mutated advanced or metastatic breast cancer in patients who have progressed on at least one line of endocrine-based therapy. The drug has demonstrated potent and selective ERα degradation with promising safety and antitumor activity in early clinical trials. It has received FDA Fast Track designation based on phase 1 data showing partial responses and clinical benefit in this patient population[1][2][3][4][5][7].