Here, we evaluated ISM5043, a novel, small molecule KAT6 inhibitor for anti-tumor effects in ER+/HER2- breast cancer cell lines and animal models.In the ZR-75-1 (ER+, HER2-) xenograft model, ISM5043 demonstrated robust and dose dependent anti-tumor activity, as monotherapy, with Tumor Growth Inhibition (TGI) between 80~110% at doses ranging from 0.3 to 10 mg/kg, QD….