ATV-1601 + fulvestrant

ATV-1601 + fulvestrant is an investigational oral combination therapy being studied for advanced solid tumors and hormone receptor-positive/HER2-negative metastatic breast cancer characterized by the AKT1 E17K mutation. ATV-1601 is a highly selective, non-covalent, allosteric inhibitor targeting the AKT1 E17K mutant, exhibiting strong selectivity over AKT2[9][8]. It is distinguished from pan-AKT inhibitors by sparing AKT2 and demonstrating improved target engagement, efficacy, and tolerability in preclinical models[2][6][9][10]. Fulvestrant is a well-established selective estrogen receptor degrader (SERD) that acts by antagonizing and degrading estrogen receptors. Combination rationale: The therapy is designed for patients whose tumors may be driven both by AKT1 E17K signaling and estrogen receptor pathways. The aim is to provide targeted, tumor-specific inhibition while mitigating resistance mechanisms that often arise when either pathway is inhibited alone[1][4]. Primary indication: Advanced or metastatic hormone receptor-positive/HER2-negative breast cancer with AKT1 E17K mutation[1][4][7]. ATV-1601 is also being studied as monotherapy and combination therapy for various advanced solid tumors[7].