atezolizumab + idasanutlin

Atezolizumab + idasanutlin is an investigational **combination drug** consisting of the **anti-PD-L1 monoclonal antibody** atezolizumab and the **MDM2 antagonist** idasanutlin. Atezolizumab blocks PD-L1 to enhance T-cell mediated anti-tumor immune responses, while idasanutlin inhibits MDM2, restoring p53 function and promoting apoptosis in cancer cells. This combination is being explored specifically in hormone receptor-positive, *TP53*-wild-type metastatic breast cancer, aiming to increase response rates to immune checkpoint inhibition by targeting both immune evasion and cell survival pathways[1][3][5]. Preliminary studies show some clinical activity and immune modulation, though trials are at early phases with limited patient accrual and no established maximum tolerated dose for the combination[1][3][5].