giredestrant + abemaciclib + atezolizumab

**giredestrant + abemaciclib + atezolizumab** is an investigational pharmaceutical combination being evaluated for the treatment of estrogen receptor-positive (ER+), human epidermal growth factor receptor 2-negative (HER2–) locally advanced or metastatic breast cancer. - **Giredestrant** is a potent, oral, non-steroidal selective estrogen receptor degrader (SERD) that antagonizes and degrades the estrogen receptor, disrupting estrogen signaling pathways crucial for hormone-dependent breast cancers[5]. - **Abemaciclib** is a small molecule selective inhibitor of cyclin-dependent kinases 4 and 6 (CDK4/6), leading to cell cycle arrest and apoptosis in cancer cells by inhibiting phosphorylation of retinoblastoma protein (Rb)[5]. - **Atezolizumab** is a humanized monoclonal antibody targeting programmed death-ligand 1 (PD-L1), acting as an immune checkpoint inhibitor to restore antitumor immune response[3]. This combination is under investigation in early phase clinical trials for breast cancer, with safety and efficacy still being evaluated[1][4][7]. Developers include Roche and its US affiliate Genentech[5][7]; abemaciclib is developed by Eli Lilly, and atezolizumab by Roche/Genentech.