M9466 + carboplatin + etoposide + atezolizumab

**M9466 + carboplatin + etoposide + atezolizumab** is an investigational combination regimen comprising a novel oral PARP1 inhibitor (M9466, also known as HRS-1167), the platinum-based chemotherapy agent carboplatin, the topoisomerase II inhibitor etoposide, and the anti-PD-L1 monoclonal antibody atezolizumab. This combination is in clinical development primarily for the treatment of extensive-stage small cell lung cancer (ES-SCLC), particularly as a first-line treatment for newly diagnosed cases. M9466 (HRS-1167) acts as a DNA damage repair pathway inhibitor via potent and selective inhibition of poly(ADP-ribose) polymerase 1 (PARP1), sensitizing cancer cells to DNA-damaging agents; carboplatin and etoposide are established cytotoxic chemotherapy drugs; atezolizumab is a humanized monoclonal antibody that blocks Programmed Death-Ligand 1 (PD-L1), thereby enhancing anti-tumor immune responses. The combination is designed to exploit complementary mechanisms to improve treatment outcomes in SCLC and potentially other solid tumors[2][3][5][9].