serplulimab + etoposide + carboplatin + cisplatin

This is a combination therapy consisting of serplulimab (an anti-PD-1 monoclonal antibody) with chemotherapy agents etoposide, carboplatin, and cisplatin. Serplulimab works by binding to the PD-1 receptor with high affinity, blocking the interaction between PD-1 and its ligands. This prevents the recruitment of immune co-stimulatory receptor CD28 by PD-1, decreasing the dephosphorylation of CD28 mediated by phosphatase SHP2 and retaining the signal transmitted by CD28. This mechanism enhances the activity of protein kinase AKT, promoting sustained activation of T cells. The combination with chemotherapy agents (etoposide, carboplatin, and cisplatin) has shown significant improvement in overall survival for patients with extensive-stage small cell lung cancer (ES-SCLC).