fruquintinib + sintilimab + pemetrexed + carboplatin

This is a four-drug combination regimen consisting of fruquintinib, sintilimab, pemetrexed, and carboplatin. Fruquintinib is a highly selective small molecule inhibitor of vascular endothelial growth factor receptors 1, 2, and 3 (VEGFR1/2/3), which inhibits tumor angiogenesis. Sintilimab is a monoclonal antibody targeting programmed death-1 (PD-1), functioning as an immune checkpoint inhibitor to enhance anti-tumor immune responses. Pemetrexed is an antimetabolite chemotherapy agent that inhibits multiple folate-dependent enzymes involved in nucleotide synthesis, leading to inhibition of DNA and RNA synthesis in rapidly dividing cells. Carboplatin is a platinum-based chemotherapeutic that causes DNA crosslinking and apoptosis in cancer cells. This combination leverages antiangiogenic therapy (fruquintinib), immunotherapy (sintilimab), and cytotoxic chemotherapy (pemetrexed plus carboplatin) for synergistic anti-tumor effects.