gemcitabine + nab-paclitaxel + sintilimab + bevacizumab

This is a four-drug combination regimen consisting of gemcitabine, nab-paclitaxel, sintilimab, and bevacizumab. - **Gemcitabine** is a nucleoside analog (antimetabolite) that inhibits DNA synthesis, leading to cell death in rapidly dividing cells such as cancer cells[1][2][4]. - **Nab-paclitaxel** (nanoparticle albumin-bound paclitaxel) is a microtubule inhibitor that disrupts mitosis by stabilizing microtubules and preventing their depolymerization[1][2][4]. - **Sintilimab** is a monoclonal antibody targeting the programmed cell death protein 1 (PD-1), acting as an immune checkpoint inhibitor to enhance T-cell mediated anti-tumor responses. - **Bevacizumab** is a recombinant humanized monoclonal antibody that binds vascular endothelial growth factor A (VEGF-A), inhibiting angiogenesis required for tumor growth and metastasis[6][7]. This combination brings together cytotoxic chemotherapy (gemcitabine and nab-paclitaxel), immunotherapy (sintilimab), and targeted antiangiogenic therapy (bevacizumab). It has been investigated primarily for advanced or metastatic pancreatic cancer but may be explored in other solid tumors.