CSF2 and cancer: However, IDO inhibitors do not increase the effectiveness of anti-PD-1/PD-L1 antibodies for T cell-inflamed tumours such as PDACs treated with GVAX therapy (GVAX® is an investigational allogeneic cancer vaccine platform based on the local production of granulocyte-macrophage colony-stimulating factor (GM-CSF) at the vaccine site to generate a systemic tumour-specific immune response) [77].