sunitinib + pazopanib + bevacizumab + everolimus

This is an experimental combination therapy consisting of four agents—sunitinib, pazopanib, bevacizumab, and everolimus—each with distinct but complementary mechanisms targeting angiogenesis and tumor cell proliferation. Sunitinib and pazopanib are small molecule tyrosine kinase inhibitors (TKIs) that primarily inhibit vascular endothelial growth factor receptors (VEGFRs), platelet-derived growth factor receptors (PDGFRs), and other kinases involved in tumor angiogenesis. Bevacizumab is a monoclonal antibody that binds to VEGF-A, preventing it from activating VEGF receptors on the surface of endothelial cells. Everolimus is an mTOR inhibitor that blocks a key pathway involved in cell growth, proliferation, and survival. The rationale for combining these agents is to achieve more comprehensive inhibition of angiogenic pathways and tumor progression by targeting both upstream ligands/receptors (VEGF/VEGFR) and downstream signaling pathways (mTOR). However, clinical experience with combinations involving two or more of these drugs has shown significant toxicity concerns without clear evidence of superior efficacy over sequential monotherapy or simpler combinations[2][3][6][7]. There are no approved regimens or large-scale trials specifically evaluating the quadruple combination; most studies have focused on doublet or triplet regimens.