“… 19 , 20 However, in most cases, IAPi sensitized the cell lines to extrinsic TNF‐α or TNF‐related apoptosis‐inducing ligand (TRAIL), often with synergistic activity when both TNF/TRAIL and a SMAC mimetic were added. 15 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 Several studies by multiple independent research groups have shown synergistic activity of SMAC mimetics when combined with radiation in mice inoculated with xenografts of human HNSCC cell lines, including HPV‐positive/negative models and four different IAPi (birinapant, xevinapant, tolinapant, and LCL161). The anti‐tumor activity of these combinations was remarkable in these aggressive xenograft models, resulting in the cure of most tumor‐bearing mice.…”