The therapeutic efficacy of mAbs directed against antigens expressed on solid tumors is often limited by their poor accumulation in and dispersal throughout the tumor tissues. To exert therapeutic effects, systemically administered mAbs need to selectively home to tumor vessels, cross the blood vessels into the perivascular tumor parenchyma, and then spread into the inside of the tumor tissues by diffusion or convection to reach as many tumor cells as possible.

 We have developed solid tumor-tissue penetrating antibody, so called mAb-TPP, in which the Tissue Penetrating Peptides (TPPs) were genetically fused to antibody. The mAb-TPP is a superior format for solid tumor-targeting antibodies due to its enhanced tumor tissue penetration and greater antitumor efficacy compared with conventional mAbs.

 Further, immunoglobulin Fc-fused TPP format, Fc-TPP, can be used as a promoter agent to improve extravasation and tumor-penetration of anti-cancer drugs or tumor-imaging agents.