Hpn536 is a tri-specific, T-cell–activating protein-based construct that binds to mesothelin (MSLN)-expressing tumor cells and CD3ϵ on T cells, leading to T-cell activation and potent redirected target cell lysis. It also binds to serum albumin, extending its plasma half-life. HPN536 demonstrates extended half-life in nonhuman primates (NHP) and has the potential to treat mesothelin-expressing solid tumors. MW: 52.92 KD.