– HPN328 is a humanized trispecific T-cell activating construct (TriTAC) that targets CD3 to engage T cells, targets HSA to extend its half-life, and targets DLL3 on tumor cells. It effectively induces T-cell-mediated cytotoxicity against DLL3-expressing small cell lung cancer (SCLC), leading to tumor regression and sustained antitumor immunity. Molecular weight: 53.06 kDa.