YH32367 stimulated IFN-γ secretion and thereby inducing tumor cells lysis in co-culture assay with hPBMC and HER2-expressing tumor cells. YH32367 also showed superior efficacies on immune cells activation as well as tumor growth inhibition in both HER2-expressing tumor-bearing hPBMC humanized mice...It suggests that YH32367 could be promising to develop for the patients with HER2 positive cancer as an effective HER2-directed therapy.