Moreover, MM­302 and trastuzumab bind to different HER2 epitopes, and the combination of MM-302 and trastuzumab demonstrated superior antitumor activity to either agent alone in HER2­overexpressing tumor xenograft models (unpublished observations, Chris Espelin, Shannon Leonard, and Elena Geretti; Merrimack Pharmaceuticals, Inc., Cambridge, MA, USA). This evidence concerns the gene ERBB2 and neoplasm.