ERBB2 and carcinosarcoma: Zanidatamab (ZW25), a humanized, bispecific antibody that is simultaneously attached to the two HER2 epitopes bound by trastuzumab and pertuzumab, has demonstrated safety and efficacy in HER2+ tumors in a phase 2 study; this study evaluated zanidatamab in patients with HER2-positive metastatic endometrial carcinoma/carcinosarcoma in ≥2nd line but did not meet its primary efficacy endpoint.