Abstract: The invention provides methods of treating solid tumors, such as solid tumors with HER2 alterations, e.g., solid tumors in which HER2 is amplified/overexpressed or mutated, with a combination of tucatinib, or salt or solvate thereof, and at least one anti-HER2 antibody, such as trastuzumab or trastuzumab and pertuzumab.

Abstract: The present disclosure relates to a method for treating or ameliorating the effects of a HER2 positive breast cancer in a subject by administration of a combination of tucatinib and an anti-HER2 antibody-drug conjugate (e.g., ado-trastuzumab emtansine or trastuzumab deruxtecan). In some embodiments, the methods provided herein are useful for treating or ameliorating the effects of a brain metastasis in a subject having a HER2 positive breast cancer by administration of a combination of tucatinib and an anti-HER2 antibody-drug conjugate (e.g., ado-trastuzumab emtansine or trastuzumab deruxtecan).