ERBB2 and breast cancer: Surprisingly, one indication received an orphan designation, granted to tucatinib “in combination with trastuzumab and capecitabine for the treatment of adult patients with advanced unresectable or metastatic HER2-positive breast cancer, including patients with brain metastases, who have received one or more prior anti-HER2-based regimens in the metastatic setting” based on the HER2CLIMB trial [23].