ERBB2 and breast cancer: SGNTUC-019 is an ongoing Phase II basket trial (NCT04579380) with dual targeting of HER2 with tucatinib (Tukysa®®), a HER2 kinase inhibitor also used in the treatment of HER2+ breast cancer, and trastuzumab in patients with previously treated solid tumors, including urothelial carcinoma [51].