Refractory Wilms Tumor

This phase I/II trial studies the effects of trastuzumab deruxtecan (DS-8201a) in treating patients with osteosarcoma, Wilms tumor (WT) or desmoplastic small round cell tumor (DSRCT) that is newly diagnosed or has come back after a period of improvement (recurrent) or that has not responded to previous treatment (refractory). Trastuzumab deruxtecan is in a class of medications called antibody-drug conjugates. It is composed of a monoclonal antibody, called trastuzumab, linked to a chemotherapy drug, called deruxtecan. Trastuzumab attaches to HER2 positive tumor cells in a targeted way and delivers deruxtecan to kill them.