Abstract 5236: Complete response to selpercatinib (LOXO-292), a highly selective RET inhibitor, in a patient with RET fusion-positive breast cancer

Background: Activating RET gene fusions have been reported in diverse solid tumors but 150 days, with all adverse events grades 1-2, and most recovered and none requiring dose interruption or modification. Conclusion: Selpercatinib demonstrated anti-tumor activity in a patient with RET fusion-positive breast cancer. To our knowledge, this is the first report of a breast cancer patient with a sustained response to selective, RET-targeted therapy and adds to the diversity of RET fusion-positive tumor types that may benefit from selective RET inhibition. Citation Format: Masayuki Takeda, Satomi Watanabe, S. Michael Rothenberg, Jennifer