RET and neoplasm: Ponatinib, another TKI, was tested in RET fusion-positive CRC patient-derived xenograft (PDX) models compared to the standard of care agent 5-FU and demonstrated greater efficacy in the NCOA4-RET model (79% of tumor growth inhibition) and in the CCDC6-RET model (almost complete regression), identifying this drug as the most potent RET inhibitor tested [113].