A randomized Phase 2 RadiCaL trial (Alliance A031801) reported that adding radium-223 to cabozantinib did not prevent serious bone complications in advanced kidney cancer, despite producing a surprising survival signal. The study’s negative bone-complication primary result complicates the justification for the combination under the current endpoint framework. The trial results place radium-223’s role in kidney cancer into sharper context, particularly since radium-223 has established usage elsewhere in metastatic settings. The mention of a survival signal suggests there may be subgroup or endpoint nuances that require additional analysis. The readout will likely influence how developers structure future radiopharmaceutical combinations in solid tumors where balancing skeletal events and overall survival remains central.