A lack of toxicity and the shrinking of tumors were at the heart of new interim data produced from a two-stage phase II study by Relay Therapeutics Inc. The company reported that the oral small molecule RLY-4008, designed to elicit responses across a broad spectrum of resistance mutations and in multiple tumor types, selectively inhibited fibroblast growth factor receptor (FGFR) 2 in ways that are not limited by off-target toxicities of hyperphosphatemia (FGFR1) and diarrhea (FGFR4).