PF-04929113 (SNX-5422) is a potent and selective Hsp90 inhibitor (Kd of 41 nM). PF-04929113 also inhibits Her-2 degradation (IC50 of 37 nM). PF-04929113 is a small-molecule Hsp90 inhibitor based on the 6,7-dihydro-indazol-4-one scaffold. PF-04929113 exhibits potent effects on Her-2 stability and causes expected up-regulation of Hsp70. PF-04929113 shows potent antiproliferative activity against a broad range of cancer cell types, e.g. MCF-7 (IC50=16 nM), SW620 (IC50 of 19 nM), K562 (IC50 of 23 nM), SK-MEL-5 (IC50 of 25 nM), and A375 (IC50 of 51 nM).
