PU-H71 is a potent and selective inhibitor of HSP90 with IC50 of 51 nM. 

PU-H71, a novel HSP90 inhibitor in Ewing sarcoma cell lines, Hsp90 plays a critical role in modulating the activity of many cell signaling proteins and are an attractive target for anti-cancer therapeutics. Studies indicate that PU-H71(Hsp90 inhibitors) may serve as potential anti-Parkinson′s disease. PU-H71. Potent and durable anti-tumor effects in TNBC xenografts, including complete response and tumor regression, without toxicity to the host are achieved with this agent. Notably, TNBC tumors respond to retreatment with PU-H71 for several cycles extending for over 5 months without evidence of resistance or toxicity.