Safety and Pharmacology of SNX-5422 Plus Everolimus in Subjects With Neuroendocrine Tumors

Heat shock protein 90 (Hsp90) plays a central role in the maturation and maintenance of numerous proteins, for example HER2 and mutated EGFR, that are critical for tumor cell viability and growth; SNX-5422 is a pro-drug of SNX-2112, a potent, highly selective, small-molecule inhibitor of the molecular chaperone heat shock protein 90 (Hsp90). Hsp90 has been found to be expressed in 95% of subjects with pancreatic neuroendocrine tumors. This study will determine the MTD of SNX-5422 when given in combination with everolimus in patients with neuroendocrine tumors.The clinical starting dose of 50 mg/m2 qod for SNX-5422 in combination with daily everolimus is 50% of the SNX-5422 qod mono-therapy MTD. The choice to continue once every other day SNX-5422 dosing is based on the safety and efficacy profiles from prior studies, so that drug holidays are interspersed into weekly dosing. The planned subsequent dose levels are 75% and 100% of the SNX-5422 qod mono-therapy MTD.