Associating retinal drug exposure and retention with the ocular toxicity profiles of Hsp90 inhibitors.

3086 Background: In clinical trials certain Hsp90 inhibitors, including AUY922, SNX-5422, and 17-DMAG have caused visual symptoms suggesting retinal dysfunction; others, including ganetespib and 17-AAG, have not. Previous animal toxicology experiments have suggested that retinal changes may be linked to photoreceptor degeneration or cell death. Here histopathologic changes and/or exposure profiles of Hsp90 inhibitors with or without clinical reports of ocular toxicity were evaluated to understand the observed differences in toxicity profile between agents in this class. Methods: We reviewed visual symptoms among subjects administered ganetespib, a potent Hsp90 inhibitor currently in phase II trials; evaluated retinal morphology in rats and cyno monkeys given ganetespib; and compared TUNEL-positive photoreceptors and drug exposure profiles in the retina of rats treated with AUY922, 17-DMAG, and 17-AAG. Studies of ganetespib’s retinal pharmacokinetics and photoreceptor toxicity in rats are ongoing. Results:...