SNX-2112, a novel 2-aminobenzamide inhibitor of heat shock protein 90 (Hsp90) was discovered by Serenex. This drug was investigated for treatment of different cancer cell lines, including hepatocellular carcinoma cells, breast cancer cells and in combination with 5-fluorouracil in esophageal cancer. However, subsequent development has been discontinued due to ocular toxicity as identified in a phase I study.

Leupeptin is produced by various species of Actinomycetes. It strongly inhibits proteolysis by plasmin, trypsin and papin. Leupeptin is well absorbed through oral route. Leupeptin has been known to cause various neuropathological changes in vivo resembling those of aging or neurodegenerative processes in the human brain, including the accumulation of neuronal processes and neuronal cytoskeletal abnormalities leading to neurofibrillary tangle (NFT)-like formations. In in vitro experiments, leupeptin protects the heart from myocardial stunning. Leupeptin was found to inhibit tumorigenesis in mouse skin induced by a single, noncarcinogenic dose of 7,12- dimethylbenz(a)anthracene followed by repeated application of croton oil. Tumors that had already been induced were scarcely affected by leupeptin.