S 3304 is a potent, orally active, noncytotoxic inhibitor of matrix metalloproteinases, primarily MMP-2 and MMP-9 that was developed by Shionogi as an anticancer agent. This drug has prolongs survival in mice xenografts and was well tolerated in healthy volunteers. S 3304 had completed phase I clinical trials for patients with locally advanced non-small cell lung cancer and with advanced solid tumors, however, the company had discontinued the further development of S 3304.