PEN-866 is a potential agent for controlling early stage tumor growth for non-small cell lung cancer (NSCLC). PEN-866 is a novel esterase-cleavable conjugate of an HSP90i and a topoisomerase I inhibitor, SN-38
PEN-221 is a Somatostatin receptor 2 (SSTR2)-targeting cytotoxic conjugate with an IC50 of 10 nM. PEN-221 is a conjugate consisting of microtubule-targeting agent DM1 linked to the C-terminal side chain of Tyr3-octreotate.