Biodistribution of Neocarzinostatin Conjugated to Chimeric Fab Fragments of the Monoclonal Antibody A7 in Nude Mice Bearing Human Pancreatic Cancer Xenografts

In this study, we conjugated chimeric Fab fragments of the monoclonal antibody (MAb) A7, which reacts with pancreatic cancers, to the antitumor drug neocarzinostatin (chA7Fab‐NCS) and intravenously injected (125)I‐labeled chA7Fab‐NCS into nude mice bearing a human pancreatic cancer xenograft. We compared the tumor localization of (125)I‐labeled chA7Fab‐NCS with that of conventional (125)I‐labeled A7‐NCS, which was produced by conjugation of MAb A7 and NCS. (125)I‐Labeled chA7Fab‐NCS accumulated in the tumor earlier than (125)I‐labeled A7‐NCS, and significantly larger amounts of (125)I‐labeled chA7Fab‐NCS had accumulated in the tumor 1 hour after injection. The results suggest that chA7Fab may be a suitable carrier for NCS in immunotargeting therapy against pancreatic cancer.