Antitumor effect of MCC‐465, pegylated liposomal doxorubicin tagged with newly developed monoclonal antibody GAH, in colorectal cancer xenografts

MCC‐465 is an immunoliposome‐encapsulated doxorubicin. The liposome is tagged with polyethylene glycol and the F(ab)2 of a monoclonal antibody named GAH, a human antibody obtained by the hybridoma technique. The epitope recognized by GAH is not well characterized, but human gastric, colorectal, and mammary cancer cells were GAH‐positive, while the normal counterparts were GAH‐negative. Pegylated liposome doxorubicin (PLD) and MCC‐465 did not show significant antitumor activity against GAH‐negative Caco‐2 xenografts. On the other hand, MCC‐465 exhibited significantly superior antitumor effects against GAH‐positive WiDr‐Tc and SW837 xenografts, compared with PLD. Immunohis‐tochemistry with GAH revealed that 94% (100 of 106) of surgical specimens of colorectal cancer were GAH‐positive. These results warrant a phase I clinical trial of MCC‐465 for patients with metastatic colorectal cancer.