Monoclonal antibody-drug conjugate, A7-NCS, was applied for 73 patients with colorectal and pancreatic cancer, including metastasis of liver, lung and peritoneum. Monoclonal antibody A7, from a mouse splenocyte immunized against human colon cancer was bound covalently to Neocarzinostatin (NCS), Mitomycin C (MMC) and Adriamycin (ADM) to form A7-NCS, A7-MMC and A7-ADM, respectively. Fifty-four patients with colon cancer, fifteen patients with postoperative liver metastasis of colorectal cancer and one patient with advanced pancreatic cancer were given A7-NCS intra-arterially. Two patients with postoperative lung metastasis of colon cancer were injected intra-venously and one patient with postoperative peritoneal metastasis of colon cancer was given it intraperitoneally. Three patients with liver metastasis showed evidence of tumor reduction on CT scan and three claimed pain relief. Postoperative survival of the patients with distant metastasis exhibited slightly higher survival rate in the patients with A7-NCS, as compared with the patients without A7-NCS. There was no serious adverse effect in the patients given A7-NCS. Human anti-mouse antibody (HAMA) was detected in all patients given the conjugate. Repeated injections of A7-NCS for several consecutive days following the first injection brought about the same A7 pattern as the first injection.