Biodistribution of anti-CEA F(ab')(2) fragments after intra-arterial and intravenous injection in patients with liver metastases due to colorectal carcinoma

The biodistribution of simultaneous intra-arterial and intravenous injections of a radiolabelled anti-CEA MAb F(ab')(2) fragment was studied in three patients with Liver metastases from colorectal cancer. Identical MAb fragments, labelled with either I-125 or I-131 were injected over a period of 30 min into the hepatic artery and into a peripheral vein. After 1 or 2 days, biodistribution was measured in the surgically removed metastases, normal tissue samples and blood. By tissue radioactivity counting, tumour uptake in the range 6.3-9.1% of injected dose per gram was found. Superimposable metastasis-to-blood and metastasis-to-normal liver ratios were obtained for both iodine isotopes in all three patients. The results indicate that the intra-arterial injection of MAb F(ab')(2) fragments gives no measurable advantage over more convenient injections into a peripheral vein.