[Extraction efficacy on uptake of intraportally injected monoclonal antibody by human colorectal metastases in nude mice].

Route of administration is an important determinant in tumor uptake of monoclonal antibody (mAb). We studied the extraction efficacy of intraportal injection (IP) on tumor uptake over time in hepatic metastases of human colon carcinoma (HT-29LMM) in nude mice. H-15, a murine IgG1 mAb reactive with HT-29LMM was labeled with I-125, and injected at dose of 0.1 microgram and 1.0 microgram intraportally (IP) or intravenously (IV). More than 3 animals per group were sacrificed immediately, 1 h, 24 h, 72 h, and 120 h following injection. Hepatic metastases, normal liver tissue, and blood were weighted and counted for radioactivity. Compared to IV, IP injection resulted in higher (P less than 0.01) percent injection dose per gram (%ID/g) in metastases at all time points for both doses. Metastases: blood and metastases: liver uptake ratios were higher (P less than 0.05) on day 3 and 5 for both IP doses compared to IV doses. Significant improvement in tumor uptake was seen following IP injection of specific mAb; this has important implications on the design of clinical trials using mAb.