The experimental study on the radioimmunotherapy of the nasopharyngeal carcinoma overexpressing HER2/neu in nude mice model with intratumoral injection of 188Re-herceptin

Purpose: To study the therapeutic efficacy of radioimmunotherapy of 188Re labeled herceptin which is a humanized anti-p185-HER2/neu monoclonal antibody in nude mice bearing nasopharyngeal carcinoma (NPC) expressing the HER2/neu proto-oncogene via different routes of administration. Methods: The nude mice bearing NPC were injected with 188Re-herceptin intratumorally (IT) and intravenously (IV). The biodistribution was observed on day 2 (n=3). The tumor growth inhibition rate was determined by measurement of tumor volume. Results: In the IT-treated mice, tumor uptake of 188Re-herceptin was significantly greater than in the IV-treated mice (11.53% ID/g vs 2.79% ID/g at 48 h), and lower normal organ uptake was also seen. The IT administration of 188Re-herceptin caused greater inhibition of tumor growth at the fourth week as compared to the IV administration. Conclusions: We conclude that intratumoral administration of 188Re-herceptin makes high level of radioactivity retained in tumor with significantly lower radioactivity retained in normal tissues, and provides a more effective regional therapy for nasopharyngeal carcinoma overexpressing HER2/neu. (authors)