The effect of radiosensitizers on radio-immunotherapy, using 131I-Labelled anti-cea antibodies in a human colonic xenograft model

✍ Scribed by R. Barbara Pedley; Richard H. J. Begent; Joan A. Boden; Robert Boden; Theresa Adam; Kenneth D. Bagshawe

• Publisher: John Wiley and Sons
• Year: 1991
• Tongue: French
• Weight: 683 KB
• Volume: 47
• Category: Article
• ISSN: 0020-7136
• DOI: 10.1002/ijc.2910470420

✦ Synopsis

Anti-CEA antibodies were used for radio-immunotherapy in an established LS174T colonic xenograft in nude mice. A single IV dose of either I3'I-PK4S (polyclonal) or -A5B7 (monoclonal) antibody produced tumour regression, and sig- nificantly delayed subsequent tumour growth. Administration of a clearing second antibody, 24 hr post '3'I-PK4S and at 5 times the dose, significantly reduced the therapeutic effect of radio-antibody alone. Tumours of mice given non-specific antibody or unlabelled anti-CEA antibody grew like those of untreated controls. In an attempt to enhance therapy without increasing dose, radiosensitizers normally employed with external beam radiation were used in combination therapy. When the hy oxic cell radiosensitizer misonidazole was combined with p3'I-A587, it significantly prolonged tumourgrowth inhibition over radio-antibody alone. Conversely, the therapeutic effect of either radio-antibody was significantly reduced when used in combination with the halogenated pyrimidine radiosensitizer 5-iododeoxyuridine. Neither sensitizer alone affected tumour growth.

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