Tumor targeting with monoclonal antibody B72.3: experimental and clinical results.

Several monoclonal antibodies (Mabs) are currently the subject of active investigation in the diagnostic imaging of human carcinomas [1–11]. While the diagnostic targeting of a primary or metastatic carcinoma lesion with a Mab is an end unto itself, it should also be considered as a first step toward the use of that Mab in tumor therapy. This is particularly true in those studies in which biopsies of tumor and normal tissue are obtained subsequent to radiolabeled Mab administration. Dosimetry calculations can be made by: 1) analysis of these specimens for counts per minute (cpm) of Mab bound per gram of tumor versus cpm of Mab per gram of normal tissues and 2) analysis of the pharmacokinetics of Mab clearance from sera, to estimate the potential therapeutic efficacy of administering higher doses of the same radiolabeled Mab or for administering the same Mab coupled to a more efficient killer isotope. Alternatively, one gains information regarding the use of that Mab in a patient, either coupled to a drug or toxin, or the use of native Mab to elicit effector cell mechanisms.