PHARMACOKINETICS, BIODISTRIBUTION AND DOSIMETRY OF ANTI-NCAM MONOCLONAL-ANTIBODY RNL-1 AND ITS FRAGMENTS IN EXPERIMENTAL LUNG-CANCER

The in vitro binding characteristics and the in vivo distribution in t umor-bearing mice of radioiodinated intact IgG, F(ab')(2) and Fab frag ments of RNL-1 (anti-NCAM MAb) were compared. Affinity constants were in the same range for IgG and F(ab')(2) (5x10(7) M(-1)), while the Fab fragment exhibited a 10-fold lower binding affinity for the NCAM-anti gen (5x10(6) M(-1)). Maximum tumor uptake for RNL-1 IgG and the respec tive fragments were 13.5%. 4.5% and 3.4% ID/g. Tumor-to-non-tumor rati os were highest for F(ab')(2) fragments of RNL-1, Dosimetric analysis of the biodistribution data indicated that highest radiation doses cou ld be guided to the tumors when the I-131-labelled intact RNL-1 IgG wa s used.