In the imaging of tumors using radiolabeled monoclonal antibodies, the use of PET gives increased sensitivity over conventional gamma camera imaging techniques. Copper-64, a positron-emitting radionuclide, has been labeled to 1A3, an anticolorectal carcinoma monoclonal antibody, and its fragments 1A3- F(ab')2 utilizing the bifunctional chelate Br-benzyl-TETA. The 64Cu- labeled intact 1A3 and 1A3-F(ab')2 have been evaluated as potential imaging agents for PET. Biodistribution studies of 64Cu-benzyl-TETA-1A3 and 64Cu- benzyl-TETA-1A3-F(ab')2 in tumor-bearing hamsters were compared with those of 111In-BrΦHBED-1A3, 111In-BrΦHBED-1A3-F(ab')2 and 126I-labeled intact 1A3 and 1A3-F(ab')2. Tumor uptake of 64Cu-labeled intact 1A3 and fragments in the hamster model was superior to both 111In- and 125I- labeled intact 1A3 and fragments. Human dosimetry data for 64Cu- and 123I-labeled 1A3 and 1A3-F(ab')2 were calculated from biodistribution data in rats. High kidney uptake of 64Cu-benzyl-TETA-1A3-F(ab')2 precludes clinical study at this time; however, the data shows that 64Cu-benzyl-TETA- 1A3 would be suitable for positron tomography imaging of colorectal cancer in patients.
|Number of pages||7|
|Journal||Journal of Nuclear Medicine|
|State||Published - Jan 1 1992|