A substance being studied in the treatment of advanced pancreatic cancer. Yttrium Y 90 clivatuzumab tetraxetan contains a monoclonal antibody that binds to a protein called MUC-1, which is found on some pancreatic cancer cells. It also contains a radioactive substance called yttrium Y 90, which may help kill cancer cells. Yttrium Y 90 clivatuzumab tetraxetan is a type of radioimmunoconjugate. Also called yttrium Y 90 DOTA monoclonal antibody HuPAM4. OR A radioimmunoconjugate comprised of the humanized monoclonal antibody HuPAM4, directed against the pancreatic cancer antigen MUC1, that is conjugated to the chelating agent tetra-azacyclododecanetetra-acetic acid (DOTA) and radiolabeled with the beta-emitting radioisotope Yttrium Y90. Yttrium Y 90 clivatuzumab tetraxetan binds to tumor cells expressing MUC1 antigen, selectively delivering a cytotoxic dose of beta radiation.