Cirmtuzumab (also UC-961) is an anti-ROR1 humanised monoclonal antibody.'-mexi-' (melanoma): Ecromeximab§ Cirmtuzumab (also UC-961) is an anti-ROR1 humanised monoclonal antibody. It is an experimental drug in early-stage clinical trials for various cancers including chronic lymphocytic leukemia (CLL).