90Y-besilesomab

**90Y-besilesomab** is an investigational CD66-targeted radioimmunotherapy for bone-marrow conditioning before hematopoietic stem-cell transplantation. It consists of the murine IgG1 anti-CD66 monoclonal antibody besilesomab, chelated with DTPA and radiolabeled with the beta-emitting isotope yttrium-90. Following intravenous administration, it binds CD66 isoforms expressed predominantly on myeloid-lineage marrow cells and can localize radiation to red marrow and spleen, causing targeted marrow ablation while limiting radiation exposure to non-hematologic organs. Telix develops the asset as TLX66 for transplant conditioning in systemic AL amyloidosis, multiple myeloma, and high-risk leukemia. ([telixpharma.com](https://telixpharma.com/news-views/trala-study-of-tlx66-in-al-amyloidosis-presented-at-ash-2021/))

Brand names

TLX66TLX-66TLX 66

Other names

90Y-DTPA-besilesomabyttrium-90-labelled anti-CD66 monoclonal antibodyyttrium90-labelled anti-CD66 monoclonal antibodyyttrium 90-labelled anti-CD66 monoclonal antibody90Y-anti-CD6690Y-anti-CD66-MTR