[225Ac]Ac-macropa-rituximab

[225Ac]Ac-macropa-rituximab is a targeted alpha-therapy (TAT) radioimmunoconjugate consisting of the anti-CD20 monoclonal antibody rituximab, conjugated via the macrocyclic chelator macropa to the alpha-emitting radioisotope actinium-225 ([225Ac]Ac). Rituximab provides high-affinity binding to the CD20 antigen, which is expressed on the surface of normal and malignant B-cells. The macropa chelator is specifically utilized for its ability to complex large metal ions like [225Ac]Ac with high stability. Upon binding to target cells, the [225Ac]Ac isotope undergoes decay, releasing high-energy alpha particles that induce complex double-strand DNA breaks within a short range (50-100 μm), effectively killing the target cell while minimizing damage to surrounding healthy tissue. In preclinical research, such as studies conducted at the University of Saskatchewan and CHU de Québec-Université Laval, this conjugate is frequently employed as a non-targeting control to validate the specificity of other alpha-emitting radioimmunoconjugates in CD20-negative tumor environments.

Other names

[225Ac]Ac-Macropa-Rituximab