The Different Strategies for the Radiolabeling of [²¹¹At]-Astatinated Radiopharmaceuticals

Astatine-211 (²¹¹At) has emerged as a promising radionuclide for targeted alpha therapy of cancer by virtue of its favorable nuclear properties. However, the limited in vivo stability of ²¹¹At-labeled radiopharmaceuticals remains a major challenge. This review provides a comprehensive overview of the current strategies for ²¹¹At radiolabeling, including nucleophilic and electrophilic substitution reactions, as well as the recent advances in the development of novel bifunctional coupling agents and labeling approaches to enhance the stability of ²¹¹At-labeled compounds. The preclinical and clinical applications of ²¹¹At-labeled radiopharmaceuticals, including small molecules, peptides, and antibodies, are also discussed. Looking forward, the identification of new molecular targets, the optimization of ²¹¹At production and quality control methods, and the continued evaluation of ²¹¹At-labeled radiopharmaceuticals in preclinical and clinical settings will be the key to realizing the full potential of ²¹¹At-based targeted alpha therapy. With the growing interest and investment in this field, ²¹¹At-labeled radiopharmaceuticals are poised to play an increasingly important role in future cancer treatment.