Evaluation of [Ac]Ac-DOTA-anti-VLA-4 for targeted alpha therapy of metastatic melanoma.

Unlabelled: Very late antigen 4 (VLA-4; also called integrin α4β1) is overexpressed in melanoma tumor cells with an active role in tumor growth, angiogenesis, and metastasis, making VLA-4 a potential target for targeted alpha therapy (TAT).

Methods: An anti-VLA-4 antibody was conjugated to DOTA for [Ac]Ac-labeling and DTPA for [In]In-labeling. The resulting agents, [Ac]Ac- or [In]In-labeled anti-VLA-4 were evaluated in vitro, including binding affinity, internalization, and colony formation assays as well as in vivo biodistribution studies.