TAT-10: Preclinical Evaluation of Astatinated Nanobodies for Targeted Alpha Therapy

Kanazawa, Japan (UroToday.com) This study has some similarities to the previous paper in that the nanobody (Nb) 2Rs15d-Nb is employed to target HER2+ SKOV-3 cells. The radioisotope is different with present study using the alpha-emitter At211 instead of Ac225.

To evaluate the yields, purity, and binding three different prosthetic groups were prepared with conjugates m-eATE and SGMAB for 2Rs15d-Nb and MSB for the site-specific 2Rs15d-His6-Linker-Cys. All three gave good yields and purities. The m-eATE with an activity of 118 MBq/mg gave a yield of 55% and purity 99%. The SGMA with activity 68 MBq/mg had yield 28% and purity 99%. Finally the site-specific MSB with activity 270 MBq/mg had yield 52% and purity >91%. The internalized fractions were 24.5%, 11.8%, and 25% at 1 hour and 18.1%, 10.9%, and 9.5% at 24 hours respectively for MSB, SGMAB, and me-ATE.

In vivo studies are planned to both confirm the internalization fractions and explore the biodistribution of the different At211-labeled Nb conjugates.

Presented By: Yana Dekempeneer from Laboratory of In Vivo Cellular and Molecular Imaging, Vrije Univesiiteit Brussels, Brussels, Belgium and Belgian Nuclear Research Center, Mol, Belgium

Written By: William Carithers, Lawrence Berkeley National Laboratory

at the 10th International Symposium on Targeted Alpha Therapy (TAT-10)  May 31 - June 1, 2017 - Kanazawa, Japan.