Page 191 - 89Zr-Immuno-PET:Towards a Clinical Tool to Guide Antibody-based Therapy in Cancer

Towards 89Zr-immuno-PET to measure target engagement of antibodies
target engagement for other 89Zr-labeled mAbs, a multiple time point pilot study (with at least 3 late time points) is advised to determine the contribution of non- specific uptake as a function of time and mAb dose. This knowledge can be used to optimize study design and assess whether single time point scanning to detect target engagement is feasible and at which time point. This concept is widely applicable as mAbs and mAb conjugates against many target antigens are developed for a broad range of clinical indications.
CONCLUSION
This study shows that non-specific uptake of mAbs for tissues without target expression can be quantified using 89Zr-immuno-PET at multiple time points. These results form a crucial base for measurement of target-engagement by therapeutic antibodies in-vivo with 89Zr-immuno-PET. For future studies, a pilot phase including at least 3 scans at ≥ 1 day p.i., is required to assess non-specific uptake as a function of time, to optimize study design for detection of target engagement.
ACKNOWLEDGEMENTS
We thank Mats Bergstrom (independent external imaging consultant, Uppsala, Sweden) for conceptual support.
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