Synthesis and preclinical characterization of [64Cu]NODAGA-MAL-exendin-4 with a Nε-maleoyl-l-lysyl-glycine linkage

The incorporated MAL linkage in [64Cu]NODAGA-MAL-exendin-4 was unable to reduce kidney radioactivity levels, compared to [64Cu]NODAGA-exendin-4. The applicability of metabolizable linkages in the design of kidney-saving exendin-4 analogs requires further investigation.