TGW211 for Click-Cleavable Imaging in HER2-Positive Cancers.

\[111In\]In-DOTA-TCO-trastuzumab is a chemically cleavable \[111In\]In-labeled trastuzumab conjugate that is administered first to the patient, it accumulates in HER2-positive tumors and internalizes in HER2-expressing tumor cells.

TRG001 is a small molecule tetrazine trigger that reacts with \[111In\]In-TGW211-DC in blood and extracellular space thus releasing a fast clearing \[111In\]In-DOTA containing fragment which is rapidly eliminated via the kidney. Because of its non-cell permeable nature, TRG001 does not reach \[111In\]In-TGW211-DC inside tumor cells and therefore the radioactivity inside tumor cells is retained by the tumor.