111In-HE3-G3

111In-HE3-G3 is a radiolabeled designed ankyrin repeat protein (DARPin) developed for the *in vivo* SPECT imaging of HER2-expressing tumors, such as breast and ovarian cancers. It consists of the G3 DARPin, which binds to human epidermal growth factor receptor 2 (HER2) with picomolar affinity at an epitope distinct from that of trastuzumab. The construct features an N-terminal histidine-glutamate (HE)3 tag, which reduces background liver uptake and facilitates purification, and is conjugated to the chelator DOTA at a C-terminal cysteine to enable labeling with the gamma-emitting radioisotope Indium-111 (111In). Developed by researchers at University College London, Barts Cancer Institute, and the University of Zurich, 111In-HE3-G3 has demonstrated high tumor-to-blood ratios and rapid clearance in preclinical models, making it a promising candidate for the non-invasive assessment of HER2 status.

Other names

111In-(HE)3-G3111In-DOTA-(HE)3-G3111In-DOTA-HE3-G3indium-111 (HE)3-G3indium-111 HE3-G3indium111 HE3-G3indium 111 HE3-G3