[99mTc]Tc-(HE)3-G3

[99mTc]Tc-(HE)3-G3 is a radiopharmaceutical molecular imaging agent based on a designed ankyrin repeat protein (DARPin), specifically the G3 variant, which binds with high affinity to human epidermal growth factor receptor type 2 (HER2). The molecule is labeled with technetium-99m using a peptide-based chelator His-Glu-His-Glu-His-Glu ((HE)₃). It is used for non-invasive radionuclide imaging to discriminate between HER2-positive and HER2-negative tumors in breast cancer patients. Clinical studies have demonstrated its safety and ability to visualize both primary tumors and metastases in HER2-positive breast cancer. The agent enables stratification of patients for HER2-targeted therapies by providing clear SPECT/CT images within hours after intravenous injection. Its mechanism relies on specific binding to the extracellular domain of the HER2 receptor, allowing assessment of receptor status in vivo[1][7][5].

Other names

DARPin G3technetium-99m-labeled (HE)3-G399mTc-DARPin G3