99mTc-MIRC208

99mTc-MIRC208 is a radiopharmaceutical composed of a single-domain antibody fragment (VHH or nanobody) that specifically targets the human epidermal growth factor receptor 2 (HER2). The VHH was derived by immunizing alpaca with human HER2 protein and then site-specifically labeled with technetium-99m (99mTc), a gamma-emitting radioisotope suitable for SPECT/CT imaging. 99mTc-MIRC208 binds to an epitope on HER2 that overlaps with the binding site of trastuzumab, thus it competes directly with trastuzumab for HER2 binding. This property allows it to noninvasively assess HER2 accessibility and predict response to trastuzumab therapy in patients with HER2-positive cancers. Preclinical studies demonstrated specific uptake in HER2-positive tumors but not in HER2-negative tumors, and early clinical studies showed clear visualization of primary and metastatic lesions in patients with HER2-positive breast cancer[1][2][3].

Other names

technetium Tc-99m MIRC208