PT - JOURNAL ARTICLE AU - Sang-Keun Woo AU - Su Jin Jang AU - Min-Jung Seo AU - Ju Hui Park AU - Byoung Soo Kim AU - Eun Jung Kim AU - Yong Jin Lee AU - Tae Sup Lee AU - Gwang Il An AU - In Ho Song AU - Youngho Seo AU - Kwang Il Kim AU - Joo Hyun Kang TI - Development of <sup>64</sup>Cu-NOTA-Trastuzumab for HER2 Targeting: A Radiopharmaceutical with Improved Pharmacokinetics for Human Studies AID - 10.2967/jnumed.118.210294 DP - 2019 Jan 01 TA - Journal of Nuclear Medicine PG - 26--33 VI - 60 IP - 1 4099 - http://jnm.snmjournals.org/content/60/1/26.short 4100 - http://jnm.snmjournals.org/content/60/1/26.full SO - J Nucl Med2019 Jan 01; 60 AB - The purpose of this study was to develop 64Cu-labeled trastuzumab with improved pharmacokinetics for human epidermal growth factor receptor 2 (HER2). Methods: Trastuzumab was conjugated with SCN-Bn-NOTA and radiolabeled with 64Cu. Serum stability and immunoreactivity of 64Cu-NOTA-trastuzumab were tested. Small-animal PET imaging and biodistribution studies were performed in a HER2-positive breast cancer xenograft model (BT-474). The internal dosimetry for experimental animals was determined using the image-based approach with the Monte Carlo N-particle code. Results: 64Cu-NOTA-trastuzumab was prepared with high radiolabeling yield and radiochemical purity (&gt;98%) and showed high stability in serum and good immunoreactivity. Uptake of 64Cu-NOTA-trastuzumab was highest at 48 h after injection as determined by PET imaging and biodistribution results in BT-474 tumors. The blood radioactivity concentrations of 64Cu-NOTA-trastuzumab decreased biexponentially with time in both mice with and mice without BT-474 tumor xenografts. The calculated absorbed dose of 64Cu-NOTA-trastuzumab was 0.048 mGy/MBq for the heart, 0.079 mGy/MBq for the liver, and 0.047 mGy/MBq for the spleen. Conclusion: 64Cu-NOTA-trastuzumab was effectively targeted to the HER2-expressing tumor in vitro and in vivo, and it exhibited a relatively low absorbed dose due to a short residence time. Therefore, 64Cu-NOTA-trastuzumab could be applied to select the right patients and right timing for HER2 therapy, to monitor the treatment response after HER2-targeted therapy, and to detect distal or metastatic spread.