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J Nucl Med. 2019 Jan;60(1):26-33. doi: 10.2967/jnumed.118.210294. Epub 2018 May 18.

Development of 64Cu-NOTA-Trastuzumab for HER2 Targeting: A Radiopharmaceutical with Improved Pharmacokinetics for Human Studies.

Author information

1
Division of RI-Convergence Research, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea; and.
2
Division of RI-Convergence Research, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea; and kang2325@kirams.re.kr.
3
Department of Radiology, University of California San Francisco School of Medicine, San Francisco, California kang2325@kirams.re.kr.

Abstract

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 (>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.

KEYWORDS:

64Cu-NOTA-trastuzumab; HER2; absorbed dose; patient selection; treatment response

PMID:
29777007
DOI:
10.2967/jnumed.118.210294

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