A preliminary clinical trial to evaluate 64Cu-NOTA-Trastuzumab as a positron emission tomography imaging agent in patients with breast cancer

Background: The purpose of this study was to evaluate both the biodistribution and safety of Cu-64-1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA)-Trastuzumab, a novel Cu-64-labeled positron emission tomography (PET) tracer for human epidermal growth factor receptor 2 (HER2) in patients with breast cancer. Methods: PET images at 1, 24, and 48 h after 296 MBq of Cu-64-NOTA-Trastuzumab injection were obtained from seven patients with breast cancer. Both the primary tumors' and metastatic lesions' maximum standardized uptake value (SUVmax) was evaluated. The mean SUVmax (SUVmean) was evaluated in the other organs, including the blood pool, liver, kidney, muscle, spleen, bladder, and the lungs, as well as the bones. Moreover, the internal radiation dosimetry was calculated using the OLINDA/EXM software. Safety was assessed based on feedback regarding adverse reactions and safety-related issues within 1 month after Cu-64-NOTA-Trastuzumab administration. Results: Cu-64-NOTA-Trastuzumab PET images showed that the overall SUVmean values in each organ negatively correlated with time. The liver's average SUVmean values were measured at 5.3 +/- 0.7, 4.8 +/- 0.6, and 4.4 +/- 0.5 on 1 h, 24 h, and 48 h after injection, respectively. The average SUVmean blood values were measured at 13.1 +/- 0.9, 9.1 +/- 1.2, and 7.1 +/- 1.9 on 1 h, 24 h, and 48 h after injection, respectively. The SUVmax of HER2-positive tumors was relatively higher than HER2-negative tumors (8.6 +/- 5.1 and 5.2 +/- 2.8 on 48 h after injection, respectively). Tumor-to-background ratios were higher in the HER2-positive tumors than in the HER2-negative tumors. No adverse events related to Cu-64-NOTA-Trastuzumab were reported. The calculated effective dose with a 296 MBq injection of Cu-64-NOTA-Trastuzumab was 2.96 mSv. The highest absorbed dose was observed in the liver (0.076 mGy/MBq), followed by the spleen (0.063 mGy/MBq), kidney (0.044 mGy/MBq), and heart wall (0.044 mGy/MBq). Conclusions: Cu-64-NOTA-Trastuzumab showed a specific uptake at the HER2-expressing tumors, thus making it a feasible and safe monitoring tool of HER2 tumor status in patients with breast cancer.

Automated summary

The Cu-64-NOTA-Trastuzumab PET images showed specific uptake in HER2-expressing tumors, providing a feasible and safe monitoring tool for HER2 tumor status in patients with breast cancer.