Evaluation of 64Cu-Labeled New Anti-EGFR Antibody NCAB001 with Intraperitoneal Injection for Early PET Diagnosis of Pancreatic Cancer in Orthotopic Tumor-Xenografted Mice and Nonhuman Primates

Abstract

Objectives: To improve the prognosis of pancreatic cancer, new imaging methods to identify tumor lesions at a size of <1 cm are urgently needed. To approach this clinical issue, we developed a new method to detect small tumor lesions in the pancreas (≥3 mm) by positron emission tomography (PET) using an intraperitoneally (ip)-administered 64Cu-labeled new anti-epidermal growth factor receptor (EGFR) antibody (encoded as NCAB001), called 64Cu-NCAB001 ipPET. Methods: NCAB001 was manufactured under cGMP conditions and labeled with 64Cu. The radiochemical and biological properties of 64Cu-NCAB001 were evaluated. Tumor uptake of an ip-administered 64Cu-NCAB001 in mice with orthotopic pancreatic tumor xPA1-DC xenografts was also evaluated. Pharmacokinetics and radiation dosimetry were examined using PET images acquired after the ip administration of 64Cu-NCAB001 into cynomolgus monkeys with pharmacologic safety monitoring. Results: Radio-chromatography, cell-binding assays, and biodistribution of 64Cu-NCAB001 in mice were identical to those of our previous data with clinically available cetuximab. Small tumor lesions in the pancreas (≥3 mm) of mice could be identified by 64Cu-NCAB001 ipPET. The ip administration of 64Cu-NCAB001 into monkeys was safely conducted using ultrasound imaging. PET images in monkeys showed that ip-administered 64Cu-NCAB001 was distributed throughout the intraperitoneal cavity for up to 6 h and cleared thereafter. Most of the radioactivity was distributed in the liver and the large intestine. The radioactivity around the pancreas became negligible 24 h after administration. The estimated human effective dose was 0.0174 mSv/MBq. Conclusion: Our data support the initiation of clinical trials of 64Cu-NCAB001 ipPET to transfer this promising tool for the early diagnosis of pancreatic cancers.

Characterization and Stabilization of a New 64Cu-Labeled Anti-EGFR Antibody NCAB001 for the Early Detection of Pancreatic Cancer with Positron Emission Tomography

“…To separate the free [ 64 Cu] copper ion from 64 Cu-NCAB001, a silica gel 60 plate (Merck Millipore, Burlington, MA, USA) and a mobile phase of methanol:water (80:20, v/v) were used. The retention factor of 64 Cu-NCAB001 on TLC were 0-0.1, which is identical to that of the reference standard cetuximab [13]. The retention factor of the radio-chemical impurities of 64 Cu-NCAB001 on TLC were identical to that of the free [ 64 Cu] copper ion (0.8).…”

“…The anti-EGFR antibody NCAB001 was manufactured under current good manufacturing practice (cGMP) conditions at Mycenax Biotech Inc. (Jhunan, Taiwan) [13]. For antibody conjugation, a NCAB001 solution (2 mg/mL in 50 mM borate buffer, pH 8.5) was prepared by buffer exchange with a Vivaspin ultrafiltration device (Sartorius, Göttingen, Germany).…”

“…We have labeled NCAB001 with 64 Cu and demonstrated that 64 Cu-NCAB001 is protein-chemically, radiochemically, and biochemically comparable to 64 Cu-cetuximab [13]. In addition, the ip-administration of 64 Cu-NCAB001 to monkeys was safely conducted using ultrasound imaging [13]. On the basis of these promising findings, we have initiated the preclinical and pharmaceutical development of 64 Cu-NCAB001 for the early diagnosis of pancreatic cancer with PET.…”

“…In contrast, we could not detect lesions ≥ 3 mm in diameter after intravenous (iv) administration of 64 Cu-cetuximab or iv/ip administration of 18 F-fluorodeoxyglucose ( 18 F-FDG). To accelerate the development of this approach into clinical practice, we have established the efficient and sustainable manufacturing of a new anti-EGFR antibody encoded as NCAB001 (with the same amino acid sequence as cetuximab but different post-translational modifications such as the N-glycan profile) [13]. We used Chinese hamster ovary (CHO) cells instead of murine hybridoma cells (Sp2/O-Ag14), which has been used for the manufacturing of cetuximab [14], as the yield in CHO cells is higher than that in Sp2/O cells [15].…”

“…We used Chinese hamster ovary (CHO) cells instead of murine hybridoma cells (Sp2/O-Ag14), which has been used for the manufacturing of cetuximab [14], as the yield in CHO cells is higher than that in Sp2/O cells [15]. We have labeled NCAB001 with 64 Cu and demonstrated that 64 Cu-NCAB001 is protein-chemically, radiochemically, and biochemically comparable to 64 Cu-cetuximab [13]. In addition, the ip-administration of 64 Cu-NCAB001 to monkeys was safely conducted using ultrasound imaging [13].…”