Process to Remove the Size Variants Contained in the Antibody-Chelator Complex PCTA-NCAB001 for Radiolabeling with Copper-64.

Understanding the physicochemical properties of antibody-drug conjugates is critical to assess their quality at manufacturing and monitor them during subsequent storage. For radiometal-antibody complexes, it is important to control the properties of the antibody-chelator conjugate to maintain the quality of the final product. We have been developing 64Cu-labeled anti-epidermal growth factor receptor antibody NCAB001 (64Cu-NCAB001) for the early diagnosis and therapy of pancreatic cancer with positron-emission tomography. Here, we characterized the larger size variants contained in the antibody-chelator conjugate PCTA-NCAB001 by multi-angle light scattering coupled with size-exclusion chromatography. Secondly, we developed a chromatographic method to remove these size variants. Lastly, we demonstrated the stability of PCTA-NCAB001 after the removal of size variants. Dimer and oligomers were identified in PCTA-NCAB001. These larger size variants, together with some smaller size variants, could be removed by hydrophobic interaction chromatography. The PCTA-NCAB001 product, after the removal of these size variants, could be stored at 4 °C for six months. The methods developed here can be applied to assure the quality of PCTA-NCAB001 and other antibody-drug conjugates to facilitate the development of antibody-radiometal conjugates for positron-emission tomography and radioimmunotherapy of malignant cancers.

Preclinical Safety Evaluation of Intraperitoneally Administered Cu-Conjugated Anti-EGFR Antibody NCAB001 for the Early Diagnosis of Pancreatic Cancer Using PET.

Detecting tumor lesions <1 cm in size using current imaging methods remains a clinical challenge, especially in pancreatic cancer. Previously, we developed a method to identify pancreatic tumor lesions ≥3 mm using positron emission tomography (PET) with an intraperitoneally administered 64Cu-labeled anti-epidermal growth factor receptor (EGFR) antibody (64Cu-NCAB001 ipPET). Here, we conducted an extended single-dose toxicity study of 64Cu-NCAB001 ipPET in mice based on approach 1 of the current ICH M3 [R2] guideline, as our new drug formulation contains 45 µg of the antibody. We used NCAB001 labeled with stable copper isotope instead of 64Cu. The total content of size variants was approximately 6.0% throughout the study. The relative binding potency of Cu-NCAB001 to recombinant human EGFR was comparable to that of cetuximab. The general and neurological toxicities of Cu-NCAB001 ipPET at 62.5 or 625 µg/kg were assessed in mice. The no-observed-adverse-effect level of Cu-NCAB001 was 625 µg/kg, a dose approximately 1000-fold higher at the µg/kg level than the dose of 64Cu-NCAB001 in our formulation (45 µg). The size variants did not affect the safety of the formulation. Therefore, clinical studies on the efficacy of 64Cu-NCAB001 ipPET for early detection of pancreatic cancer using PET imaging can be safely conducted.

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.

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.

Early diagnosis of pancreatic cancer using current imaging modalities remains challenging. We have developed a new approach to identify tumor lesions ≥ 3 mm in the pancreas by positron emission tomography (PET) with a new intraperitoneally administered 64Cu-labeled anti-epidermal growth factor receptor (EGFR) antibody (encoded as NCAB001), called 64Cu-NCAB001 ipPET. Generally, in clinical research, a radiometal-antibody complex must be prepared immediately before use at the imaging site. To make 64Cu-NCAB001 ipPET available to daily clinical practices in a sustainable way, the NCAB001-chelator conjugate and 64Cu-NCAB001 must be characterized and stabilized. NCAB001 was manufactured under cGMP conditions. NCAB001 was conjugated with a bifunctional chelator (p-SCN-Bn-PCTA), and the antibody-chelator conjugate (PCTA-NCAB001) was characterized by LC/MS and ELISA. Thereafter, to effectively manufacture 64Cu-NCAB001, we developed a new formulation to stabilize PCTA-NCAB001 and 64Cu-NCAB001. An average of three PCTA chelators were conjugated per molecule of NCAB001. The relative binding potency of PCTA-NCAB001 was comparable to cetuximab. The formulation consisting of acetate buffer, glycine, and polysorbate-80 stabilized PCTA-NCAB001 for a year-long storage. Additionally, this formulation enabled the stabilization of 64Cu-NCAB001 for up to 24 h after radiolabeling with a sufficient radioactivity concentration for clinical use. These results may accelerate the future use of 64Cu-NCAB001 ipPET in clinical settings for the early diagnosis and treatment of pancreatic cancer.

Anti-VEGFR2 Antibody-modified Micelle for Triggered Drug Delivery and Effective Therapy of Choroidal Neovascularization.

OBJECTIVE: This study aimed to examine whether DC101 (anti-VEGFR2 antibody)- modified micelles have applications as novel drug delivery devices, which allow small molecule antiangiogenic agents to deliver to angiogenic sites on a murine laser-induced choroidal neovascularization (CNV) model. MATERIALS AND METHODS: CNV was induced by photocoagulation on the unilateral eye of each mouse under anesthesia. Immediately after laser coagulation, E7974-loaded DC101-modified micelles and motesanib-loaded DC101-modified micelles were intravitreally administrated. Two weeks after photocoagulation, CNV was visualized using fluorescein-conjugated dextran (MW=2,000 kDa), and the CNV area was measured in retinal pigment epithelium (RPE)-choroidal flat mounts. RESULTS: Intravitreal administration of both DC101-modified micelles loaded with E7974 at 2 µM and motesanib at 2 µM significantly reduced CNV area in the murine laser-induced CNV model at a clearly lower concentration than the effective dose of each agent. CONCLUSION: These results suggest that DC101-modified micelle might be effective drug carrier system for treating CNV and other ocular angiogenic diseases.

NC-6004 Phase I study in combination with gemcitabine for advanced solid tumors and population PK/PD analysis.

OBJECTIVES: This study was an open-label phase I study to confirm the safety and tolerability of NC-6004 in combination with gemcitabine in Japanese patients with advanced solid tumors and to assess the PK effects of NC-6004 monotherapy. METHODS: This phase I study used a 3 + 3 design to determine the maximum tolerated dose (MTD) and recommended dose of NC-6004 combined with gemcitabine. Safety and pharmacokinetics were assessed. The administration of NC-6004 alone was started at 60 mg/m2 every treatment cycle (21 days per cycle). From the second through eighth cycles, patients received NC-6004 in combination with 1000 mg/m2 of gemcitabine that was administered on day 1 and day 8 of each cycle, except for the first treatment cycle. RESULTS: Twelve patients with advanced solid tumors received 60 or 90 mg/m2 NC-6004. Both MTD and RD were determined to be 90 mg/m2. The most common drug-related adverse events were neutrophil decrease (66.7%) and white blood cell count decrease (41.7%). Population pharmacokinetic (PK) analysis revealed that NC-6004 PK profile in Japanese study was not significantly different from that in a previous Caucasian study. CONCLUSIONS: Both MTD and RD of NC-6004 were determined to be 90 mg/m2. The pharmacodynamic (PD) model well explained the time course of estimated glomerular filtration rate (eGFR) and amplitude of decrease in eGFR. The decrease in eGFR appeared to reach saturation at >100 mg/m2 with NC-6004. Estimated probability of acute kidney injury on this PK/PD simulation was 30% with NC-6004 and 70% with cisplatin, which may better explain the renal toxicity profile.

Increased phosphorylation of Akt in triple-negative breast cancers.

Cells from breast cancers lacking hormone receptors (estrogen receptor [ER], progesterone receptor [PgR]) and human epidermal growth factor receptor (HER) 2 strongly express the cell proliferation marker Ki-67. However, the mechanisms of and stimulus signals involved in cell proliferation of this type of breast cancer are not well understood. The aim of the present study was to examine the characteristics of signal transduction in triple-negative (ER-, PgR-, and HER2-negative) breast cancers. For 44 tumor samples, western blotting analysis was conducted to examine the phosphorylation of HER2, external signal-regulated kinase (ERK)1 and -2 and Akt, and the immunohistochemical phenotypes of the samples with respect to ER and HER2 were also assessed. Phosphorylation of HER2 was detected in 4 of 15 immunohistochemically HER2-positive tumor samples (26.7%). ERK1/2 was more highly phosphorylated in triple-negative breast cancers. Phosphorylation of Akt kinase was significantly higher in triple-negative breast cancers. Triple-negative breast cancers are characterized by increased phosphorylation of Akt kinase. In the present study, we found for the first time that there is a population with a significantly activated Akt pathway in this type of breast cancer.

Novel HER2 selective tyrosine kinase inhibitor, TAK-165, inhibits bladder, kidney and androgen-independent prostate cancer in vitro and in vivo.

PURPOSE: TAK-165 is a new potent inhibitor of human epidermal growth factor receptor 2 (HER2) tyrosine kinase. Several reports suggest HER2 expression in bladder cancer, renal cell carcinoma (RCC) and androgen-independent prostate cancer. We therefore investigated the antitumor effect of TAK-165 on these urological cancer cells. MATERIALS AND METHODS: Western blot analysis was performed to confirm HER2 expression in cell lines. To study in vitro efficacy, cells were treated with TAK-165 at various concentrations for 72 h and then counted using a hemocytometer. Then the IC50 value was calculated. In the xenograft model, after the tumor reached 200-300 mm3 in volume, mice were orally administered TAK-165 10 mg/kg per day or 20 mg/kg per day or saline for 14 consecutive days (n=6-8). RESULTS: HER2 expression was observed in HT1376, UMUC3, T24 (bladder), ACHN (kidney), DU145, LNCaP, LN-REC4 (prostate), although the expression level in these cells was weak compared with BT474 (a breast cancer cell line which expresses HER2 strongly). IC50 was varied from 0.09 to greater than 25 micromol/L in the bladder cancer cell line. ACHN cells were less sensitive in vitro. The prostate cancer cell lines studied were all sensitive (IC50 0.053-4.62 micromol/L). In the xenograft model, treatment with TAK-165 significantly inhibited growth of UMUC-3, ACHN, and LN-REC4. The antitumor effect (T/C [%]=growth of TAK-165 treated tumor/average growth of control tumorx100) after 14 days treatment were 22.9%, 26.0%, and 26.5% in UMUC3, ACHN and LN-REC4, respectively. CONCLUSIONS: TAK-165 may be a hopeful new agent for bladder, kidney and androgen-independent prostate cancer.