Application of an electrochemiluminescence assay for quantification of E6011, an antifractalkine monoclonal antibody, to pharmacokinetic studies in monkeys and humans.

BACKGROUND: E6011, a humanized antifractalkine monoclonal antibody, is under development for the treatment of various inflammatory diseases, such as rheumatoid arthritis. A reproducible assay method has been developed for the determination of E6011 in monkey and human serum by electrochemiluminescence (ECL) assay. METHODS: E6011 in serum was captured by fractalkine and detected by ruthenium-labeled rabbit anti-E6011 Fab polyclonal antibodies for ECL detection. E6011 in serum was quantifiable from 0.02 and 0.1 µg/mL in monkey and human serum, respectively, with minimum required dilution of 500. The method was then validated in accordance with bioanalytical guidelines. RESULTS: Accuracy and precision of quality control samples at five concentrations in intra- and interbatch reproducibility demonstrated that relative error and relative standard deviation were within acceptable criteria. Recovery of E6011 was 92.9%-121.7% and 85.0%-109.3% in humans and monkeys. Dilution integrity, no prozone effects, and no impacts by antigen were also ensured. Parallelism was also confirmed using incurred clinical sample analysis. Various types of stability were assessed, which confirmed that E6011 in serum was stable for 367 and 735 days in monkey and human sera, respectively, under frozen conditions. CONCLUSION: The developed method was successfully applied supporting pharmacokinetic studies in monkeys and humans.

Amelioration of Tumor-promoting Microenvironment via Vascular Remodeling and CAF Suppression Using E7130: Biomarker Analysis by Multimodal Imaging Modalities.

E7130 is a novel anticancer agent created from total synthetic study of the natural compound norhalichondrin B. In addition to inhibiting microtubule dynamics, E7130 also ameliorates tumor-promoting aspects of the tumor microenvironment (TME) by suppressing cancer-associated fibroblasts (CAF) and promoting remodeling of tumor vasculature. Here, we demonstrate TME amelioration by E7130 using multi-imaging modalities, including multiplexed mass cytometry [cytometry by time-of-flight (CyTOF)] analysis, multiplex IHC analysis, and MRI. Experimental solid tumors characterized by large numbers of CAFs in TME were treated with E7130. E7130 suppressed LAP-TGFß1 production, a precursor of TGFß1, in CAFs but not in cancer cells; an effect that was accompanied by a reduction of circulating TGFß1 in plasma. To our best knowledge, this is the first report to show a reduction of TGFß1 production in TME. Furthermore, multiplex IHC analysis revealed reduced cellularity and increased TUNEL-positive apoptotic cells in E7130-treated xenografts. Increased microvessel density (MVD) and collagen IV (Col IV), an extracellular matrix (ECM) component associated with endothelial cells, were also observed in the TME, and plasma Col IV levels were also increased by E7130 treatment. MRI revealed increased accumulation of a contrast agent in xenografts. Moreover, diffusion-weighted MRI after E7130 treatment indicated reduction of tumor cellularity and interstitial fluid pressure. Overall, our findings strongly support the mechanism of action that E7130 alters the TME in therapeutically beneficial ways. Importantly, from a translational perspective, our data demonstrated MRI as a noninvasive biomarker to detect TME amelioration by E7130, supported by consistent changes in plasma biomarkers.

Quantification of anti-drug antibodies against E6011, an anti-fractalkine monoclonal antibody, in monkey and human serum, by an electrochemiluminescence assay.

E6011, a humanized anti-fractalkine monoclonal antibody, is under development for the treatment of various inflammatory diseases, such as rheumatoid arthritis. Therapeutic antibodies may induce production of anti-drug antibodies (ADA) that may deteriorate efficacy and/or enhance immunogenic reaction. It is important to have an ADA assay to understand the characteristics of biotherapeutics under development. A simple and reproducible assay has thus been developed for the determination of ADA against E6011 in monkey and human serum by electrochemiluminescence (ECL) detection. An immune-complex of biotinylated E6011, ADA, and ruthenium-labeled E6011 was attached to avidin-coated wells for ECL signal detection. Screening and confirmatory cutpoints were determined to judge negative or positive ADA. Sensitivity of ADA was 1.61 and 1.34 ng/mL in monkey and human serum, respectively. Accuracy and precision of the assay were within ±20% and 20%, respectively. Drug tolerance of the assay in monkey and human sera was ensured up to 100 and 1000 µg/mL E6011 at the surrogate ADA levels of 1 and 4 µg/mL, respectively. The developed assay was successfully applied to ADA quantification in monkeys and humans in support of immunogenicity assessments.

Pre-clinical characterisation of E2814, a high-affinity antibody targeting the microtubule-binding repeat domain of tau for passive immunotherapy in Alzheimer's disease.

Tau deposition in the brain is a pathological hallmark of many neurodegenerative disorders, including Alzheimer's disease (AD). During the course of these tauopathies, tau spreads throughout the brain via synaptically-connected pathways. Such propagation of pathology is thought to be mediated by tau species ("seeds") containing the microtubule binding region (MTBR) composed of either three repeat (3R) or four repeat (4R) isoforms. The tau MTBR also forms the core of the neuropathological filaments identified in AD brain and other tauopathies. Multiple approaches are being taken to limit tau pathology, including immunotherapy with anti-tau antibodies. Given its key structural role within fibrils, specifically targetting the MTBR with a therapeutic antibody to inhibit tau seeding and aggregation may be a promising strategy to provide disease-modifying treatment for AD and other tauopathies. Therefore, a monoclonal antibody generating campaign was initiated with focus on the MTBR. Herein we describe the pre-clinical generation and characterisation of E2814, a humanised, high affinity, IgG1 antibody recognising the tau MTBR. E2814 and its murine precursor, 7G6, as revealed by epitope mapping, are antibodies bi-epitopic for 4R and mono-epitopic for 3R tau isoforms because they bind to sequence motif HVPGG. Functionally, both antibodies inhibited tau aggregation in vitro. They also immunodepleted a variety of MTBR-containing tau protein species. In an in vivo model of tau seeding and transmission, attenuation of deposition of sarkosyl-insoluble tau in brain could also be observed in response to antibody treatment. In AD brain, E2814 bound different types of tau filaments as shown by immunogold labelling and recognised pathological tau structures by immunohistochemical staining. Tau fragments containing HVPGG epitopes were also found to be elevated in AD brain compared to PSP or control. Taken together, the data reported here have led to E2814 being proposed for clinical development.

Elevation of serum KL-6 glycoprotein or surfactant protein-D in adult T-cell leukemia with distinct pulmonary complications.

Patients with hematological malignancies frequently suffer from lung diseases as a complication. However, it is difficult to discriminate leukemic invasion into the lung from infectious pulmonary complications. The serum level of Krebs von den Lungen-6 (KL-6), which is a mucin-like glycoprotein, is increased in more than 70% of patients with interstitial pneumonia. Surfactant protein-D (SP-D) is produced mainly in the lung by alveolar type II and bronchiolar epithelial cells and is a useful serum marker for interstitial pneumonia. We therefore measured the levels of KL-6 and SP-D in sera from 128 patients (76 males and 52 females, mean age: 59 years) with hematological malignancies, including adult T-cell leukemia (ATL). Overall, the increase in KL-6 or SP-D, above each cut-off value (500 U/ml for KL-6 and 110 ng/ml for SP-D), was detected in 11 patients (8.6%) or 10 patients (7.8%), respectively. In contrast, among 67 ATL patients, 15 patients had high serum levels of KL-6 and/or SP-D; both were elevated in 2 patients, only KL-6 was elevated in 6 patients and only SP-D was elevated in 7 patients. Thus, serum KL-6 and SP-D appear to be elevated in a mutually exclusive manner in ATL. Indeed, high serum levels of KL-6 were closely related to the stage of ATL, while the serum SP-D was elevated in ATL patients with pulmonary infection. In conclusion, the combined measurement of KL-6 and SP-D in ATL may become a useful means to discriminate leukemic pulmonary lesions from infectious pulmonary complications.

Pharmacokinetics, Pharmacodynamics, and Safety of E6011, a Novel Humanized Antifractalkine (CX3CL1) Monoclonal Antibody: A Randomized, Double-Blind, Placebo-Controlled Single-Ascending-Dose Study.

E6011 is a novel humanized antifractalkine (FKN) monoclonal antibody being developed as a therapeutic target for Crohn's disease, rheumatoid arthritis, and primary biliary cholangitis. This study was a randomized, double-blind, placebo-controlled single-ascending-dose study of intravenous administration of E6011 (0.0006-10 mg/kg) in healthy Japanese adult men (n = 64). The starting dose was the minimum anticipated biological effect level (MABEL). MABEL was estimated by extrapolating results of a pharmacokinetic/pharmacodynamic (PK/PD) model relating E6011 exposure and suppression of free soluble FKN using data obtained from cynomolgus monkeys. Safety assessments consisted of monitoring and recording adverse events, laboratory tests, vital signs, intensive electrocardiograms, and chest x-rays. Blood samples to determine PK, PD (serum total FKN concentration), and serum anti-E6011 antibody were collected. Noncompartmental analysis was used to derive PK parameters. Single intravenous infusions of E6011 were safe and well tolerated in healthy subjects. Serum E6011 concentrations showed triphasic elimination. An increase in serum total FKN concentration was observed, confirming target engagement. The dose strategy for patient studies is to select regimens that will attain a minimum serum E6011 exposure of 10 µg/mL, identified as the minimum concentration needed to saturate the target-mediated elimination pathway. Model-based drug development from preclinical stage was successful in identifying dose regimens for clinical testing.

Elucidation of the statistical factors that influence anti-drug antibody cut point setting through a multi-laboratory study.

Aim: Appropriateness of anti-drug antibody (ADA) assay is critical for immunogenicity assessment of biopharmaceuticals. Although cut point setting in ADA assay has a large impact on the results, a standard statistical approach for its setting has not been well established. Methodology: In this multi-laboratory study, to elucidate factors influencing the cut point setting, we compared the statistical approaches and calculated cut points for multiple datasets of ADA assays using the individual procedure employed at each laboratory. Conclusion: We showed that outlier exclusion, false-positive rate and investigating data distribution have the greatest impact on both screening and confirmatory cut points. Our results would be useful for industry researchers and regulators engaged in immunogenicity assessment of biopharmaceuticals.

Immunogenicity of therapeutic protein products: current considerations for anti-drug antibody assay in Japan.

Immunogenicity assessment is an important issue for ensuring the safety and efficacy of therapeutic protein products. Although the reliability of the anti-drug antibody (ADA) assay is one of the key points, there are some difficulties in assessing its validity because the analytes are polyclonal antibodies with variable and unknown characteristics. To elucidate the points to consider for the ADA assay, a Japanese research group was established that discusses the issues raised on the immunogenicity assessment. In this review, we first introduce the current situation regarding the development and immunogenicity assessment of therapeutic protein products in Japan. We then present our current view and recommendations on the ADA assay by considering its unique features.

Cytochrome c and tumor necrosis factor-alpha values in serum and cerebrospinal fluid of patients with influenza-associated encephalopathy.

Cytochrome c and tumor necrosis factor-alpha concentrations were measured in serum and cerebrospinal fluid samples from 10 patients with influenza-associated encephalopathy. In the acute exacerbation phase, serum tumor necrosis factor-alpha and cytochrome c values were high in patients with a poor prognosis. In the convalescent phase, cerebrospinal fluid cytochrome c values increased remarkably in patients with subsequent brain atrophy.

Cytochrome c is a possible new marker for fulminant hepatitis in humans.

BACKGROUND: Cytochrome c is known as a substance related to apoptosis. We investigated serum cytochrome c levels in patients with fulminant hepatitis (FH) compared with these levels in patients with acute or chronic liver diseases. METHODS: Serum cytochrome c was measured by an electrochemiluminescence immunoassay (ECLIA) method. The numbers of patients were as follows: fulminant hepatitis (FH; n = 15), acute hepatitis (AH; n = 12), chronic hepatitis (CH; n = 30), chronic hepatitis with acute aggravation (CHA; n = 6), liver cirrhosis (LC; n = 30), hepatocellular carcinoma (HCC; n = 30), and healthy volunteers (controls; n = 9). RESULTS: The serum cytochrome c level in FH was 10 686 +/- 7787 pg/ml, with a significant difference (P < 0.01) compared to levels in the other groups. In the FH patients, the serum cytochrome c level was significantly correlated to serum mitochondria (m)-GOT, hepatocyte growth factor (HGF), aspartate aminotransferase (AST), lactic dehydrogenase (LDH), and alkaline phosphatase (ALP), and it was negatively correlated to serum alpha-fetoprotein (AFP), and total bilirubin (T.Bil.) The serum cytochrome c level seemed to parallel the severity of hepatic coma. Immunohistochemical study indicated TdT mediated dUTP nick end labeling (TUNEL)-positive cells in the livers of patients with FH. CONCLUSIONS: These results suggest that serum cytochrome c may be a possible new marker for acute liver failure.

A novel role of serum cytochrome c as a tumor marker in patients with operable cancer.

PURPOSE: This study aimed to evaluate serum cytochrome c (cyto-c) levels as a novel role of tumor marker in patients with operable malignant tumors. METHODS: Serum cyto-c levels and lactate dehydrogenase (LD) activity were measured in a total of 257 cases (232 malignant and 25 benign). To identify the relationship between serum cyto-c and current tumor markers, six variables, such as gender, age, invasion, lymph node metastasis, distant metastasis, and LD, were analyzed by uni- and multivariate regression analysis methods. The test performance of serum cyto-c for the prediction of malignant behavior was evaluated by receiver operating characteristic (ROC) curves. RESULTS: The serum cyto-c level was significantly higher in patients with malignant tumors than patients with benign tumors (20.6 vs. 15.5 ng/mL; P = 0.017, Mann-Whitney U test). No difference in the levels among subtypes of cancer was found, indicating that the change in serum cyto-c levels reflect cancer individually and not specific subtypes of cancer. The survival in patients with serum cyto-c levels over 40 ng/mL was poor (Kaplan-Meier test, P < 0.0001, Hazard ratio 16.76, 95% confidential interval 4.45-63.04). Multiple linear regression analyses disclosed the close association of serum cyto-c levels with invasion (P = 0.0004), metastasis (P = 0.0262) except for regional lymph node metastasis, and activity of serum LD (P < 0.0001), all of which are well known to represent malignant behavior. Conversely, the measurement of serum cyto-c was verified to have excellent diagnostic accuracy of 0.802 and 0.781 for the detection of invasion and metastasis (the area under curves of the constructed ROCs). CONCLUSION: Serum cyto-c is a potent tumor marker as a predictor for malignant potential in cancers.