Time filter

Source Type

GEORGETOWN, TX, United States

Zhong Z.D.,Amgen Inc. | Dinnogen S.,Amgen Inc. | Hokom M.,Amgen Inc. | Ray C.,Amgen Inc. | And 4 more authors.
Journal of Immunological Methods | Year: 2010

A well-designed anti-drug antibody (ADA) immunoassay is critical for appropriately monitoring the immunogenicity profile of a therapeutic protein during its development. AMG 386 is a peptide-Fc fusion protein that inhibits angiogenesis by preventing the interaction of angiopoietins with the Tie2 receptor. In bridging immunoassays for ADA, interference by the drug target, present in the assay sample, can result in false positive antibody detection. We used a statistical design-of-experiments approach to identify angiopoietin interference in bridging immunoassays of anti-AMG 386 antibodies. We also demonstrated that a high-affinity monoclonal antibody, directed against an epitope on angiopoietin that competes with AMG 386 binding, could inhibit the angiopoietin interference while preserving the detection of ADA. This report describes the development and validation of methodologies for evaluating and addressing drug target interference in bioanalytical assays that involve interactions between drug, ADA, immune complexes, and drug target. © 2010 Elsevier B.V.

Wang J.,Amgen Inc. | Nowatzke W.,Radix Biosolutions, Ltd | Ma M.,Amgen Inc.
Bioanalysis | Year: 2015

Specific guidelines on bioanalytical method validation for drug development support are recommended by regulatory agencies. Regarding stability assessment, US FDA states that 'Stability procedures should evaluate the stability of the analytes during sample collection and handling, after long-term (frozen at the intended storage temperature) and short-term (bench-top, room temperature) storage, and after going through freeze and thaw cycles and the analytical process'. Additional regulatory considerations are discussed including topics such as analyte and reagent stability. This article reviews the regulatory requirements as issued by the USA (FDA), Europe (EMA) and Japan (MHLW), for stability studies where bioanalytical methods are used to support drug development programs and summarizes the current industry standard for conducting stability studies when utilizing ligand-binding assays. © 2015 Future Science Ltd.

Almey A.,Concordia University at Montreal | Cannell E.,Concordia University at Montreal | Bertram K.,Concordia University at Montreal | Filardo E.,Radix Biosolutions, Ltd | And 3 more authors.
Endocrinology | Year: 2014

High plasma levels of estradiol (E2) are associated with use of a place memory system over a response memory system. We examined whether infusing estradiol into the medial prefrontal cortex (mPFC) or anterior cingulate cortex (AC) could affect memory system bias in female rats. We also examined the ultrastructural distribution of estrogen receptor (ER)-α, ERβ, and G protein-coupled estrogen receptor 1 (GPER1) in the mPFC of female rats as a mechanism for the behavioral effects of E2 in the mPFC. Each rat was infused bilaterally with either E2 (0.13 μg) or vehicle into the mPFC or AC. The majority of E2 mPFC rats used place memory. In contrast, the majority of mPFC vehicle rats and AC E2 or vehicle rats used response memory. These data show that mPFC E2 rapidly biases females to use place memory. Electron microscopic analysis demonstrated that ERα, ERβ, and GPER1 are localized in the mPFC, almost exclusively at extranuclear sites. This is the first time that GPER1 has been localized to the mPFC of rats and the first time that ERα and ERβ have been described at extranuclear sites in the rat mPFC. The majority of receptors were observed on axons and axon terminals, suggesting that estrogens alter presynaptic transmission in the mPFC. This provides a mechanism via which ERs could rapidly alter transmission in the mPFC to alter PFC-dependent behaviors, such as memory system bias. The discrete nature of immunolabeling for these membrane-associated ERs may explain the discrepancy in previous light microscopy studies. Copyright © 2014 by the Endocrine Society.

Ray C.A.,Radix Biosolutions, Ltd | Zhou L.,Amgen Inc. | Tsoi J.,Amgen Inc. | Uy L.,Amgen Inc. | And 7 more authors.
Journal of Pharmaceutical and Biomedical Analysis | Year: 2010

Outsourcing and multi-site testing has increased for ligand binding assays supporting protein therapeutic measurement. It is common to combine and compare data across studies with data from multiple bioanalytical sites. We designed a prospective study to determine the benefits of increasing control over the transfer process to improve ruggedness. The experiment involved the testing of 30 incurred samples at 3 stages with incremental laboratory harmonization in standard/quality controls and assay components: Stage I represented a transfer of a detailed protocol and critical reagents. Stage II, a single source of standards and quality controls were provided to each site. Stage III, standards and quality controls plus a ready-to-use kit were provided. The results indicated that all testing facilities failed agreement testing using the stage I procedure. The introduction of standards from a single source improved the agreement. The modification reduced variation by 33% compared to the stage I approach. There was no additional benefit when a packaged kit was provided. In conclusion, introduction of a single source of standards and quality controls reduced the inter-site component of variation and should allow for combinability of data. © 2010 Elsevier B.V.

Basile A.J.,Centers for Disease Control | Horiuchi K.,Centers for Disease Control | Panella A.J.,Centers for Disease Control | Laven J.,Centers for Disease Control | And 5 more authors.
PLoS ONE | Year: 2013

Serodiagnosis of arthropod-borne viruses (arboviruses) at the Division of Vector-Borne Diseases, CDC, employs a combination of individual enzyme-linked immunosorbent assays and microsphere immunoassays (MIAs) to test for IgM and IgG, followed by confirmatory plaque-reduction neutralization tests. Based upon the geographic origin of a sample, it may be tested concurrently for multiple arboviruses, which can be a cumbersome task. The advent of multiplexing represents an opportunity to streamline these types of assays; however, because serologic cross-reactivity of the arboviral antigens often confounds results, it is of interest to employ data analysis methods that address this issue. Here, we constructed 13-virus multiplexed IgM and IgG MIAs that included internal and external controls, based upon the Luminex platform. Results from samples tested using these methods were analyzed using 8 different statistical schemes to identify the best way to classify the data. Geographic batteries were also devised to serve as a more practical diagnostic format, and further samples were tested using the abbreviated multiplexes. Comparative error rates for the classification schemes identified a specific boosting method based on logistic regression "Logitboost" as the classification method of choice. When the data from all samples tested were combined into one set, error rates from the multiplex IgM and IgG MIAs were <5% for all geographic batteries. This work represents both the most comprehensive, validated multiplexing method for arboviruses to date, and also the most systematic attempt to determine the most useful classification method for use with these types of serologic tests.

Discover hidden collaborations