Assays

Introduction: Technologies Converge in Biopharmaceutical Laboratories

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Bioassay development is foundational to the well-characterized biotechnology product paradigm. Bioassays are the best tools for drug developers to use in determining the biological activity (potency) of their products, which has been a biopharmaceutical critical quality attribute (CQA) since long before that concept had a name. Thus, these assays are vital to quality assurance and quality control (QA/QC), preclinical studies, and clinical testing — and by extension to process development and monitoring. Because of their complex nature, bioassays are among…

March 9, 2021

Direct Analysis of Bioreactor Harvest for Clone Selection and Process Optimization

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Therapeutic monoclonal antibodies (MAbs) mostly are manufactured using bioengineered mammalian cells cultured in a bioreactor for two to three weeks. High temperatures and an altered redox environment may compromise the quality of MAbs produced (e.g., fragmentation, truncation), as can the presence of proteases, reductases, and other chemicals released from dead cells. Thus, it would be valuable to establish analytical methods that can help cell culture groups monitor immunoglobulin G (IgG) product integrity in real time during a bioreactor run, especially…

September 23, 2020

Analytical Testing Strategies for CAR T-Cell Products

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Assay lifecycle development for traditional biopharmaceuticals such as vaccines and monoclonal antibodies (MAbs) has a clearly defined pathway, from preclinical method selection, development, and optimization through the milestones in preclinical phase trials, and finally to postlicensure method evaluations, comparability, and improvements. The analytical development roadmap for nontraditional biologics such as chimeric antigen receptor (CAR) T-cell therapies and gene therapies are not as clearly defined and can present many challenges along the way. Understanding the “what, how, and when†of analytical…

December 16, 2019

eBook: Bioassays for Biopharmaceuticals: Finding Best Practices in a Quality Systems World

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Bioassays are complex and challenging experiments to run reliably with accurate and dependable results. Consistent performance requires a controlled environment and qualified reagents; skilled analysts who understand cell physiology, regulatory requirements, and the latest techniques; and assay protocols that are intelligently developed, characterized, and validated. Here, BPI’s senior technical editor discusses bioassay best practices with representatives of the Biopharmaceutical Emerging Best Practices Association (BEBPA) organization. Topics span quality by design, assay validation, cell banking, potency testing and host-cell protein monitoring,…

October 30, 2019

Creating Novel Cell Lines By Genome Editing: Simplifying Cell-Based Assays and Improving Production of Biomolecules

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Cultured cell lines have a diverse range of applications. They are used broadly by cell biologists, clinicians, tissue engineers, biotechnology scientists, and bioengineers. The most important uses of cell culture are in the cell-based assays and production of biologically active recombinant proteins. In recent years, genome editing has been used widely to study the structure, function, and localization of endogenous proteins in cultured cells. However, applying the same genome editing techniques to cell lines also could improve the propagation of…

September 26, 2019

Biopharmaceutical Characterization,
Part 1: Biological Assays —
A Conference Report

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In late October 2018, KNect365 brought together more than 250 analytical specialists to discuss characterization of well-characterized biologics in Rockville, MD. Speakers from the US Food and Drug Administration joined experts from leading biopharmaceutical companies, service providers, and consultancies, including BPI editorial advisor Nadine Ritter (president and analytical advisor of Global Biotech Experts). She began the final day moderating a special town-hall session where audience members could pose their regulatory questions to a panel of FDA reviewers, and she ended…

December 18, 2018

A Novel 3D Culture System for High-Throughput Hepatoxicity Screening

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Cells grown as three-dimensional (3D) spheroids are thought to more closely mimic in vivo physiology in terms of morphology, structural complexity, and phenotype. Being more physiologically relevant, 3D cultures can be highly predictive for compound profiling and evaluating cytotoxicity, a critical step in evaluating chemotherapeutic drug candidates. Unfortunately, evaluation of drug cytotoxicity traditionally has relied on the use of two-dimensional (2D) cell culture monolayers. When grown in monolayers, cells are not exposed to soluble gradients, are forced into an apical-basal…

October 20, 2018

Certain Approaches to Understanding Sources of Bioassay Variability

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During lifecycle development of a biological assay (bioassay), identifying and reducing sources of variability might be required to improve method performance. Here I recommend some statistical and graphical approaches (consistent with USP <1033>) for practitioners to identify variation from experimental results (1). Sources of Variation in a Bioassay To correctly identify sources of variation in a bioassay, analysts must consider how that bioassay is to be executed. In particular, the experience and technical expertise of each analyst expected to execute…

October 20, 2018

Statistical Assessments of Bioassay Validation Acceptance Criteria

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Analytical linearity as well as assessments of precision and accuracy determine the range for a bioassay (1). USP <1033> recommends comparing confidence intervals (CIs) against target validation acceptance criteria in a bioassay validation exercise, but there are no clear guidelines for determining the criteria (2). Here I address several aspects of a bioassay validation, namely • Linearity (coefficient of determination (R2), slope, and intercept parameters) • Accuracy (%relative bias, %RB) • Precision (percent coefficient of variation, %CV) CIs for the…

June 1, 2018

The Relationship Between R2 and Precision in Bioassay Validation

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Analytical linearity along with assessments of precision and accuracy determine the range for bioassays (1). Practitioners can include coefficient of determination (R2) criteria from a linearity study in the bioassay validation protocol. Herein I illustrate the relationship of R2 to study design and analytical method variation. Overview of the Simple Linear Regression Model Dilutional linearity assesses the “ability (within a given range) of a bioassay to obtain measured relative potencies that are directly proportional to the true relative potency of the…

April 20, 2018