Cell-based assays are biologically more relevant in predicting therapeutic responses than non-cell-based assays. Hence, cell-based assays can enhance and accelerate drug development timelines more efficiently. Cell-based assays have applications in several processes such as lead candidate selection, drug efficacy, toxicity, and safety evaluations, understanding of target impact on cellular environment, and offering data about drug mechanisms of action.
Cell-based assays can identify patients responding to therapy, monitor biomarkers, and assess immunogenicity testing. Besides, they can evaluate target saturation or engagement, monitor the resistance mechanism, and determine safety markers. Furthermore, cell-based assays can be used for several biochemical and functional effects and are available in different formats, such as cell viability assay, cell proliferation assay, cell-based screening assay, and cell-based functional assay.
As therapeutics evolve in application and complexity, the need for sophisticated bioanalytical methods becomes more important. This need is similar for different bioanalytical assays, such as cell-based and qPCR assays. Advancements in bioanalytical techniques, such as cell-based assays, need robust approaches to validation and standardization. The current article explains cell-based assay validation and standardization.
Cell-based assay validation and standardization
Cell-based assay development and validation are critical for generating reliable data and reaching developmental milestones. Additionally, a better understanding of relevant instrumentation and current regulatory expectations is crucial for developing reliable and efficient cell-based assays.
Regulatory agencies desire drug developers to use cell counting for yield as an in-process control. Besides, they also wish to calculate passage numbers for population doubling levels. Researchers often use this approach to verify the number of cells in each batch while ensuring that sufficient cell numbers are available for further production. Importantly, the acceptance range for population doubling levels should show that no difference across batches will compromise the characteristics or functionality of the cells in production.
Besides, regulators also expect genetic stability testing for cell banks. They need precise methods, for example, fluorescence in situ hybridization or comparative genomic hybridization, to supplement standard karyotyping.
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Assay developers should validate all methods used for in-process control stability and release testing.
Generally, antibiotics are not recommended in cell therapy processing as they can mask the effects of contamination or compromise the performance of sterility tests. Besides, antibiotic traces observed in the final product will be classified as impurities, and regulators may request to test each product of that specific batch.
Potency assays should be included in stability testing as they indicate the biological activity of the API. Assay developers should measure each batch for potential against a reference standard, while the specification should depend on historical data.
Cell-based assay development and validation should be an ever-evolving life cycle. Analytical procedures should be developed early during the preclinical stages and optimized throughout phases 1 and 2 of clinical testing. Once a technique passes this process, assay developers can qualify and validate the method for phase 3 clinical trials. During all phases of drug development, assay developers should conduct routine testing with controls to monitor any changes in the analytical strategies or manufacturing processes.
