A challenging aspect of potency assays is choosing the ideal concentrations for the concentration-response curve analysis. Common optimal design methods are not suited for this type of analysis, as they fail to account for the constraint in a laboratory, as well as the variability between runs that affect the estimation of the relative potency and the similarity test. This talk proposes a simple way to find an efficient concentration range.

As both the technical and regulatory tools for the development and control of biotherapeutic monoclonal antibody products evolve for new modalities and biosimilars, this fast-developing market encounters new challenges. Manufacturers’ reference standards and reference medicinal products are insufficient to ensure product consistency between manufacturers, jurisdictions, and over time. The impact of using international standards on the harmonisation of complex antibody bioassay data from different laboratories will be discussed in light of recent international collaborative studies.

Recently regulatory agencies have lowered sensitivity requirements for anti-drug antibody (ADA) bioassays. Reaching lower sensitivity levels while maintaining drug tolerance may necessitate lengthy acid dissociation pre-treatment steps, affecting assay quality. We present miniaturized, microfluidic ADA immunoassays with an automated acid dissociation step that demonstrate high sensitivity, high-quality, and drug-tolerant assays.

Many opportunities exist to ensure that bioassay measurement is fit for use. This includes but is not limited to strategic development, controls, suitability testing, and standard qualification. All of these must be linked to the bioassay ATP to deliver on their goal. This talk will describe the introduction and maintenance of these throughout the bioassay lifecycle, and how they differ across bioassay uses.

Bioassays are challenging to optimize because they are complex processes with inputs applied to different-sized units. For example, cell-based assays have factors assigned to wells, rows, columns, plates, incubators, and cell preparations. Combining practical constraints from the laboratory with constraints from design of experiments is much easier if we construct the assay with layered or modular design components. Experimental designs for development, validation, and production share common modules, but in different numbers at various levels of the design. By measuring the performance of the method, the properties of reported values for each of several different intended uses can be supported from a single efficient validation (or pre-validation) experiment. Additionally, modular design and appropriate analyses support efficient development and robustness of experiments, as well as allowing easy adjustments to the assay format as the assay system matures. 

Proper evaluation of candidate drugs for desirable pharmacokinetic (PK) properties is imperative to successful biotherapeutic development. We have developed an in vitro cell-based assay to measure transcytosis of monoclonal antibodies (mAbs), which showed a notable correlation between the transcytosis readouts of more than 50 mAbs and their clearance in humans. This assay may serve as a screening tool for predictive assessment of non-specific clearance of antibody-based drug candidates in humans.

Two functional bioassays which better reflect mechanism of action (MoA) of antibody drug by measuring antibody binding-induced target protein enzymatic activity changes are developed to replace and/or supplement an early-phase binding ELISA potency assay. The enzymatical potency assays showed equivalent performance in comparison with binding assay regarding linearity/range, accuracy and precision. The stability-indicating capacity of the enzymatical functional bioassays has also been demonstrated using stability and force-degraded samples.

With higher expectations for potency assay performance, these analytical methods are refined earlier in drug development and have improved capability of detecting process-related differences. Clinical study design changes and evolving technologies for cell and gene therapies have introduced further instances where process, material, or method bridging are required later in development. Case studies will be reviewed with strategies to determine the most appropriate path to bridge these changes.

Cell and gene therapies have the potential to cure previously untreatable diseases, and fundamentally alter the trajectory of many other diseases. Cell and gene therapies have the potential to cure a broad spectrum of diseases and modify the progress of many other diseases. However, the development of new therapeutics comes with a series of challenges and risks. In contrast to traditional therapeutics, large-batch manufacturing and quality testing, these individual batches of cell products, require specific potency assays showing the biological activity. Due to the complexity of most of these cell therapy products, the selection and development of a suitable in vitro potency bioassay comes with certain challenges. Identifying the specific function and mode of action of such a complex product is the first step. Additionally, representing the mode of action in an in vitro assay, using a combination of different cell types, requires optimization and fine tuning on different levels. As an example, the development and optimization of a bioassay to screen for the immunosuppressive function of Mesenchymal Stem Cells will be shown. Next to the evaluation of the potency, in vitro bioassays can be used for the screening of the unwanted immunogenicity of stem cell products. Especially with the increased use of allogenic ‘off the shelf’ therapies, using in vitro bioassays to assess the immunogenicity of stem cell products prior to administration in humans can have significant value.