We are experienced in establishing high quality bioassay solutions that provide controlled and consistent measurements of biological activity in accordance with relevant industry standards - ICH Q14 (Analytical Procedure Development) and USP1032 (Design and Development of Biological Assays). Selection and development of the method used to measure biological activity, or potency, is amongst the most challenging and complex decisions in CQA definition. Not only is the potency assay likely to correlate most highly with clinical efficacy, frequently there are multiple assay formats and technology platforms that could be used and the methods themselves tend towards to the most complex, exhibiting high variability that requires intimate knowledge of bioassay design to control. Irrespective of where we meet on your drug development journey, Antibody Analytics can guide you on the selection and development of the best methodology.

Together with our regulatory partners, Scendea, we have produced a whitepaper outlining the “Approaches and Regulatory Considerations for the Development of Potency Tests of Early Stage Biological Products” in detail.

Potency assay selection 

The assay must deliver a quantitative measure of the biological activity (termed potency) of a biologic, cell therapy or gene therapy product. Biological activity is defined by the ICHQ6B guideline (Specifications: Test Procedures and Acceptance Criteria for Biotechnological/Biological Products) as the specific ability or capacity of a product to achieve a defined biological effect.  

The selection of an appropriate potency assay is a complex process weighing many considerations including high level information such as the existence of platform methods and the availability of technologies at a CMO. This extends to assay specific considerations such as the ease of performance, ensuring consistency over time, how to navigate multiple mechanisms of action (MMOAs) or simultaneous induction of different pathways. What constitutes a phase-appropriate approach should be considered as well as the benefits of creating a cell-based potency method to support phase I clinical trials directly as the release method or applying it for information only, as an orthogonal method or not at all? Learn more in our whitepaper where we discuss regulatory requirements for selection and implementation. Access Whitepaper.

Our teams have decades of experience designing, developing and conducting potency assays. We can support you to define a phase-appropriate potency assay methodology suited to your modality and MoA. We have created a range of tools that we use to streamline the selection of cell-based methods and have the capabilities to validate the performance of reporter cell line systems against primary models, which although are most functionally relevant, are generally unsuitable for lot release activities. We can  build bespoke reporter systems uniquely suited to your product. 

Our potency assay development tools include: 

• A portfolio of in-house developed signalling reporter cell lines and accompanying assays 
• 384 well plate-based assay formats, employing “thaw and go” cell formats 
• A range of luciferase and target-expressing cell lines, stocked or rapidly-produced in house
• Rapidly customisable cell line platforms – we can insert your gene target(s) of interest into a qualified cell line to produce a target cell line with known susceptibility to the effector mechanism under test 

Advantages of early adoption of a cell-based potency bioassay

We most commonly associate potency assays with lot release and stability assessments but establishing a cell-based potency bioassay prior to formal adoption can provide information across the manufacturing life cycle that cannot be gained by other means. 

Prior to clinical production, data generated from the potency assay can support process development and optimisation decisions relating to product formulation and purification strategies, the effectiveness of scaling up processes as well as product stability. Once a process has been defined or where amendments are required, potency determination can be used to highlight changes in activity associated individual process refinements. At this earlier stage, the bioassay can also play an important role in qualifying the reference standard for use across all analytical testing regimens. 

Enhanced approach to development of a potency assay 

The goal of modern potency assay development is to apply an enhanced approach that is based upon a thorough understanding of bioassay design, together with pre-existing product and assay knowledge gained from the early phases of drug development. Regulatory guidance has evolved significantly to the point where the requirements for the development and overall lifecycle of a potency assay are clearly defined by ICH and FDA guidance; ICH - Q14 (Analytical Procedure Development) and USP 1032 (Design and Development of Biological Assays). Together, these detail an extensive range of activities that need to be considered. 

An Analytical Target Profile (ATP) for the potency assay should be created that defines the intention of the method, together with the anticipated method parameters, with scientific and risk-based strategies for the identification and control of those parameters most likely to impact assay performance. From this, established conditions of the method can be formally defined with the implementation of control strategies to ensure long term method consistency, through adherence to relevant performance criteria. The resulting analytical procedure is a comprehensive document that details the requirements to perform and maintain the potency assay, control critical materials and ensure appropriate operator training. This procedure will evolve over time, in a controlled manner, as additional information regarding the product and process becomes available. 

Key considerations

The inherent variability of bioassays typically prevents the use of absolute measures of potency and instead, a relative potency approach is routinely adopted to manage day-to-day variability. Adopting the relative potency approach is insufficient to completely alleviate variability issues associated with cell-based methodologies and therefore all sources of variability relevant to any given method should be identified and control strategies implemented to minimise their effects. 

Our team advises on a myriad of control strategies which can be applied across a wide and varied set of assay formats. Early implementation of these strategies provides significant benefits in terms of assay performance. Of the multitude of assay factors to consider, those of the overarching assay design, in terms of plate maps and levels of replication, control of materials and system suitability are the most critical.